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Final Program and Abstracts

Society for Industrial and Applied Mathematics3600 Market Street, 6th Floor

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www.siam.org/meetings/nc17

2 SIAM Conference on Numerical Combustion

Table of Contents

Program-At-A-Glance…Fold out section

General Information .............................2

Get-together .........................................4

Invited Plenary Presentations ...............5

Program Schedule ................................7

Abstracts ............................................31

Speaker and Organizer Index .............93

Conference Budget…Inside Back Cover

Hotel Meeting Room Map…Back Cover

Organizing Committee Co-chairs

Mitchell D. SmookeYale University, USA

D. Scott StewartUniversity of Illinois, Urbana-

Champaign, USA

Charles WestbrookLawrence Livermore National

Laboratory, USA

Steering CommitteeStewart CantUniversity of Cambridge, United

Kingdom

Jackie Chen Sandia National Laboratories, USA

Vincent GiovangigliEcole Polytechnique, France

Ulrich MaasKarlsruhe Institute of Technology,

Germany

Elaine OranUniversity of Maryland, USA

Denis Veynante Ecole Centrale Paris, France

Hotel AddressRosen Plaza Hotel 9700 International Drive Orlando, Florida 32819 USA Phone Number: +1 (407) 996-9700 Toll Free Reservations (USA and Canada): (800) 627-8258 Reservation Fax: +1 (407) 996-3157 Hotel website: http://www.rosenplaza.com/

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Hotel Check-in and Check-out TimesCheck-in time is 3:00 PM.

Check-out time is 11:00 AM.

SIAM Registration Desk The SIAM registration desk is located at Registration Desk C on the Lobby Level. It is open during the following hours:

Sunday, April 2

5:00 PM - 8:00 PM

Monday, April 3

7:00 AM - 4:00 PM

Tuesday, April 4

7:30 AM - 4:00 PM

Wednesday, April 5

7:30 AM - 1:30 PM

Child CareThe Orlando Convention and Visitors Bureau recommends Super Sitters (http://www.orlandomeeting.com/meeting-services-support/on-site-services/super-sitters/44627/) for attendees interested in child care services. Attendees are respon-sible for making their own child care arrangements.The Rosen Plaza Hotel offers babysitting services for additional fees. Please call Kid’z Night Out at 407-828-0920 or the hotel concierge at 407-996-9700 for more details.

Corporate Members and AffiliatesSIAM corporate members provide their employees with knowledge about, access to, and contacts in the applied mathematics and computational sciences community through their membership benefits. Corporate membership is more than just a bundle of tangible products and services; it is an expression of support for SIAM and its programs. SIAM is pleased to acknowledge its corporate members and sponsors. In recognition of their support, non-member attendees who are employed by the following organizations are entitled to the SIAM member registration rate.

Corporate Institutional MembersThe Aerospace Corporation

Air Force Office of Scientific Research

Amazon

Aramco Services Company

Bechtel Marine Propulsion Laboratory

The Boeing Company

CEA/DAM

Department of National Defence (DND/CSEC)

DSTO- Defence Science and Technology Organisation

Hewlett-Packard

Huawei FRC French R&D Center

IBM Corporation

IDA Center for Communications Research, La Jolla

IDA Center for Communications Research, Princeton

Institute for Defense Analyses, Center for Computing Sciences

Lawrence Berkeley National Laboratory

Lawrence Livermore National Labs

Lockheed Martin

Los Alamos National Laboratory

SIAM Conference on Numerical Combustion 3

Max-Planck-Institute for Dynamics of Complex Technical Systems

Mentor Graphics

National Institute of Standards and Technology (NIST)

National Security Agency (DIRNSA)

Naval PostGrad

Oak Ridge National Laboratory, managed by UT-Battelle for the Department of Energy

Sandia National Laboratories

Schlumberger-Doll Research

United States Department of Energy

U.S. Army Corps of Engineers, Engineer Research and Development Center

US Naval Research Labs

List current February 2017.

Funding AgencySIAM and the Conference Organizing Committee wish to extend their thanks and appreciation to the DOE Office of Advanced Scientific Computing Research for its support of this conference.

Leading the applied mathematics community

Join SIAM and save!SIAM members save up to $130 on full registration for the Sixteenth International Conference on Numerical Combustion (NC17)! Join your peers in supporting the premier professional society for applied mathematicians and computational scientists. SIAM members receive subscriptions to SIAM Review, SIAM News and SIAM Unwrapped, and enjoy substantial discounts on SIAM books, journal subscriptions, and conference registrations.

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Join onsite at the registration desk, go to www.siam.org/joinsiam to join online or download an application form, or contact SIAM Customer Service:

Telephone: +1-215-382-9800 (worldwide); or 800-447-7426 (U.S. and Canada only)

Fax: +1-215-386-7999

E-mail: [email protected]

Postal mail: Society for Industrial and Applied Mathematics, 3600 Market Street, 6th floor, Philadelphia, PA 19104-2688 USA

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• Coffee breaks daily

• Continental Breakfast Daily

• Room set-ups and audio/visual equipment

• Welcome Reception

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Get-together• Welcome Reception

Sunday, April 2

6:00 PM – 8:00 PM

Statement on InclusivenessAs a professional society, SIAM is committed to providing an inclusive climate that encourages the open expression and exchange of ideas, that is free from all forms of discrimination, harassment, and retaliation, and that is welcoming and comfortable to all members and to those who participate in its activities. In pursuit of that commitment, SIAM is dedicated to the philosophy of equality of opportunity and

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Invited Plenary Speakers** All Invited Plenary Presentations will take place in Ballroom C on the Lobby Level**

Monday, April 3

8:15 AM - 9:00 AM IP1 Modeling Flame Holes in Turbulent Nonpremixed Flows

Carlos Pantano, University of Illinois at Urbana-Champaign, USA

Tuesday, April 4

8:15 AM - 9:00 AM IP2 Progress and Challenges in Simulating Combustion Systems with Realistic Chemistry

Perrine Pepiot, Cornell University, USA

Wednesday, April 5

8:15 AM - 9:00 AM IP3 Dynamic Partitioning and Quantum Speedup for Turbulent Combustion Simulation

Peyman Givi, University of Pittsburgh, USA


NC17 Program


Sunday, April 2

Registration5:00 PM-8:00 PMRoom:Registration Desk C - Lobby Level

Welcome Reception6:00 PM-8:00 PMRoom:Upper Pool Deck

Monday, April 3

Registration7:00 AM-4:00 PMRoom:Registration Desk C - Lobby Level

Continental Breakfast7:30 AMRoom:Ballroom C Foyer - Lobby Level

Welcoming Remarks8:00 AM-8:15 AMRoom:Ballroom C - Lobby Level

Monday, April 3

IP1Modeling Flame Holes in Turbulent Nonpremixed Flows8:15 AM-9:00 AMRoom:Ballroom C - Lobby Level

Chair: Moshe Matalon, University of Illinois at Urbana-Champaign, USA

Turbulent diffusion flames can be quenched in regions of high strain owing to increased heat loss away from the reaction zone. These chemically inert regions are sometimes called flame holes (Dold et al. 1991). Turbulent flames with extinction are relevant in modern combustors where the flame temperature is kept low to reduce pollutant formation or in lifted jet flames used for thermal protection of the burner. Modeling the dynamical behavior of flame holes, without recourse to a detailed chemical-transport description, requires new numerical methods that describe the evolution in time of the flame boundary (or rim) on the moving stoichiometric surface. The kinematics of the flame rim is normally approximated as those of a two-dimensional edge flame whose speed of propagation is controlled by the local strain. In mathematical terms, the challenge is the efficient numerical evolution of a state field defined on a two-manifold (of varying shape, and possibly multiply connected). In this talk, I will describe recent progress on the numerical and physical modeling of flame holes as it applies to turbulent nonpremixed flames. Special emphasis of current research is to achieve high-order of accuracy, flexibility, and robustness, while maintaining relatively low computational cost.

Carlos PantanoUniversity of Illinois at Urbana-Champaign, USA

Coffee Break9:00 AM-9:30 AMRoom:Ballroom C Foyer - Lobby Level


Monday, April 3

CP1Energetic Materials9:30 AM-11:30 AMRoom:Ballroom C - Lobby Level

Chair: Thomas Jackson, University of Florida, USA

9:30-9:45 High Explosive Performance Modeling Using the Pseudo-Reaction Zone Energy Release Model in Programmed BurnCarlos Chiquete, Mark Short, Chad

Meyer, and James Quirk, Los Alamos National Laboratory, USA

9:50-10:05 Mesoscale Simulations of Energetic Materials Using Density-Based KineticsThomas Jackson, University of Florida,

USA; Ju Zhang, Florida Institute of Technology, USA

10:10-10:25 Numerical Simulation of Detonation Propagation in Practical GeometriesDamien Masselot, Takuma Sato, and

Venkat Raman, University of Michigan, USA

10:30-10:45 A DSD Model for Converging DetonationsJin Yao, Laurence E. Fried, and Peter A.

Vitello, Lawrence Livermore National Laboratory, USA

10:50-11:05 Condensed-Phase Oblique Detonation Interaction with a Rigid WallMark Short, Los Alamos National

Laboratory, USA; John Bdzil, University of Illinois at Urbana-Champaign, USA; Carlos Chiquete and Chad Meyer, Los Alamos National Laboratory, USA

11:10-11:25 Modeling of Aluminum Combustion in An Oxidizing Environment with the Gibbs FormulationD. Scott Stewart, University of Illinois at

Urbana-Champaign, USA

Monday, April 3

CP2Electric Fields9:30 AM-11:10 AMRoom:Salon 5 - Mezzanine Level

Chair: Ali Charchi Aghdam, University of South Carolina, USA

9:30-9:45 A Computational Study of Ionic Wind Effects on Dynamics of Nonpremixed Counterflow Flames Subjected to DC Electric FieldsMemdouh Belhi, Bok Jik Lee, and

Hong G. Im, King Abdullah University of Science & Technology (KAUST), Saudi Arabia

9:50-10:05 Simulation of Plasma Initiation in Liquid MediumAli Charchi Aghdam and Tanvir

Farouk, University of South Carolina, USA

10:10-10:25 A Spectral Deferred Correction Strategy for Low Mach Number Reacting Flows Subject to Electric FieldsValentina Ricchiuti and Marc Day,

Lawrence Berkeley National Laboratory, USA

10:30-10:45 Simulating Interactions of Detonation, Ionization Chemistry, and MagnetohydrodynamicsMatthew F. Zaiger, David Blunck,

and Kyle E. Niemeyer, Oregon State University, USA

10:50-11:05 DNS of Partially Premixed Mild CombustionNguyen Anh Khoa Doan and

Nedunchezhian Swaminathan, University of Cambridge, United Kingdom; Yuki Minamoto, Tokyo Institute of Technology, Japan

Monday, April 3

CP3Flamelets and Tabular9:30 AM-11:30 AMRoom:Salon 6 - Mezzanine Level

Chair: Michael A. Hansen, University of Utah, USA and Sandia National Laboratories, USA

9:30-9:45 Spectral Matrix Analysis of the Semi-Discrete Flamelet EquationsMichael A. Hansen, University of

Utah, USA and Sandia National Laboratories, USA; James C. Sutherland, University of Utah, USA

9:50-10:05 An RCCE-ANN Tabulation Approach Applied to Sydney Flame LLucas Franke and Stelios Rigopoulos,

Imperial College London, United Kingdom

10:10-10:25 Comparison of Differential Diffusion Flamelet Modeling Approaches in Turbulent Oxy-Fuel FlamesSandro Gierth, Franziska Hunger,

and Sebastian Popp, Technische Universität Bergakademie Freiberg, Germany; Matthias Ihme, Stanford University, USA; Christian Hasse, Technische Universität Bergakademie Freiberg, Germany

10:30-10:45 The Laminar Flamelet Model Combined with Collision Porosity Distance Algorithm Applied to Accidental Explosion ModellingTatiele Ferreira, Rogério Santos,

and Sávio Vianna, University of Campinas, Brazil

10:50-11:05 Portable Tabulation for Thermochemical and Radiation Properties in Combustion SimulationsBabak Goshayeshi and James C.

Sutherland, University of Utah, USA

11:10-11:25 Assessment of Flamelet Tabulation Strategies for Pulverized Coal Combustion in a Strained Flow ConfigurationArne Scholtissek, Danny Messig,

Michele Vascellari, and Christian Hasse, Technische Universität Bergakademie Freiberg, Germany


Monday, April 3

MS1Numerical Modelling and Simulation of Detonations in High-Energy Explosives - Part I of II1:00 PM-3:00 PMRoom:Ballroom C - Lobby Level

For Part 2 see MS3 Predictive numerical modelling of initiation and detonation propagation in high-energy (HE) explosives is vital for their safe handling and use. This two-part minisymposium focuses on current challenges in modelling and computation of HE explosives. Eight presentations will address subjects on the development of appropriate equation of state and reaction rates for condensed-phase explosive modelling, cook-off, cylinder test modelling, multi-dimensional shock fitting techniques, whole-system condensed-phase explosive detonation interaction with highly-deformable elastoplastic materials, multi-scale modelling of compaction-initiated detonation and the role of spatial heterogeneities on the propagation limit of detonations.

Organizer: Louisa MichaelUniversity of Cambridge, United Kingdom

1:00-1:25 Whole-System Detonation Modelling for Practical ApplicationsEleftherios Ioannou, Louisa Michael, and

Nikolaos Nikiforakis, University of Cambridge, United Kingdom

1:30-1:55 Equations of State for Predictive Modelling of Confined, Condensed-Phase ExplosivesSimon D. Wilkinson, Nikolaos

Nikiforakis, and Louisa Michael, University of Cambridge, United Kingdom

Monday, April 3

CP4Kinetics and Sprays I9:30 AM-11:30 AMRoom:Salon 7 - Mezzanine Level

Chair: Giulio Borghesi, Sandia National Laboratories, USA

9:30-9:45 DNS of An Autoigniting Air / N-Dodecane Temporal Jet at Diesel Engine ConditionsGiulio Borghesi and Jacqueline Chen,

Sandia National Laboratories, USA

9:50-10:05 Modeling N-Dodecane Spray Combustion with a Representative Interactive Linear Eddy ModelTim Lackmann, Chalmers University

of Technology, Sweden; Tommaso Lucchini and Gianluca D’Errico, Politecnico di Milano, Italy; Alan Kerstein, Consultant, USA; Michael Oevermann, Chalmers University of Technology, Sweden

10:10-10:25 Analysis and Regimes of Multicomponent Spray Combustion Using DNSPavan B. Govindaraju and Matthias

Ihme, Stanford University, USA

10:30-10:45 Coupled Eulerian-Lagrangian LES-pdf Simulation of a Combustion System with Full Resolution of the Primary AtomisationFabien Evrard, Simon Gallot-Lavallée,

Fabian Denner, Berend van Wachem, and William Jones, Imperial College London, United Kingdom

10:50-11:05 Eulerian Simulation of Polydisperse Two-Phase Flame Propagation in a Turbulent Flow for a Large Range of Stokes NumbersDennis Dunn, Macole Sabat, and

Jean Michel Dupays, CNRS, CentraleSupélec, France; Jorge César Brandle De Motta, CORIA, France; Aymeric Vié, CNRS, France; Frédérique Laurent and Marc Massot, CNRS, CentraleSupélec, France

11:10-11:25 Numerical Investigation of the Stability of a Spray Oxyfuel Flame Diluted by Carbon DioxideSimon Gallot-Lavallée, Dongwon Noh,

Andrew Marquis, and William Jones, Imperial College London, United Kingdom

Monday, April 3

CP5Stability9:30 AM-11:30 AMRoom:Salon 8 - Mezzanine Level

Chair: Meysam Sahafzadeh, Ryerson University, Canada

9:30-9:45 Linear Stability Analysis of Detonation Waves with Realistic Chemical Kinetic SchemesCharles B. Kiyanda, Concordia

University, Canada; Mark Short, Los Alamos National Laboratory, USA

9:50-10:05 The Role of Darrieus-Landau Instability on Turbulent Premixed Flame PropagationPasquale Lapenna, Rachele Lamioni, and

Francesco Creta, Universita di Roma “La Sapienza,” Italy; Guido Troiani, ENEA Centro Ricerche Casaccia, Italy

10:10-10:25 Accuracy and Stability of Finite Differences in Premixed Combustion DNSRobert Prosser, University of

Manchester, United Kingdom

10:30-10:45 Nonlinear Frequency Response Analysis of Laminar Premixed FlamesMeysam Sahafzadeh, Ryerson University,

Canada; Larry Kostiuk, University of Alberta, Canada; Seth Dworkin, Ryerson University, Canada

10:50-11:05 Thermoacoustics of Annular CombustorsAudrey Valreau, Chin Yik Lee, and

Stewart Cant, University of Cambridge, United Kingdom

11:10-11:25 Flame Stabilisation and Dynamics in a Sequential Combustor at Atmospheric and High PressureOliver Schulz and Nicolas Noiray, ETH

Zürich, Switzerland

Lunch Break11:30 AM-1:00 PMAttendees on their own

continued on next page


2:00-2:25 A Multi-Scale Model of Compaction-Driven Initiation of DetonationJames R. Gambino, Lawrence

Livermore National Laboratory, USA; Donald W. Schwendeman and Ashwani K. Kapila, Rensselaer Polytechnic Institute, USA

2:30-2:55 Propagation Limit of Detonation Waves in a Spatially Heterogeneous Reactive Medium with Yielding ConfinementXiaoCheng Mi and Andrew Higgins,

McGill University, Canada; Hoi Dick Ng and Charles B. Kiyanda, Concordia University, Canada; Nikolaos Nikiforakis, University of Cambridge, United Kingdom

Monday, April 3

MS2Uncertainty Quantification and Model Inadequacy in Combustion Simulations - Part I of II1:00 PM-3:00 PMRoom:Salon 5 - Mezzanine Level

For Part 2 see MS4 Uncertainty and model inadequacy are ubiquitous in combustion modeling. In high-fidelity simulations that fully resolve all relevant physical scales and use detailed kinetics mechanisms, there are often hundreds of uncertain Arrhenius rate parameters. Lower fidelity models also involve uncertain parameters (e.g., imperfectly known kinetics and turbulence model parameters). Possibly more important, these lower-fidelity models generally introduce significant modeling errors through the use of reduced kinetics, simplified representations of turbulence and turbulence/chemistry interactions, or both. Quantification of all of these sources of uncertainty involves a host of modeling and algorithmic challenges, including, but not limited to, 1) development of defensible approaches for representing model inadequacy for reduced kinetics models and for RANS and LES turbulence closures and 2) development of tractable algorithms (e.g., by using surrogate models) for treating high-dimensional uncertainties in computationally expensive simulations. This minisymposium brings together researchers from a range of backgrounds working to develop state-of-the-art methods for meeting these UQ challenges in the context of combustion problems.

Organizer: Boris KramerMassachusetts Institute of Technology, USA

Organizer: Todd A. OliverUniversity of Texas at Austin, USA

1:00-1:25 Calibration of a Stochastic Operator-Based Model Inadequacy Representation for Chemical KineticsDavid Sondak, Todd A. Oliver, and

Robert D. Moser, University of Texas at Austin, USA

1:30-1:55 Towards Model Inadequacy Representations for Flamelet-Based Combustion ModelsTodd A. Oliver, David Sondak, Chris

Simmons, and Robert D. Moser, University of Texas at Austin, USA

2:00-2:25 Open-Source Software for Uncertainty Quantification in Reacting FlowsPaul Bauman, State University of New

York at Buffalo, USA

2:30-2:55 Multifidelity Failure Probability Estimation in Combustion ModelingBoris Kramer, Benjamin Peherstorfer,

and Karen E. Willcox, Massachusetts Institute of Technology, USA

continued in next column


Monday, April 3

CP6Dimension Manifolds I1:00 PM-3:00 PMRoom:Salon 6 - Mezzanine Level

Chair: Stewart Cant, University of Cambridge, United Kingdom

1:00-1:15 Transported PDF Modeling of Turbulent Flames Using the Flamelet Generated Manifold Chemistry ModelMichael Stoellinger and Vasu Jaganath,

University of Wyoming, USA

1:20-1:35 Identification of Low-Dimensional Manifolds in Coal CombustionJosh T. Mcconnell and James C.

Sutherland, University of Utah, USA

1:40-1:55 Numerical Simulation of Transcritical H2/O2 FlameUmut Guven, CORIA, France;

Guillaume Ribert, INSA de Rouen, France

2:00-2:15 Numerical Methods for Transcritical Real-Fluid Reacting Flows Using the Flamelet Progress Variable ApproachPeter C. Ma, Yu Lv, and Daniel Banuti,

Stanford University, USA; Jean-Pierre Hickey, University of Waterloo, Canada; Matthias Ihme, Stanford University, USA

2:20-2:35 A Web-Based Tool for Simulation and Numerical Analysis of Zero-Dimensional Combustion ProblemsElizabeth Armstrong, Michael Hansen,

and James C. Sutherland, University of Utah, USA

2:40-2:55 The First Investigation of the Hamish Code: An Adaptive Mesh Solver for Turbulent Reacting FlowsJian Fang and Charles Moulinec,

Daresbury Laboratory, United Kingdom; David Emerson, STFC Daresbury Laboratory, United Kingdom; Nilanjan Chakraborty, Newcastle University, United Kingdom; Stewart Cant, University of Cambridge, United Kingdom

2:00-2:15 Large-Eddy Simulation of Light-Round in an Annular Combustor Equipped with N-Heptane Spray InjectorsThea Lancien, CNRS, CentraleSupélec,

France; Kevin Prieur, Safran Tech, France; Daniel Durox, Ecole Centrale Paris, France; Sebastien Candel, CNRS, CentraleSupélec, France; Ronan Vicquelin, Ecole Centrale Paris, France

2:20-2:35 Modeling of Isolated Droplet Combustion of Sooting Fuels Under Microgravity EnvironmentFahd E. Alam, University of South

Carolina, USA; Frederick L. Dryer, Princeton University, USA; Tanvir I. Farouk, University of South Carolina, USA

2:40-2:55 Droplet Formation and Recognition: A Droplet Tracking Algorithm for Primary Breakup ModellingCamille Bilger and Stewart Cant,

University of Cambridge, United Kingdom

Monday, April 3

CP7Kinetics and Sprays II1:00 PM-3:00 PMRoom:Salon 7 - Mezzanine Level

Chair: Fahd E. Alam, University of South Carolina, USA

1:00-1:15 A Filtered Tabulated Chemistry Model for LES of Spray CombustionAdrien Chatelier, Université Paris-Saclay,

France; Nasser Darabiha, CNRS, France; Nicolas Bertier, ONERA, France; Benoit Fiorina, École Centrale de Paris, France

1:20-1:35 Conjugate Heat Transfer Modeling in a Kerosene/Air Spray Flame Impacting a Plate. Application to Fire Resistance on Helicopter CrankcasesLancelot Boulet, CORIA, France; Pierre

Bénard, Université de Rouen, France; Ghislain Lartigue and Vincent R. Moureau, CORIA, France; Sheddia Didorally, Safran Helicopter Engines, France

1:40-1:55 Counter-Flow Spray Pulsated Flames: From Experimental Measurements to Numerical SimulationJorge Cesar Brandle De Motta,

Université de Rouen, France; Dennis Dunn, CNRS, CentraleSupélec, France; Matthieu Boileau, Université de Strasbourg, France; Laurent Zimmer and Benjamin Robbes, CNRS, CentraleSupélec, France; Eleonore Riber and Bénédicte Cuenot, CERFACS, France; Julien Réveillon, Université de Rouen, France; Frédérique Laurent-Nègre and Marc Massot, CNRS, CentraleSupélec, France



Monday, April 3

CP8Soot1:00 PM-3:00 PMRoom:Salon 8 - Mezzanine Level

Chair: Shao Teng Chong, University of Michigan, USA

1:00-1:15 Scaling of Sooting Laminar Coflow Flames at Elevated Pressures: A New AppraochAhmed Abdelgadir and Scott Steinmetz,

King Abdullah University of Science & Technology (KAUST), Saudi Arabia; Antonio Attili, RWTH Aachen University, Germany; Fabrizio Bisetti, University of Texas at Austin, USA; William Roberts, King Abdullah University of Science & Technology (KAUST), Saudi Arabia

1:20-1:35 Comparison of Moments-Based Approaches for Modeling Soot Population in Turbulent FlowsShao Teng Chong and Venkat Raman,

University of Michigan, USA; Paul Arias, University of Michigan, Ann Arbor, USA; Hong Im, King Abdullah University of Science & Technology (KAUST), Saudi Arabia

1:40-1:55 Development of a Soot Particle Concentration Estimation Library for Industrial Combustion ApplicationsRaymond Alexander and Seth Dworkin,

Ryerson University, Canada

2:00-2:15 Numerical Simulation of Soot Formation in Diffusion FlamesNemanja Ceranic and Seth Dworkin,

Ryerson University, Canada

2:20-2:35 A Multi-Variate Sectional Method for the Description of Soot Production in Large Eddy SimulationBenedetta G. Franzelli, Aymeric Vié, and

Nasser Darabiha, CNRS, France

2:40-2:55 Monte Carlo Simulation of Particle Formation in Premixed Flames Using a Detailed Soot ModelSteffen Salenbauch, Technische

Universität Bergakademie Freiberg, Germany; Mariano Sirignano and Andrea D’Anna, Università degli Studi di Napoli Federico II, Italy; Daniele Marchisio and Marco Vanni, Politecnico di Torino, Italy; Christian Hasse, Technische Universität Bergakademie Freiberg, Germany

Monday, April 3Coffee Break3:00 PM-3:30 PMRoom:Ballroom C Foyer - Lobby Level

Monday, April 3

MS3Numerical Modelling and Simulation of Detonations in High-Energy Explosives - Part II of II3:30 PM-5:30 PMRoom:Ballroom C - Lobby Level

For Part 1 see MS1 Predictive numerical modelling of initiation and detonation propagation in high-energy (HE) explosives is vital for their safe handling and use. This two-part minisymposium focuses on current challenges in modelling and computation of HE explosives. Eight presentations will address subjects on the development of appropriate equation of state and reaction rates for condensed-phase explosive modelling, cook-off, cylinder test modelling, multi-dimensional shock fitting techniques, whole-system condensed-phase explosive detonation interaction with highly-deformable elastoplastic materials, multi-scale modelling of compaction-initiated detonation and the role of spatial heterogeneities on the propagation limit of detonations.

Organizer: Louisa MichaelUniversity of Cambridge, United Kingdom

3:30-3:55 A New Approach for Cook-Off ModellingHaran Jackson and Nikolaos Nikiforakis,


4:00-4:25 A Thermochemical Algorithm for Combustion ModellingGeraint Harcombe, Nikolaos Nikiforakis,

and Martin Braithwaite, University of Cambridge, United Kingdom

4:30-4:55 Direct Construction of the Steady Traveling High Explosive Cylinder TestTariq D. Aslam, Los Alamos National

Laboratory, USA

5:00-5:25 Robust Multi-Dimensional Shock-FittingChristopher Romick, Eureka Physics,

USA; Tariq D. Aslam, Los Alamos National Laboratory, USA


Monday, April 3

MS4Uncertainty Quantification and Model Inadequacy in Combustion Simulations - Part II of II3:30 PM-5:00 PMRoom:Salon 5 - Mezzanine Level

For Part 1 see MS2 Uncertainty and model inadequacy are ubiquitous in combustion modeling. In high-fidelity simulations that fully resolve all relevant physical scales and use detailed kinetics mechanisms, there are often hundreds of uncertain Arrhenius rate parameters. Lower fidelity models also involve uncertain parameters (e.g., imperfectly known kinetics and turbulence model parameters). Possibly more important, these lower-fidelity models generally introduce significant modeling errors through the use of reduced kinetics, simplified representations of turbulence and turbulence/chemistry interactions, or both. Quantification of all of these sources of uncertainty involves a host of modeling and algorithmic challenges, including, but not limited to, 1) development of defensible approaches for representing model inadequacy for reduced kinetics models and for RANS and LES turbulence closures and 2) development of tractable algorithms (e.g., by using surrogate models) for treating high-dimensional uncertainties in computationally expensive simulations. This minisymposium brings together researchers from a range of backgrounds working to develop state-of-the-art methods for meeting these UQ challenges in the context of combustion problems.

Organizer: Boris KramerMassachusetts Institute of Technology, USA

Organizer: Todd A. OliverUniversity of Texas at Austin, USA

Monday, April 3

CP9Numerical Methods I3:30 PM-5:30 PMRoom:Salon 6 - Mezzanine Level

Chair: Abdurrahman Imren, Pennsylvania State University, USA

3:30-3:45 Surrogate Models Based on the Combination of PCA and KrigingGianmarco Aversano, Université Libre

de Bruxelles, Belgium

3:50-4:05 Encouraging Modern Software Development Practices for CombustionKyle E. Niemeyer, Oregon State

University, USA; Raymond L. Speth, Massachusetts Institute of Technology, USA; Bryan W. Weber, University of Connecticut, USA; Richard West, Northeastern University, USA

4:10-4:25 Improved Extrapolation-Based Stiff ODE Solvers for Combustion CFDAbdurrahman Imren and Daniel

C. Haworth, Pennsylvania State University, USA

4:30-4:45 The Discontinous-Galerkin Method for Chemical Source Term Integration in the Reacting Navier-Stokes EquationsRyan F. Johnson, Andrew Corrigan,

Douglas Schwer, Andrew Kercher, and Kazhikathra Kailasanath, Naval Research Laboratory, USA

4:50-5:05 Efficient Numerical Algorithms Using Asymptotic Estimation of Mesh Parameter for Singularly Perturbed Boundary Value Problems with and Without Turning PointRamesh Vp, Prithvi M, and Priyanga

B, Central University of Tamil Nadu, India

5:10-5:25 Analysis of Operator Splitting Errors for Near-Limit Flame SimulationsZhen Lu, Hua Zhou, Shan Li, and

Zhuyin Ren, Tsinghua University, China; Tianfeng Lu, University of Connecticut, USA; Chung K. Law, Princeton University, USA

3:30-3:55 Quantifying Uncertainty from Model Error in Turbulent Combustion ApplicationsXun Huan, Khachik Sargsyan, Zachary

Vane, Guilhem Lacaze, Joseph C. Oefelein, and Habib N. Najm, Sandia National Laboratories, USA

4:00-4:25 Physics-Derived Model Form Uncertainty Quantification for Turbulent CombustionMichael E. Mueller, Princeton

University, USA; Venkat Raman, University of Michigan, USA

4:30-4:55 Reduced-Order Modeling of Combustion Reactions in Uncertainty QuantificationAlan Lattimer, Jensen Hughes, USA



Monday, April 3

CP10Heat Transfer and Radiation3:30 PM-5:30 PMRoom:Salon 7 - Mezzanine Level

Chair: Jian Cai, University of Wyoming, USA

3:30-3:45 Modeling Radiative Heat Transfer in Gas-Solid Reacting FlowsJian Cai, University of Wyoming, USA

3:50-4:05 Heat Release Effects on Turbulence Statistics in Premixed and Nonpremixed FlamesJonathan F. Macart, Temistocle Grenga,

and Michael E. Mueller, Princeton University, USA

4:10-4:25 Effect of Heat Transfer on Flame Stabilization and DynamicsAbdulla Ghani, Daniel Mejia, Laurent

Selle, and Thierry Poinsot, IMF Toulouse, France

4:30-4:45 Radiative Heat Transfer Modelling in a Heavy-Duty Diesel EngineChandan Paul, Arpan Sircar, Sebastian

Ferreyro-Fernandez, Abdurrahman Imren, and D. C. Haworth, Pennsylvania State University, USA; S. Roy, Marquette University, USA; W. Ge and M. F. Modest, University of California, Merced, USA

4:50-5:05 Turbulence Radiation Coupling in Boundary Layers of Heavy-Duty Diesel EnginesArpan Sircar, Chandan Paul, Sebastian

Ferreyro-Fernandez, Abdurrahman Imren, and Daniel Haworth, Pennsylvania State University, USA; Somesh P. Roy, Marquette University, USA; Wenjun Ge and Michael Modest, University of California, Merced, USA

5:10-5:25 Premixed Flame Propagation in a Boundary LayerKevin Bioche, CORIA CNRS & INSA

Rouen Normandie, France; Guillaume Ribert, INSA de Rouen, France; Luc Vervisch, INSA Rouen, France

Tuesday, April 4



Remarks8:10 AM-8:15 AMRoom:Ballroom C - Lobby Level

Monday, April 3

CP11LES I3:30 PM-5:10 PMRoom:Salon 8 - Mezzanine Level

Chair: Kevin Grogan, Stanford University, USA

3:30-3:45 Large Eddy Simulation and Probability Density Function Modelling of High-Speed Reacting FlowsYuri Paixao de Almeida and Salvador

Navarro-Martinez, Imperial College London, United Kingdom

3:50-4:05 Large Eddy Simulation of Air-Flow Modulation on the Dynamics of Two-Phase Swirling Flames for Two Different Fuel Injection TechnicsLeo Cunha Caldeira Mesquita, Artur

Carvalho Santos, and Benoit Cheneau, Université Paris-Saclay, France; Aymeric Vié, CNRS, France; Sébastien Ducruix, EM2C Laboratory, France

4:10-4:25 A Large Eddy Simulation of a Rotating Detonation EngineKevin Grogan, Stanford University,

USA; Brent Rankin, Air Force Research Laboratory, USA; John Hoke, Innovative Scientific Solution, USA; Matthias Ihme, Stanford University, USA

4:30-4:45 Large-Eddy Simulation of Pulverised-Coal CombustionPascale Domingo, CORIA, France;

Dorian Midou, CORIA CNRS & INSA Rouen Normandie, France; Luc Vervisch, INSA Rouen, France

4:50-5:05 Large Eddy Simulation of Reacting Flows at High Pressures Using GPU AccelerationRamanan Sankaran and Kalyana

Gottiparthi, Oak Ridge National Laboratory, USA; Joseph C. Oefelein, Sandia National Laboratories, USA


10:30-10:55 Global Sensitivity Analysis with Small Sample Sizes for Large Scale Combustion SimulationsMichael J. Davis, Argonne National

Laboratory, USA

11:00-11:25 Use of Uncertainty Quantification in Tools for Autonomous Scientific InquiryMichael P. Burke, Argonne National

Laboratory, USA

Tuesday, April 4

IP2Progress and Challenges in Simulating Combustion Systems with Realistic Chemistry8:15 AM-9:00 AMRoom:Ballroom C - Lobby Level

Chair: Mitchell Smooke, Yale University, USA

The vital role of simulations and computational insights in reducing pollutant emissions, designing better engines and better fuels, and assessing the technical and economic viability of radically different combustion technologies, is now clearly established. A key enabling step is the development of computational approaches that allow our increasingly detailed knowledge of the chemical kinetics of realistic fuel oxidation to be applied to the modeling and simulation of combustion reactors. In this talk, I will briefly review the challenges associated with the integration of detailed chemical kinetics in reactive flow simulations. I will then discuss the progress we have made in the analysis and reduction of complex kinetic networks, with a focus on graph-based techniques and the characteristics of the stand-alone reduced models they typically generate. Using Large-Eddy Simulations of turbulent flames as case study, I will show how these techniques are enhanced through careful integration and coupling with CFD tools, wherein the flow characteristics adaptively inform the reduced chemical model to be used. I will conclude on the remaining challenges still to overcome, and potential avenues to do so.

Perrine PepiotCornell University, USA


Tuesday, April 4

MS5Uncertainty Quantification in Computational Combustion - Part I of III9:30 AM-11:30 AMRoom:Ballroom C - Lobby Level

For Part 2 see MS7 Predictive combustion computations rely on calibrated and validated models. These models rely on parameters that are estimated either from experimental measurements or from theory/computations, and are, to some extent, uncertain. Accordingly, it is important that computational predictions based on these models explore the impact of input uncertainties, and provide reliable quantification of uncertainties in their predictions. This minisymposium focuses on challenges and recent advances in uncertainty quantification (UQ) in chemical models and combustion computations. It brings together experts from a wide range of backgrounds working in computational combustion and interested in UQ, parameter estimation, and model assessment.

Organizer: Philip J. SmithUniversity of Utah, USA

Organizer: Michael FrenklachUniversity of California, Berkeley, USA

Organizer: Habib N. NajmSandia National Laboratories, USA

9:30-9:55 Furnace Design: Extrapolation of UncertaintyPhilip J. Smith and Sean Smith,

University of Utah, USA

10:00-10:25 Providing Structure to Experimental Data: A Large Scale Heterogeneous Database for Collaborative Model ValidationJames Oreluk, University of California,

Berkeley, USA



Tuesday, April 4

CP12Numerical Methods II9:30 AM-11:30 AMRoom:Salon 6 - Mezzanine Level

Chair: Patrick Pisciuneri, University of Pittsburgh, USA

9:30-9:45 A Variational Approach to Design a Numerical Scheme on an Arbitrary Moving Grid for N-Fluid Flow with Thermodynamic Consistency

Antoine Llor, Thibaud Vazquez-Gonzalez, and Christophe Fochesato, CEA, France

9:50-10:05 On the Suitability of Deconvolution to Capture Filtered Premixed Flames Structure and PropagationCedric C. Mehl, CentraleSupelec, France;

Jerome Idier, IRCCyN laboratory, France; Benoit Fiorina, École Centrale de Paris, France

10:10-10:25 Concept of Spectral Differentiation for Solving a Flow ModelBadr Alkahtani, King Saud University,

Saudia Arabia

10:30-10:45 Adaptive Numerical Solution of Advancing and Retreating Edge Flames in a New ConfigurationBen Shields, Carlos Pantano, and

Jonathan B. Freund, University of Illinois at Urbana-Champaign, USA

10:50-11:05 Dissipation Element Analysis of Premixed Spatial Evolving Jet FlamesDominik Denker and Antonio Attili,

RWTH Aachen University, Germany; Stefano Luca, King Abdullah University of Science & Technology (KAUST), Saudi Arabia; Fabrizio Bisetti, University of Texas at Austin, USA; Heinz Pitsch, RWTH Aachen University, Germany

11:10-11:25 Architecture-Aware Dynamic Repartitioning for Turbulent ReactorsPeyman Givi and Patrick Pisciuneri,

University of Pittsburgh, USA

Tuesday, April 4

MS6Model Validation for Solid Fuel Combustion from Experiments9:30 AM-11:30 AMRoom:Salon 5 - Mezzanine Level

Modeling solid fuel combustion systems is challenging due to the complex, interacting physics involved, the large range of scales that affect the results, but also due to a lack of detailed insights from experiments or numerical simulations. Detailed experiments are also required to validate the models developed from first principles. The present minisymposium aims at first providing an overview of validation experiments for different aspects of solid fuel combustion, from small-scale experiments through lab-scale flames to large scale boilers. The focus of the minisymposium is on lessons learned by modelers from the simulation of the respective experiments, where each talk is intended to start with a short presentation of the experiment as such. After a review of the modeling conducted, each session is intended to conclude on open research questions for the cases investigated - and on models that should be tested with these experiments. To ensure the link between modeling and experimentation, presenters have been invited to team up, so that each presentation shall include the relevant experimentalist.

Organizer: Oliver T. SteinUniversität Stuttgart, Germany

Organizer: Christian HasseTechnische Universität Bergakademie Freiberg, Germany

Organizer: Andreas KempfUniversität Duisburg-Essen, Germany

Organizer: Andreas KronenburgUniversität Stuttgart, Germany

Organizer: Perrine PepiotCornell University, USA

Organizer: Christopher ShaddixSandia National Laboratories, USA

Organizer: Hiroaki WatanabeKyushu University, Japan

9:30-9:55 Solid Fuel Jet Flame Experiments and SimulationsHiroaki Watanabe, Kyushu University,

Japan; Kazuki Tainaka, Central Research Institute of Electric Power Industry, Japan

10:00-10:25 1-D Flame Configuration for Validating Pulverized Coal Devolatilization and Oxidation ModelingMeng Xia, Philippe Scouflaire, and

Benoit Fiorina, École Centrale de Paris, France; Nasser Darabiha, CNRS, France

10:30-10:55 Modeling, Simulation and Validation of an Advanced Oxyfuel CombustorSamim Doost, Florian Ries, Robert

Knappstein, Francesca di Mare, Amsini Sadiki, Johannes Janicka, Lukas Becker, and Sebastian Bürkle, Technische Universität Darmstadt, Germany; Diego Zabrodiec, RWTH Aachen University, Germany; Steven Wagner, Benjamin Boehm, and Andreas Dreizler, Technische Universität Darmstadt, Germany; Reinhold Kneer, RWTH Aachen University, Germany

11:00-11:25 Biomass Pyrolysis in a Micro-Fluidized Bed: A Combined Experimental and Modeling StudyPerrine Pepiot and Himanshu Goyal,

Cornell University, USA; Guillain Mauviel, Anthony Dufour, and Liangyuan Jia, Université de Lorraine, France



Tuesday, April 4

CP14LES II9:30 AM-11:30 AMRoom:Salon 8 - Mezzanine Level

Chair: Jeffrey Labahn, Stanford University, USA

9:30-9:45 LES of Core Noise in a Combustor Nozzle SystemJeffrey D. O’Brien, Stanford University,

USA; Friedrich Bake, German Aerospace Center (DLR), Germany; Yu Lv and Matthias Ihme, Stanford University, USA

9:50-10:05 Large Eddy Simulation of Co2 Dilution in Premixed Swirling Oxy-Flames and Assessment of Radiation EffectsLorella Palluotto, EM2C Laboratory,

France; Ronan Vicquelin, Ecole Centrale Paris, France; Paul Jourdaine, Clément Mirat, and Thierry Schuller, EM2C Laboratory, France; Olivier Gicquel, Ecole Centrale Paris, France

10:10-10:25 LES Investigation of Fuel Effects on Lean Blow off (LBO) for a Realistic Two-Phase Flow CombustorJeffrey Labahn, Lucas Esclapez, and

Matthias Ihme, Stanford University, USA

10:30-10:45 LES-FDF with Hybrid Finite Rate and Flamelet Chemistry Modeling of a Piloted Turbulent Flame with Inhomogeneous InletsMartin Rieth, Universität Duisburg-Essen,

Germany; Suresh Menon, Georgia Institute of Technology, USA; Fabian Proch and Andreas Kempf, Universität Duisburg-Essen, Germany

10:50-11:05 Large Eddy Simulation of Non-Conventional Combustion RegimesZhiyi Li, Université Libre de Bruxelles,

Belgium; Alberto Cuoci, Politecnico di Milano, Italy; Amsini Sadiki, Technische Universität Darmstadt, Germany; Alessandro Parente, Université Libre de Bruxelles, Belgium

11:10-11:25 Large Eddy Simulation of Lifted Turbulent Flame Using Doubly Conditional Source-Term EstimationMohammad Mortada and Cecile B.

Devaud, University of Waterloo, Canada

Tuesday, April 4Lunch Break11:30 AM-1:00 PMAttendees on their own

MS7Uncertainty Quantification in Computational Combustion - Part II of III1:00 PM-3:00 PMRoom:Ballroom C - Lobby Level

For Part 1 see MS5 For Part 3 see MS9 Predictive combustion computations rely on calibrated and validated models. These models rely on parameters that are estimated either from experimental measurements or from theory/computations, and are, to some extent, uncertain. Accordingly, it is important that computational predictions based on these models explore the impact of input uncertainties, and provide reliable quantification of uncertainties in their predictions. This minisymposium focuses on challenges and recent advances in uncertainty quantification (UQ) in chemical models and combustion computations. It brings together experts from a wide range of backgrounds working in computational combustion and interested in UQ, parameter estimation, and model assessment.




1:00-1:25 Chemical Model Reduction Under UncertaintyHabib N. Najm, Sandia National

Laboratories, USA; Mauro Valorani and Riccardo Malpica Galassi, Università di Roma “La Sapienza”, Italy

Tuesday, April 4

CP13Kinetics I9:30 AM-11:30 AMRoom:Salon 7 - Mezzanine Level

Chair: Charles Westbrook, Lawrence Livermore National Laboratory, USA

9:30-9:45 Rapid Reduction of a Chemical Kinetic Model for the Combustion of the Pyrolysis Oil Surrogate Ethylene GlycolTorsten Methling, Trupti Kathrotia,

and Uwe Riedel, German Aerospace Center (DLR), Germany

9:50-10:05 A Reduced Chemical Mechanism for Kerosene via an RCCE-CSP MethodologyPanayiotis Koniavitis, W. P. Jones, and

Stelios Rigopoulos, Imperial College London, United Kingdom

10:10-10:25 Virtual Chemistry Applied to Pollutants Emission PredictionMélody Cailler, CNRS, CentraleSupélec,

Safran Tech, France; Nasser Darabiha, CNRS, France; Denis Veynante, CNRS, CentraleSupélec, France; Benoit Fiorina, École Centrale de Paris, France

10:30-10:45 Adjoint-Based Sensitivity of Ignition in Non-Premixed Turbulent FlowsJesse Capecelatro, University of

Michigan, USA; Jonathan B. Freund, University of Illinois at Urbana-Champaign, USA

10:50-11:05 Impact of Chemical Kinetic Model Reduction on Premixed Multi-Dimensional Flame CharacteristicsAaron J. Fillo and Kyle E. Niemeyer,

Oregon State University, USA

11:10-11:25 Effect of Mechanism Reduction on the Uncertainty Quantification of Chemical Kinetics for MILD CombustionMagnus Fürst, Université Libre

de Bruxelles, Belgium; Alessio Frassoldati, Politecnico di Milano, Italy; Alessandro Parente, Université Libre de Bruxelles, Belgium

continued on next page


1:30-1:55 Quantifying Variability in Sub-Models for LES of Reacting FlowsJoseph C. Oefelein, Guilhem Lacaze,

and Layal Hakim, Sandia National Laboratories, USA

2:00-2:25 Black Swans, Dragon Kings and the Science of Rare Events in Turbulent CombustionVenkat Raman and Malik Hassanaly,

University of Michigan, USA

2:30-2:55 Development of An UQ-Predictive Chemical Reaction Model for Syngas CombustionNadja Slavinskaya, Mehdi Abbasi,

Jan Hendrik Starcke, and Aziza Mirzayeva, German Aerospace Center (DLR), Germany; Wenyu Li, James Oreluk, Arun Hegde, Andrew Packard, and Michael Frenklach, University of California, Berkeley, USA; G. Gerasimov and O Shatalov, Moscow State University, Russia

Tuesday, April 4

MS8High Karlovitz Number Turbulent Combustion: Physics and Modeling Challenges - Part I of II1:00 PM-3:00 PMRoom:Salon 5 - Mezzanine Level

For Part 2 see MS10 Turbulent combustion in practical devices can occur in regimes – very large Reynolds and Karlovitz numbers – as yet not easily accessible to experimental or numerical investigations. Recent progress in direct numerical simulations (DNS) and advanced laser diagnostics provide us a brand new picture of flame structures under those extreme conditions. Due to the complex interactions between turbulence and chemistry, the structures, propagation and stabilization mechanisms of flames at strongly turbulent conditions are not fully understood, particularly for premixed flames in the broken reaction zones regime on the classical Borghi diagram. The frequent local extinction and re-ignition resulting from the turbulence-flame interactions can significantly alter the physico-chemical processes in those flames, which can modify the global combustion characteristics well beyond the conventional effects (e.g., flame wrinkling, strain/curvature, turbulence transport). Moreover, understanding the underlying physical processes in high-Re/high-Ka turbulent flames is a prerequisite for proposing high-fidelity models for those conditions. Therefore, this minisymposium aims at bringing together leading researchers who can showcase their latest research on physics and modelling aspects of high Ka flames and facilitate a conversation on tackling the gaps in understanding and modelling challenges inherent in these conditions.

Organizer: Xinyu ZhaoUniversity of Connecticut, USA

Organizer: Hemanth KollaSandia National Laboratories, USA

1:00-1:25 Distributions of Flow Topology and Enstrophy in Different Turbulent Premixed Combustion Regimes: A Direct Numerical Simulation InvestigationHong G. Im, King Abdullah University

of Science & Technology (KAUST), Saudi Arabia; Bill Papapostolou and Daniel Wacks, Newcastle University, United Kingdom; Markus Klein, Technische Universität Darmstadt, Germany; Nilanjan Chakraborty, Newcastle University, United Kingdom

1:30-1:55 High Karlovitz Turbulent Flames: Is-This Only a Laboratory/DNS Toy Problem?Luc Vervisch, INSA Rouen, France

2:00-2:25 Turbulence-Flame Interactions in High-Speed Premixed Reacting FlowsPeter Hamlington, University of

Colorado Boulder, USA; Alexei Poludnenko, Texas A&M University, USA

2:30-2:55 Dns of Turbulent Lean Methane-Air Piloted Jet Flames at High Karlovitz NumberHaiou Wang and Evatt R. Hawkes,

University of New South Wales, Australia; Jacqueline Chen, Sandia National Laboratories, USA



Tuesday, April 4

CP17LES III1:00 PM-3:00 PMRoom:Salon 8 - Mezzanine Level

Chair: Qing Wang, Stanford University, USA

1:00-1:15 Large Eddy Simulation of Supersonic Combustion in Cavity-Based ScramjetJiangheng Ruan, CNRS, France; Pascale

Domingo, CORIA, France; Guillaume Ribert, INSA de Rouen, France

1:20-1:35 Implicit Large Eddy Simulations of Auto-Ignition in a Temporally Evolving Mixing LayerArtur Tyliszczak, Agnieszka Wawrzak,

and Andrzej Boguslawski, Czestochowa University of Technology, Poland

1:40-1:55 Large Eddy Simulations of Explosion Deflagrating Flames Using a Dynamic Wrinkling FormulationPedro S. Volpiani, CNRS,

CentraleSupélec, France; Thomas Schmitt, Ecole Centrale Paris, France; Olivier Vermorel, CERFACS, France; Denis Veynante, Ecole Centrale Paris, France

2:00-2:15 An LES-PBE-PDF Approach for Predicting Soot Particle Size Distributions in a Turbulent Diffusion FlameFabian Sewerin and Stelios Rigopoulos,

Imperial College London, United Kingdom

2:20-2:35 Large Eddy Simulations of a Bluff-Body Stabilized FlameBifen Wu, Xinyu Zhao, Bikram

Chowdhury, and Baki Cetegen, University of Connecticut, USA

2:40-2:55 Large Eddy Simulation of the Inhomogeneous Inlet Jet Flame Using Regularized Deconvolution MethodQing Wang and Matthias Ihme, Stanford

University, USA

Coffee Break3:00 PM-3:30 PMRoom:Ballroom C Foyer - Lobby Level

Tuesday, April 4

CP16Kinetics II1:00 PM-3:00 PMRoom:Salon 7 - Mezzanine Level

Chair: Esteban Cisneros-Garibay, University of Illinois at Urbana-Champaign, USA

1:00-1:15 Propagation of Kinetic Uncertainty Through Surrogate Subspace in Turbulent Combustion SimulationsWeiqi Ji, Jiaxing Wang, Bin Yang, and

Zhuyin Ren, Tsinghua University, China

1:20-1:35 A Multipurpose Mechanism for Ethanol CombustionAlejandro Millán-Merino, Eduardo

Fernández-Tarrazo, and Mario Sánchez-Sanz, Universidad Carlos III de Madrid, Spain

1:40-1:55 Numerical Simulation of Counterflow Diffusion Flames of Methyl Decanoate Based on a Reduced MechanismFelipe C. Minuzzi, Federal University of

Rio Grande do Sul, Brazil; Jean Pinho, Federal Institute of Santa Catarina, Brazil; Alvaro De Bortoli, Federal University of Rio Grande do Sul, Brazil

2:00-2:15 pyMARS: A Open Software Package for Chemical KInetics Model ReductionParker Clayton and Kyle E. Niemeyer,

Oregon State University, USA

2:20-2:35 Performance of Nonstiff and Stiff Chemical Kinetics Integrators on Heterogeneous Processor ArchitecturesNicholas Curtis, University of

Connecticut, USA; Chris Stone, Computational Science and Engineering, LLC, USA; Chih-Jen Sung, University of Connecticut, USA; Kyle E. Niemeyer, Oregon State University, USA

2:40-2:55 Bayesian Analysis of Constrained Equilibrium Reduced Kinetics Model ParameterizationEsteban Cisneros-Garibay, Carlos

Pantano, and Jonathan B. Freund, University of Illinois at Urbana-Champaign, USA

Tuesday, April 4

CP15Turbulent Flames1:00 PM-3:00 PMRoom:Salon 6 - Mezzanine Level

Chair: Michael E. Mueller, Princeton University, USA

1:00-1:15 Generalized Turbulent Combustion Model for Multi-Modal CombustionMichael E. Mueller, Princeton University,

USA

1:20-1:35 Nox Formation in Turbulent Premixed Slot Flames with Mixture Inhomogeneity: A Numerical StudyStefano Luca, King Abdullah University

of Science & Technology (KAUST), Saudi Arabia; Antonio Attili, RWTH Aachen University, Germany; Fabrizio Bisetti, University of Texas at Austin, USA

1:40-1:55 Large Eddy Simulation of a Turbulent Swirling Premixed Flame Coupling the TFLES Model with a Dynamic Wrinkling FormulationPedro S. Volpiani, CNRS,

CentraleSupélec, France; Thomas Schmitt and Denis Veynante, Ecole Centrale Paris, France

2:00-2:15 Turbulent Flame Sub-Grid Scale Modeling with High-Order Spectral DifferenceLuc Vervisch, INSA Rouen, France;

Eurielle Bossennec and Guido Lodato, CORIA CNRS & INSA Rouen Normandie, France

2:20-2:35 Dynamic Mode Decomposition of Turbulent Non-Reacting and Reacting Nonpremixed JetsTemistocle Grenga, Jonathan F. Macart,

and Michael E. Mueller, Princeton University, USA

2:40-2:55 Transitional Behavior in the Regime from Lifted Flames to Mild FlamesChengyu Liu and Jian Zhang, Chinese

Academy of Sciences, China; Yanhong Ma, Beihang University, China


Tuesday, April 4

MS10High Karlovitz Number Turbulent Combustion: Physics and Modeling Challenges - Part II of II3:30 PM-5:30 PMRoom:Salon 5 - Mezzanine Level

For Part 1 see MS8 Turbulent combustion in practical devices can occur in regimes – very large Reynolds and Karlovitz numbers – as yet not easily accessible to experimental or numerical investigations. Recent progress in direct numerical simulations (DNS) and advanced laser diagnostics provide us a brand new picture of flame structures under those extreme conditions. Due to the complex interactions between turbulence and chemistry, the structures, propagation and stabilization mechanisms of flames at strongly turbulent conditions are not fully understood, particularly for premixed flames in the broken reaction zones regime on the classical Borghi diagram. The frequent local extinction and re-ignition resulting from the turbulence-flame interactions can significantly alter the physico-chemical processes in those flames, which can modify the global combustion characteristics well beyond the conventional effects (e.g., flame wrinkling, strain/curvature, turbulence transport). Moreover, understanding the underlying physical processes in high-Re/high-Ka turbulent flames is a prerequisite for proposing high-fidelity models for those conditions. Therefore, this minisymposium aims at bringing together leading researchers who can showcase their latest research on physics and modelling aspects of high Ka flames and facilitate a conversation on tackling the gaps in understanding and modelling challenges inherent in these conditions.

4:30-4:55 Uncertainties in Theoretical Chemical KineticsStephen Klippenstein, Argonne National

Laboratory, USA

5:00-5:25 Uniform Sampling of Feasible Set: A Hybrid Statistical-Deterministic Method of Uncertainty QuantificationWenyu Li, University of California,

Berkeley, USA

Tuesday, April 4

MS9Uncertainty Quantification in Computational Combustion - Part III of III3:30 PM-5:30 PMRoom:Ballroom C - Lobby Level

For Part 2 see MS7 Predictive combustion computations rely on calibrated and validated models. These models rely on parameters that are estimated either from experimental measurements or from theory/computations, and are, to some extent, uncertain. Accordingly, it is important that computational predictions based on these models explore the impact of input uncertainties, and provide reliable quantification of uncertainties in their predictions. This minisymposium focuses on challenges and recent advances in uncertainty quantification (UQ) in chemical models and combustion computations. It brings together experts from a wide range of backgrounds working in computational combustion and interested in UQ, parameter estimation, and model assessment.




3:30-3:55 Automatic Chemical Mechanism Generation using Optimized Rate RulesHeinz Pitsch and Liming Cai, RWTH

Aachen University, Germany

4:00-4:25 Sparse Resolutions to Inconsistent Datasets Via L1-MinimizationArun Hegde, University of California,

Berkeley, USA

continued in next column continued on next page


Tuesday, April 4

CP19Kinetics III3:30 PM-5:30 PMRoom:Salon 7 - Mezzanine Level

Chair: Kyle Niemeyer, Oregon State University,USA

3:30-3:45 Impact of Reduction of Chemistry on Soot Formation and Evolution in Laminar FlamesAgnes Livia Bodor, Politecnico di

Milano, Italy; Benedetta G. Franzelli, CNRS, France; Alessandro Stagni and Alberto Cuoci, Politecnico di Milano, Italy

3:50-4:05 Origins of a Hot Spot for Inhomogeneous End-Gas Autoignition in a Knocking SimulationHiroshi Terashima, Hokkaido University,

Japan; Akira Matsugi, National Institute of Advanced Industrial Science and Technology, Japan

4:10-4:25 A New Jet-Stirred Apparatus for Chemical Kinetics ExperimentsAshkan Davani and Paul Ronney,

University of Southern California, USA

4:30-4:45 Efficient Solution Strategy for the Use of Detailed Chemistry in High-Fidelity Simulations of Turbulent FlamesHao Wu and Matthias Ihme, Stanford

University, USA

4:50-5:05 Introducing ChemKED: A New Human and Machine-Readable Data Standard for Chemical Kinetics ExperimentsBryan W. Weber, University of

Connecticut, USA; Kyle E. Niemeyer, Oregon State University, USA

5:10-5:25 Towards Efficient Chemistry Calculations in Combustion Simulations Through Dynamic Adaptive AccelerationWenwen Xie, Zhen Lu, and Zhuyin Ren,

Tsinghua University, China

Tuesday, April 4

CP18Premixed Flames3:30 PM-5:30 PMRoom:Salon 6 - Mezzanine Level

Chair: Jose Grana-Otero, University of Kentucky, USA

3:30-3:45 Dynamics of Pulsating Planar Premixed FlamesJose Grana-Otero, University of

Kentucky, USA

3:50-4:05 The Role of Pressure Hessian in Premixed Turbulent CombustionUmair Ahmed, University of Manchester,

United Kingdom; Girish Nivarti, University of Cambridge, United Kingdom; Malgorzata Zimon, IBM Research, United Kingdom; Robert Prosser, University of Manchester, United Kingdom; Stewart Cant, University of Cambridge, United Kingdom

4:10-4:25 Scalar Transport and Damkoehler’s Second Hypothesis in the Thin Reaction Zones RegimeGirish Nivarti and Stewart Cant,


4:30-4:45 Three-Dimensional Flame-Flame Interaction Topology for Premixed Hydrocarbon FlamesShrey Trivedi, Ryan Griffiths, and

Stewart Cant, University of Cambridge, United Kingdom

4:50-5:05 Modelling of Premixed Flames in Progress-Variable Space Including Strain and Curvature EffectsAxel Zschutschke, Arne Scholtissek, and

Christian Hasse, Technische Universität Bergakademie Freiberg, Germany

5:10-5:25 Flame Structure and Chemiluminescence in Premixed FlamesJose Grana-Otero, University of

Kentucky, USA

Tuesday, April 4

MS10High Karlovitz Number Turbulent Combustion: Physics and Modeling Challenges - Part II of IIcontinued

Organizer: Xinyu ZhaoUniversity of Connecticut, USA

Organizer: Hemanth KollaSandia National Laboratories, USA

3:30-3:55 Transition of Combustion Mode During Flame-Flame Interaction and its Modeling ImplicationYuki Minamoto, Tokyo Institute of

Technology, Japan

4:00-4:25 Controlling Parameters in High Karlovitz Number Flames: Small Scales, Large Scales, and UniversalityGuillaume Blanquart, California

Institute of Technology, USA

4:30-4:55 A Priori and a Posteriori Study of a High Karlovitz Number Premixed Turbulent Jet ConfigurationKonstantin Kleinheinz, L. Berger,

and Antonio Attili, RWTH Aachen University, Germany; Haiou Wang and Evatt R. Hawkes, University of New South Wales, Australia; Heinz Pitsch, RWTH Aachen University, Germany

5:00-5:25 Low-Temperature Chemistry in Turbulent Premixed Dodecane FlamesMarc Day, Andrew Aspden, and John

B. Bell, Lawrence Berkeley National Laboratory, USA


Wednesday, April 5

IP3Dynamic Partitioning and Quantum Speedup for Turbulent Combustion Simulation8:15 AM-9:00 AMRoom:Ballroom C - Lobby Level

Chair: Jackie Chen, Sandia National Laboratories, USA

Within the past thirty years, a variety of subgrid scale closures have been developed for large eddy simulation (LES) of turbulent combustion. The filtered density function (FDF) is one of such closures and has proven very effective in a variety of applications. Despite its demonstrated capabilities, the computational cost associated with FDF can be expensive compared to other (more conventional) methods. This problem can be effectively alleviated by taking advantages of modern developments in computing and information science. A novel strategy is to couple an architecture aware graph partitioning algorithm with a dynamic (re)partitioning framework. This provides an optimal load balance, while minimizing the cost of data migration. Each of the partitions is treated via an entirely self-contained solver (in either Eulerian or Lagrangian contexts). The communication between the solvers is local, and shared information is limited to neighboring partitions. Quantum computing is also very promising for future LES via FDF. Recent developments in quantum enhanced measurements provide an algorithm that facilitates a quadratic speedup over classical FDF solvers. This demonstration identifies FDF as a viable problem to take advantage of speedups offered by future quantum computers.

Peyman GiviUniversity of Pittsburgh, USA


Wednesday, April 5



Closing Remarks8:10 AM-8:15 AMRoom:Ballroom C - Lobby Level

Tuesday, April 4

CP20LES IV3:30 PM-5:30 PMRoom:Salon 8 - Mezzanine Level

Chair: Yu Lv, Stanford University, USA

3:30-3:45 Sub-Grid Scale Modeling of the Equation of State for Fully Compressible Combustion LESGuillaume Ribert, INSA de Rouen,

France; Pascale Domingo, CORIA, France; Luc Vervisch, INSA Rouen, France

3:50-4:05 Application of Discontinuous Galerkin Methods for LES Predictions of Turbulent FlamesYu Lv and Matthias Ihme, Stanford

University, USA

4:10-4:25 Impact of Radiation Modeling in Large Eddy Simulation of a Turbulent Sooting Diffusion Ethylene-Air FlamePedro Rodrigues, Université Paris-

Saclay, France; Ronan Vicquelin, Ecole Centrale Paris, France; Benedetta G. Franzelli, CNRS, France; Olivier Gicquel and Nasser Darabiha, Ecole Centrale Paris, France

4:30-4:45 Impact of Numerical Discretization and Filter Shape on Large-Eddy Simulations of Turbulent Premixed FlamesAyaboe K. Edoh, University of California,

Los Angeles, USA

4:50-5:05 Temperature Consistency Preservation in Large Eddy Simulation-Filtered Mass Density Function (LES-FMDF) Methods for High-Speed FlowsLin Zhang, Jianhan Liang, Mingbo Sun,

and Hongbo Wang, National University of Defense Technology, China

5:10-5:25 The Filtered Wrinkled Flame (FWF) Model for Large-Eddy Simulation of Turbulent Premixed CombustionVincent R. Moureau, CORIA, France;

Renaud Mercier, Safran Tech, France; Benoit Fiorina, École Centrale de Paris, France


Wednesday, April 5

MS12Progress and Opportunities in Modeling and Simulations of Supercritical Combustion - Part I of II9:30 AM-11:30 AMRoom:Salon 5 - Mezzanine Level

For Part 2 see MS14 Over recent years, significant progress has been made in the fundamental understanding of supercritical combustion phenomena in rocket engines. The prevalent view as a high pressure liquid jet break-up into a droplet cloud was replaced with the view of a turbulent mixing process that should most appropriately be modeled as an Eulerian continuum. This understanding and the modeling have been canonized to the point that the main focus of the numerical tools lies on application to technical systems. However, several fundamental questions are currently being readdressed as the scope has been extended to other applications, including internal combustion engines and gas-turbines. Current investigations address interfacial phenomena and the transition between sub- and supercritical break-up modes, the description of mixing and phase transition in high-pressure environments. The study of bulk properties of supercritical fluids addresses the thermodynamic similarity to subcritical phase changes and implications for injection. Finally, numerical models are being investigated that account for the presence of surface tension forces at supercritical pressure. The purpose of this minisymposium is to provide an overview of the research progress, spanning the fundamental thermodynamic understanding, computational modeling, and applications. The symposium will be complemented by recent experimental investigation and identifying further research opportunities.

9:30-9:55 Prevention and Promotion of Flame Acceleration and Deflagration-to-Detonation TransitionV’yacheslav Akkerman, West Virginia

University, USA; Orlando Ugarte, University of Maryland, College Park, USA; Serdar Bilgili, West Virginia University, USA; Damir M. Valiev, Umeå University, Sweden

10:00-10:25 Flame Acceleration in Long Narrow Channels Enhanced by Compressibility EffectsVadim Kurdyumov, CIEMAT, Madrid,

Spain; Moshe Matalon, University of Illinois at Urbana-Champaign, USA

10:30-10:55 Formation and Structure of Accelerating Combustion WaveViatcheslav Bykov and Andrey

Koksharov, Karlsruhe Institute of Technology, Germany

11:00-11:25 Turbulence Effects on Detonation Propagation and StructureKun Luo, Tai Jin, and Jianren Fan,

Zhejiang University, China

Wednesday, April 5

MS11New Strategies towards Control of Flame Acceleration and DDT - Part I of II9:30 AM-11:30 AMRoom:Ballroom C - Lobby Level

For Part 2 see MS13 Combustion intensification by means of flame acceleration and deflagration-to-detonation transition (DDT) commands both practical relevance and fundamental interest. From the practical consideration, the DDT stands behind countless disasters such as explosions in power plants and mining accidents that claim hundreds of lives every year. On the other hand, the DDT can be employed, in the energetically cheapest manner, in advanced technologies such as micro-combustors and pulse-detonation engines of the next-generation hypersonic aircrafts. It is noted that combustion tubes are probably the most suitable geometry to attain and investigate flame acceleration and DDT that can occur because of wall friction, in built obstacles, combustion instabilities, flame-acoustic coupling, imposed and flame generated turbulence, as well as the interplay of all these effects. At present, there is no satisfactory agreement between various groups analyzing flame acceleration and DDT as well as between the approaches they imply. Within the proposed minisymposium we aim to consolidate the entire multi-discipline knowledgebase of combustion intensification followed by a detonation initiation, including that in combustion tubes; get rid of existing discrepancies, and develop the strategy for future works.

Organizer: V’yacheslav AkkermanWest Virginia University, USA



Wednesday, April 5

CP21Modeling Complexity I9:30 AM-11:30 AMRoom:Salon 6 - Mezzanine Level

Chair: Somesh P. Roy, Marquette University, USA

9:30-9:45 Eulerian-Lagrangian Simulation of Non-Spherical Biomass Particles in Turbulent FlowNing Guo, Tian Li, and Terese Lovas,

Norwegian University of Science and Technology, Norway

9:50-10:05 Eulerian-Lagrangian Simulation of Thermochemical Degradation of Thermally Thick Biomass ParticlesTian Li and Terese Lovas, Norwegian

University of Science and Technology, Norway

10:10-10:25 Collaborative Simulations and Experiments for Development and Uncertainty Quantification of a Reduced Char Oxidation and Gasification Model in Oxy-Coal Combustion ConditionsSalvatore Iavarone, Université Libre de

Bruxelles, Belgium; Benjamin Isaac, Sean Smith, and Philip J. Smith, University of Utah, USA; James Oreluk, Andrew Packard, and Michael Frenklach, University of California, Berkeley, USA; Alessandro Parente, Université Libre de Bruxelles, Belgium

10:30-10:45 Systematic Error Analysis and Error Reduction of Interpolation-Based Moment Methods (MOMIC/HMOM) for Statistical Soot ModelingAchim Wick, Manish Kumar, and Heinz

Pitsch, RWTH Aachen University, Germany

Organizer: Daniel BanutiStanford University, USA

Organizer: Matthias IhmeStanford University, USA

9:30-9:55 Interfacial and Bulk Thermodynamics in Supercritical CombustionDaniel Banuti, Peter C. Ma,

Muralikrishna Raju, and Matthias Ihme, Stanford University, USA

10:00-10:25 Thermodynamic, Dynamic and Structural Properties of Compressed Liquids and Supercritical FluidsDima Bolmatov, Brookhaven National

Laboratory, USA

10:30-10:55 Analytical / Computational Approach to Liquid Injection at Supercritical PressuresWilliam Sirignano, University of

California, Irvine, USA

11:00-11:25 Modeling of High Pressure Sprays and Combustion Based on Phase Equilibrium and Jet Theory with Thermal RadiationZongyu Yue and Rolf Reitz, University of

Wisconsin, Madison, USA

10:50-11:05 Improvements to Photon Monte Carlo Radiation Solver for Combustion SimulationsSomesh P. Roy, Marquette University,

USA; Steffen Weise, Technische Universität Bergakademie Freiberg, Germany; Ankur Gupta, FM Global, USA; Michael Modest, University of California, Merced, USA; Christian Hasse, Technische Universität Bergakademie Freiberg, Germany; Daniel C. Haworth, Pennsylvania State University, USA

11:10-11:25 Scalar Gradient Statistics for Regime Independent ModelingHemanth Kolla, Sandia National

Laboratories, USA; Hasret Turkeri and Xinyu Zhao, University of Connecticut, USA



Wednesday, April 5

CP23Practical Systems I9:30 AM-11:30 AMRoom:Salon 8 - Mezzanine Level

Chair: Jeffrey Santner, Argonne National Laboratory, USA

9:30-9:45 Soot Formation Prediction of the Combustion Field of 4 KW Pulverized Coal Jet Burner by the Large Eddy Simulation with the Tabulated-Devolatilization-Process (TDP) ModelNozomu Hashimoto and Hiroyasu

Takahashi, Hokkaido University, Japan; Hiroaki Watanabe, Kyushu University, Japan; Ryoichi Kurose, Kyoto University, Japan; Osamu Fujita, Hokkaido University, Japan

9:50-10:05 Turbulent Reacting Hydrogen-Enriched Methane-Oxy Flames in a Swirl-Stabilized Gas Turbine CombustorMedhat A. Nemitallah, Mohamed Habib,

Syed Said, Mansur Aliyu, and Sherif Seif Eldin, King Fahd University of Petroleum and Minerals, Saudi Arabia

10:10-10:25 Dynamics of a Transcritical Coaxial Flame Submitted to Fuel Injection-Rate Modulations: Analysis of the Generation of Heat-Release Rate Unsteadiness and Low-Order ModelingRobin Nez, CNRS, CentraleSupélec,

France; Thomas Schmitt, Ecole Centrale Paris, France; Manuel Gonzalez-Flesca, Université Paris-Saclay and CNES DLA, France; Sébastien Candel, Université Paris-Saclay, France; Sébastien Ducruix, EM2C Laboratory, France

10:50-11:05 Direct Numerical Simulation of Particle Burning for Pulverized Coal CombustionOliver T. Stein, Giovanni-Luigi Tufano,

and Andreas Kronenburg, Universität Stuttgart, Germany; Martin Rieth and Andreas Kempf, Universität Duisburg-Essen, Germany; Michele Vascellari and Christian Hasse, Technische Universität Bergakademie Freiberg, Germany

11:10-11:25 Direct Numerical Simulation of Two-Phase Flows with Phase Change in Subcritical and Supercritical RegimesDavy Nayigizente, EM2C Laboratory,

France; Thomas Schmitt, Ecole Centrale Paris, France; Sébastien Ducruix, EM2C Laboratory, France

Wednesday, April 5

CP22DNS I9:30 AM-11:30 AMRoom:Salon 7 - Mezzanine Level

Chair: Aditya Konduri, Sandia National Laboratories, USA

9:30-9:45 Direct Numerical Simulation of Premixed Turbulent Jet Flames at High Reynolds NumberAntonio Attili, RWTH Aachen

University, Germany; Stefano Luca, King Abdullah University of Science & Technology (KAUST), Saudi Arabia; Fabrizio Bisetti, University of Texas at Austin, USA

9:50-10:05 Direct Numerical Simulations of Spherically Expanding Turbulent Premixed FlamesRomain Buttay, Stefano Luca, and Ravi

Samtaney, King Abdullah University of Science & Technology (KAUST), Saudi Arabia; Antonio Attili, RWTH Aachen University, Germany; Fabrizio Bisetti, University of Texas at Austin, USA

10:10-10:25 Direct Numerical Simulation of Flame Stabilization over a Rectangular Cavity with Compressibility EffectsAditya Konduri, Sandia National

Laboratories, USA; Andreas Rauch, University of Virginia, USA; Hemanth Kolla, Sandia National Laboratories, USA; Harsha Chelliah, University of Virginia, USA; Jacqueline Chen, Sandia National Laboratories, USA

10:30-10:45 Direct Numerical Simulations of Forced Ignition Behind a Backward Facing Step in Subsonic FlowAlex Krisman, Aditya Konduri, and

Jacqueline Chen, Sandia National Laboratories, USA



1:00-1:25 DDT in Channels with Tightly Spaced ObstaclesDamir M. Valiev, Umeå University,

Sweden; Orlando Ugarte, University of Maryland, College Park, USA; V’yacheslav Akkerman, West Virginia University, USA

1:30-1:55 Formation and Structure of Quasi-Detonation Oblique Reaction Front in Annular ChannelMike Kuznetsov and Jorge Yanez,

Karlsruhe Institute of Technology, Germany

2:00-2:25 Diffusion Flames and Diffusion Flame-Streets in Three Dimensional Micro-ChannelsShikhar Mohan and Moshe Matalon,

University of Illinois at Urbana-Champaign, USA

2:30-2:55 Analytical and Computational Description of a Coalmine Fire ScenarioSinan Demir, West Virginia University,

USA; Hayri Sezer and Ali S. Rangwala, Worcester Polytechnic Institute, USA; V’yacheslav Akkerman, West Virginia University, USA

Wednesday, April 5

MS13New Strategies towards Control of Flame Acceleration and DDT - Part II of II1:00 PM-3:00 PMRoom:Ballroom C - Lobby Level

For Part 1 see MS11 Combustion intensification by means of flame acceleration and deflagration-to-detonation transition (DDT) commands both practical relevance and fundamental interest. From the practical consideration, the DDT stands behind countless disasters such as explosions in power plants and mining accidents that claim hundreds of lives every year. On the other hand, the DDT can be employed, in the energetically cheapest manner, in advanced technologies such as micro-combustors and pulse detonation engines of the next-generation hypersonic aircrafts. It is noted that combustion tubes are probably the most suitable geometry to attain and investigate flame acceleration and DDT that can occur because of wall friction, in-built obstacles, combustion instabilities, flame-acoustic coupling, imposed and flame generated turbulence, as well as the interplay of all these effects. At present, there is no satisfactory agreement between various groups analyzing flame acceleration and DDT as well as between the approaches they imply. Within the proposed minisymposium we aim to consolidate the entire multi-discipline knowledgebase of combustion intensification followed by a detonation initiation, including that in combustion tubes; get rid of existing discrepancies, and develop the strategy for future works.

Organizer: V’yacheslav AkkermanWest Virginia University, USA

10:30-10:45 Numerical Investigation of Flame Flashback in an Ethylene-Fueled Scramjet Combustor at Mach 5.5 Flight ConditionMingbo Sun, Jinshui Wu, Xingda Cui,

Hongbo Wang, and Jianhan Liang, National University of Defense Technology, China

10:50-11:05 Numerical Study on Combustion Structure in a Cavity-Based Supersonic CombustorHongbo Wang, Mingbo Sun, Chaoyang

Liu, and Peibo Li, National University of Defense Technology, China

11:10-11:25 A Numerical Study of Hot Spot Ignition at Rapid Compression Machine ConditionsJeffrey Santner, Argonne National

Laboratory, USA

Lunch Break11:30 AM-1:00 PMAttendees on their own



Wednesday, April 5

CP24DNS II1:00 PM-2:40 PMRoom:Salon 6 - Mezzanine Level

Chair: Girish Nivarti, University of Cambridge, United Kingdom

1:00-1:15 Comparisons of Flame Surface Density Measurements with Direct Numerical Simulations of a Lean Methane-Air Flame in High-Intensity TurbulenceGirish Nivarti, University of

Cambridge, United Kingdom; Ben Thorne, University of Leeds, United Kingdom; Stewart Cant, University of Cambridge, United Kingdom; Malcolm Lawes and Derek Bradley, University of Leeds, United Kingdom

1:20-1:35 Direct Numerical Simulations of Dimethyl-Ether (DME)/Air Mixture Auto-Ignition with Temperature and Velocity FluctuationsXiao Xu and Bok Jik Lee, King Abdullah

University of Science & Technology (KAUST), Saudi Arabia; Ramanan Sankaran, Oak Ridge National Laboratory, USA; Francisco Perez and Hong Im, King Abdullah University of Science & Technology (KAUST), Saudi Arabia

1:40-1:55 A New Jet-Stirred Apparatus for Turbulent Premixed Flame ExperimentsAshkan Davani and Paul Ronney,

University of Southern California, USA

2:00-2:15 Three-Dimensional Linear Eddy Modelling of Turbulent Hydrogen Jet Flames in Co-FlowFredrik Grøvdal, Norwegian University

of Science and Technology, Norway; Sigurd Sannan, SINTEF Energy Research, Norway; Alan Kerstein, Consultant, USA; J.Y. Chen, University of California, Berkeley, USA; Terese Lovas, Norwegian University of Science and Technology, Norway

2:20-2:35 Combustion Simulation of Transportation Package Performance in Severe, Long Duration Fire Using Computational Fluid Dynamics ToolsYang Sui, Nuclear Waste Management

Organization, Canada

Organizer: Matthias IhmeStanford University, USA

1:00-1:25 Diffuse Interface Transcritical Flames Models: A ComparisonVincent Giovangigli, CMAP, Ecole

Polytechnique, France; Lionel Matuszewski and Pierre Gaillard, ONERA, France

1:30-1:55 Experimental Test Ccases for Modelling Supercritical Combustion in Rocket EnginesJustin Hardi, Scott Beinke, Dmitry

Suslov, and Michael Oschwald, German Aerospace Center (DLR), Germany

2:00-2:25 Modelling of a Coaxial Lox/gh2 Injection Element under High Frequency Transverse Acoustic Velocity ForcingScott Beinke, German Aerospace Center

(DLR), Germany; Daniel Banuti, Stanford University, USA; Justin Hardi, Sebastian Karl, and Michael Oschwald, German Aerospace Center (DLR), Germany; Bassam Dally, The University of Adelaide, Australia

2:30-2:55 Robust Treatment of Thermodynamic Nonlinearities in the Simulation of Transcritical FlowsGuilhem Lacaze and Anthony Ruiz,

Sandia National Laboratories, USA; Thomas Schmitt, Ecole Centrale Paris, France; Joseph C. Oefelein, Sandia National Laboratories, USA

Wednesday, April 5

MS14Progress and Opportunities in Modeling and Simulations of Supercritical Combustion - Part II of II1:00 PM-3:00 PMRoom:Salon 5 - Mezzanine Level

For Part 1 see MS12 Over recent years, significant progress has been made in the fundamental understanding of supercritical combustion phenomena in rocket engines. The prevalent view as a high pressure liquid jet break-up into a droplet cloud was replaced with the view of a turbulent mixing process that should most appropriately be modeled as an Eulerian continuum. This understanding and the modeling have been canonized to the point that the main focus of the numerical tools lies on application to technical systems. However, several fundamental questions are currently being readdressed as the scope has been extended to other applications, including internal combustion engines and gas-turbines. Current investigations address interfacial phenomena and the transition between sub- and supercritical break-up modes, the description of mixing and phase transition in high-pressure environments. The study of bulk properties of supercritical fluids addresses the thermodynamic similarity to subcritical phase changes and implications for injection. Finally, numerical models are being investigated that account for the presence of surface tension forces at supercritical pressure. The purpose of this minisymposium is to provide an overview of the research progress, spanning the fundamental thermodynamic understanding, computational modeling, and applications. The symposium will be complemented by recent experimental investigation and identifying further research opportunities.

Organizer: Daniel BanutiStanford University, USA



Wednesday, April 5

CP25Practical Systems II1:00 PM-3:00 PMRoom:Salon 7 - Mezzanine Level

Chair: Sadaf Sobhani, Stanford University, USA

1:00-1:15 Modeling of Light-Round in An Annular Combustor Operating under Perfectly Premixed ConditionsMaxime Philip, Ronan Vicquelin, and

Thomas Schmitt, Ecole Centrale Paris, France; Sébastien Candel, CNRS, CentraleSupélec, France

1:20-1:35 Detailed Investigation of the Two-Phase Reacting Flow in An Aeronautical Test RigAymeric Vié and Benedetta G. Franzelli,

CNRS, France

1:40-1:55 CFD Modeling of Water Mist Suppression of Solid Combustible Fires Using FirefoamNing Ren, Hong-Zeng Yu, Karl Meredith,

Ankur Gupta, and Yi Wang, FM Global, USA

2:00-2:15 Numerical Investigation and Optimization of Porous Media BurnersSadaf Sobhani, Danyal Mohaddes, and

Matthias Ihme, Stanford University, USA

2:20-2:35 Numerical Analysis of the Lagrangian Particle Transport of a Confined Stage Can CombustorDaniel Mira and Oriol Lehmkuhl,

Barcelona Supercomputing Center, Spain; Enric I. Mahiques and Lukasz Panek, Siemens AG, Germany; Mariano Vazquez and Guillaume Houzeaux, Barcelona Supercomputing Center, Spain

2:40-2:55 Numerical Simulation on Lean Premixed High Swirl Flame FlashbackYihao Tang, Malik Hassanaly, and Venkat

Raman, University of Michigan, USA

Wednesday, April 5

CP26Modeling Complexity II1:00 PM-3:00 PMRoom:Salon 8 - Mezzanine Level

Chair: Bruce A. Perry, Princeton University, USA

1:00-1:15 A Combination Between Two Semi-Analytical Method Called “Singularly Perturbed Homotopy Analysis Method, (spham)” Applied to Combustion of Spray Fuel DropletsOphir Nave, Ben Gurion University

Negev, Israel

1:20-1:35 Characteristics of a Partial Premixed Bluff Body Low NOx BurnerChristoph Meraner, Norwegian

University of Science and Technology, Norway; Mario Ditaranto, SINTEF Energy Research, Norway; Terese Lovas, Norwegian University of Science and Technology, Norway

1:40-1:55 Adequate Techniques for the Practical Computation of Optimal EstimatorsLukas Berger and Heinz Pitsch, RWTH

Aachen University, Germany; Michael E. Mueller, Princeton University, USA

2:00-2:15 Mode Determination for Combustion Modeling in Partially Premixed Turbulent FlamesBruce A. Perry and Michael E. Mueller,

Princeton University, USA

2:20-2:35 Dynamics of Combustion Systems Using Lyapunov AnalysisMalik Hassanaly and Venkat Raman,

University of Michigan, USA

2:40-2:55 Stochastic Modeling of CombustionSalam Khan, Alabama A&M University,

USA


Notes


NC17 Abstracts

Abstracts are printed as submitted by the author.

32 NC17 Abstracts

IP1

Modeling Flame Holes in Turbulent NonpremixedFlows

Turbulent diffusion flames can be quenched in regions ofhigh strain owing to increased heat loss away from the re-action zone. These chemically inert regions are sometimescalled flame holes (Dold et al. 1991). Turbulent flameswith extinction are relevant in modern combustors wherethe flame temperature is kept low to reduce pollutant for-mation or in lifted jet flames used for thermal protectionof the burner. Modeling the dynamical behavior of flameholes, without recourse to a detailed chemical-transportdescription, requires new numerical methods that describethe evolution in time of the flame boundary (or rim) on themoving stoichiometric surface. The kinematics of the flamerim is normally approximated as those of a two-dimensionaledge flame whose speed of propagation is controlled by thelocal strain. In mathematical terms, the challenge is theefficient numerical evolution of a state field defined on atwo-manifold (of varying shape, and possibly multiply con-nected). In this talk, I will describe recent progress on thenumerical and physical modeling of flame holes as it ap-plies to turbulent nonpremixed flames. Special emphasisof current research is to achieve high-order of accuracy,flexibility, and robustness, while maintaining relatively lowcomputational cost.

Carlos PantanoMechanical Science and EngineeringUniversity of Illinois at [email protected]

IP2

Progress and Challenges in Simulating CombustionSystems with Realistic Chemistry

The vital role of simulations and computational insights inreducing pollutant emissions, designing better engines andbetter fuels, and assessing the technical and economic via-bility of radically different combustion technologies, is nowclearly established. A key enabling step is the developmentof computational approaches that allow our increasinglydetailed knowledge of the chemical kinetics of realistic fueloxidation to be applied to the modeling and simulation ofcombustion reactors. In this talk, I will briefly review thechallenges associated with the integration of detailed chem-ical kinetics in reactive flow simulations. I will then discussthe progress we have made in the analysis and reductionof complex kinetic networks, with a focus on graph-basedtechniques and the characteristics of the stand-alone re-duced models they typically generate. Using Large-EddySimulations of turbulent flames as case study, I will showhow these techniques are enhanced through careful integra-tion and coupling with CFD tools, wherein the flow char-acteristics adaptively inform the reduced chemical modelto be used. I will conclude on the remaining challenges stillto overcome, and potential avenues to do so.

Perrine PepiotCornell [email protected]

IP3

Dynamic Partitioning and Quantum Speedup forTurbulent Combustion Simulation

Within the past thirty years, a variety of subgrid scale clo-sures have been developed for large eddy simulation (LES)

of turbulent combustion. The filtered density function(FDF) is one of such closures and has proven very effec-tive in a variety of applications. Despite its demonstratedcapabilities, the computational cost associated with FDFcan be expensive compared to other (more conventional)methods. This problem can be effectively alleviated by tak-ing advantages of modern developments in computing andinformation science. A novel strategy is to couple an archi-tecture aware graph partitioning algorithm with a dynamic(re)partitioning framework. This provides an optimal loadbalance, while minimizing the cost of data migration. Eachof the partitions is treated via an entirely self-containedsolver (in either Eulerian or Lagrangian contexts). Thecommunication between the solvers is local, and shared in-formation is limited to neighboring partitions. Quantumcomputing is also very promising for future LES via FDF.Recent developments in quantum enhanced measurementsprovide an algorithm that facilitates a quadratic speedupover classical FDF solvers. This demonstration identifiesFDF as a viable problem to take advantage of speedupsoffered by future quantum computers.

Peyman GiviUniversity of Pittsburgh, [email protected]

CP1

High Explosive Performance Modeling Using thePseudo-Reaction Zone Energy Release Model inProgrammed Burn

Programmed Burn (PB) methods were developed to cal-culate timing and detonation energy delivery in high ex-plosive (HE) engineering systems without resolving the re-action zone length and time scales. These methods pre-compute the detonation wave motion, triggering energy re-lease only upon the wave’s arrival. Given the primary aimof accurately describing the energy delivery to surroundingmaterials, the PB methodology avoids resolving the deto-nation reaction zone required in reactive burn. AdvancedPB methods use a surface evolution model known as Det-onation Shock Dynamics (DSD) to provide time-of-arrivaland front shape information throughout the geometry ofinterest. As the timing and energy release components areweakly coupled, the success of the PB method relies on theenergy release rate being optimally synced to the DSD sur-face wave motion. We will detail a calibration methodologyof the Pseudo-Reaction Zone (PRZ) energy release modelthat achieves this aim, and apply it to the plastic-bondedHEs PBX 9501 and 9502. The PRZ model is defined bya two-step reaction rate dependent on the surface normaldetonation velocity provided by DSD (Wescott, 2007). Thecalibration procedure compares multi-dimensional simula-tions of detonations in 2D axisymmetric rate-sticks andplanar slab geometries based on the PRZ rate law to theequivalent DSD-generated steady-state front shapes andphase velocities. We also discuss strengths and limitationsof the DSD/PRZ energy delivery model.

Carlos Chiquete, Mark Short, Chad Meyer, James QuirkLos Alamos National [email protected], [email protected], [email protected],[email protected]

CP1

Mesoscale Simulations of Energetic Materials Us-ing Density-Based Kinetics

In this work we present results for the initiation of det-

NC17 Abstracts 33

onations in energetic materials through power depositiondue to pore collapse. We solve the reactive Euler equations,with the energy equation augmented by a power depositionterm. The deposition term is based on previous results ofpore collapse at the microscale, modelled at the macroscaleas hot-spots. We assume a one-step kinetic model. Previ-ous results used Arrhenius kinetics; however, late time so-lutions developed instabilities, a well-known problem whenusing temperature-based kinetics. Therefore in this workwe replace the Arrhenius kinetics with one based on den-sity. Simulation results show that a critical size of thehot-spots exists. If the hot-spots exceed the critical size,direct initiation of detonation results. We also carry outtwo-dimensional simulations, where the microstructure isgenerated by a random packing code, developed specifi-cally for packing energetic crystals. The crystals are thenseeding by randomly placing hot-spots based on varyingvoid content. Go-no go results as a function of shock pres-sure are presented.

Thomas JacksonUniversity of [email protected]

Ju ZhangFlorida Institute of [email protected]

CP1

Numerical Simulation of Detonation Propagationin Practical Geometries

Rotating detonation engines (RDEs) are re-emerging asone approach to increasing efficiency of conventional gasturbines. The pressure gain associated with such devicescan be used to derive extra work. The development of ro-bust RDEs depend on the design of fuel injectors that canwithstand detonation conditions while preventing backflowof combustion products into the feedline. In this regard,the availability of numerical simulation tools that can cap-ture detonation wave propagation through incompletelymixed fuel and air will directly benefit RDE development.Here, a high fidelity finite volume LES based Navier-Stokessolver is formulated for detonation applications on unstruc-tured grids, using the OpenFOAM framework. A detailedchemistry representation is used to describe detonations.The method is applied to complex flow geometries thatreplicate the main features of the injection region in a prac-tical RDE. Results obtained using this computational toolwill be compared to DNS data from an in-house code fordetonation based flows on structured grids, for validationpurposes and model optimization. Numerical and model-ing issues related to such configurations will be discussed.

Damien Masselot, Takuma Sato, Venkat RamanUniversity of [email protected], [email protected], [email protected]

CP1

Condensed-Phase Oblique Detonation Interactionwith a Rigid Wall

We examine the wave reflection patterns generated by theinteraction of a detonation in a condensed phase explosiveimpacting obliquely onto a rigid wall. The computationalapproach uses a shock-fit methodology (A. Henrick, Ph.D.Thesis, Univ. Notre Dame, 2008; Aslam and Romick, 15thDetonation Symp., 2014) with a second-order finite volume

algorithm. We look at the reflection patterns created byan instantaneous reaction Chapman-Jouguet detonation,compared with those of a small, resolved heat release det-onation (Bdzil, J. Fluid Mech., 1981), where the first partof the reaction is instantaneous, but the second has a finitelength scale. We compare the results of the computationswith an asymptotic study recently conducted by Bdzil andShort (J. Fluid Mech., 2016, to appear) for small obliquedetonation incident angles.

Mark ShortLos Alamos National [email protected]

John BdzilUniversity of Illinois at [email protected]

Carlos Chiquete, Chad MeyerLos Alamos National [email protected], [email protected]

CP1

Modeling of Aluminum Combustion in An Oxidiz-ing Environment with the Gibbs Formulation

We present a model for aluminum combustion in an oxidiz-ing enviroment that employs the newly-developed Gibbsformulation, which presumes a single local equilibriumstress tensor and temperature at each point in the ma-terial. This multi-component formulation considers solidand liquid phases of aluminum and its oxide and the gasphase of aluminum, oxygen, and nitrogen. Phase changesand exothermic reactions are characterized as reactions orphase change. The order parameters that are often in-voked in similar models are simply the mass fractions ofthe component species. Each change process has its indi-vidual reaction rate. The Maxwell-Stefan model is used fordiffusion. In oxidizing environment, pre-heated meso-scalealuminum slab partially coated with its oxide is heated,and different ignition transients are observed when the ox-ide concentration in the layer iv varied; the more aluminumoxide concentration in the layer, the lower the magnitude ofthe observed thermal spike near the layer during ignition.

D. Scott StewartUniversity of IllinoisDept of Theor & Applied [email protected]

CP1

A DSD Model for Converging Detonations

We derive the detonation shock dynamics (DSD)regularity-condition with a simple expansion of the Hugo-niot equation for a general equation of state. We explicitlyintegrate the regularity-condition for a JWL equation ofstate with a quadratic expansion about the sonic specificvolume around the ZND state for a converging detona-tion with a symmetrical geometry. We also numericallyintegrate the regularity-condition without approximationand obtained consistent results. The integral curves agreewith the data from direct-numerical-simulations. In ad-dition, we have calibrated a detonation front evolution-equation for a practical HE materiel. A particle-based DSDfront tracker produces detonation front geometries closelymatching the DNS data for both converging and divergingwaves using this evolution equation. Thus, we concludethat the detonation-shock-dynamics can be used for mod-

34 NC17 Abstracts

elling a converging detonation as well as for a divergingdetonation.

Jin Yao, Laurence E. Fried, Peter A. VitelloLawrence Livermore National [email protected], [email protected], [email protected]

CP2

A Computational Study of Ionic Wind Effectson Dynamics of Nonpremixed Counterflow FlamesSubjected to DC Electric Fields

Previous experimental studies reported significant effectsof the imposed electric field on the dynamics and structureof the flames. However, the role of the ionic wind gener-ated by the applied electric field needs further investiga-tion in order to provide fundamental understanding of thecomplex interactions of the electric fields and the flame-generated ions and electrons. In this study, high fidelitysimulations were performed to describe the effects of DCelectric fields on the behavior of nonpremixed counterflowflames with an emphasis on the modification of the ve-locity field caused by the ionic wind. The distribution ofthe charged species, electric field and current is computedbased on detailed two-dimensional numerical simulationsusing approaches similar to previous studies. The abilityof the model to predict the flame behavior is assessed bycomparing to available experimental measurements. Re-sults show that the presence of the electric field affectsthe strain rate and the location of the reaction zone. Themovement of positive and negative ions in opposite direc-tions towards the cathode and anode, respectively, gener-ates a bidirectional ionic wind, which decreases the flowlocal velocity. As the majority of ions are positive, theflame is moved toward the cathode. An interpretation ofthe stabilization mechanism of the flame under a bias volt-age is proposed based on an analysis of the current-voltagecharacteristics.

Memdouh BelhiClean Combustion Research Center, King AbdullahUniversityof Science and Technology (KAUST), Saudi [email protected]

Bok Jik Lee, Hong G. ImKing Abdullah University of Science and [email protected], [email protected]

CP2

Simulation of Plasma Initiation in Liquid Medium

In spite of the great deal of research emphasized on applica-tion of plasma in liquids, only a limited number of reportedworks have focused on the understanding of the underly-ing physics. In the current work, an attempt is made topresent a mathematical model to describe the initial stageof plasma discharge formation in a liquid medium. Themodel is based on a density based compressible solver solv-ing for the electrical field, momentum, energy and speciesconservation together with plasma reaction kinetics to re-solve the inter coupled physic-chemical processes. Threedifferent electric body forces including the ordinary elec-trostatic force, force acting on an inhomogeneous dielectricand force appearing due to electric field gradient are con-sidered. The multiphase effects are also considered by in-cluding a multi-fluid flow model, surface tension model to-gether with a special treatment of interfacial electric forces.The comprehensive model is able to provide insight on the

role of different dielectrics, interface location and appliedelectric pulse profile.

Ali Charchi Aghdam, Tanvir FaroukUniversity of South [email protected], [email protected]

CP2

DNS of Partially Premixed Mild Combustion

DNSs of partially premixed MILD combustion have beenperformed in the present work by extending the method-ology of Minamoto et al. (CST 186 1075-1096 (2014)) toinclude spatial variation of the mixture fraction, Z. Threedifferent cases were performed by varying in a first step theratio of length scales between the initial progress variable,c, field and the Z field from Lc/LZ < 1 to Lc/LZ ≈ 1 andin a second step by increasing the dilution level of oxidizerwith flue gases. The initial turbulence field for all cases iskept the same and the chemical mechanism used is basedon SMOOKE methane-air mechanism which is extendedto include OH* chemistry. The inclusion of OH* chemistrywill allow to finely distinguish regions of actual heat releasein MILD combustion from OH in the recirculating exhaustgas. Preliminary results have shown that reactions zonespresent a complex morphology, extremely different fromclassical combustion with a deeply convoluted aspects andhigh interaction between reaction zones. Additional anal-ysis highlighted that reactions were occurring mostly inlean mixture with the reaction zones seemingly wrappedaround pockets of rich mixture. Furthermore, it was ob-served that decreasing the oxygen level leads to reactionsoccurring over larger regions in the physical domain. Fu-ture work will be devoted to further qualify the structureof the reaction zones and assess the suitability of OH* toindicate heat release in MILD combustion.

Nguyen Anh Khoa Doan, Nedunchezhian SwaminathanUniversity of [email protected], [email protected]

Yuki MinamotoTokyo Institute of [email protected]

CP2

A Spectral Deferred Correction Strategy for LowMach Number Reacting Flows Subject to ElectricFields

We propose an algorithm for low Mach number reactingflows that includes the chemical production and electri-cal field forcing of charged species in the flame zone. Thework is an extension of a multi-implicit spectral deferredcorrection (MISDC) algorithm that is designed to advancethe solution in time at scales associated with the advectivetransport, and is applicable to cases where local separationsin net charge give rise to dielectric relaxations and nontriv-ial interactions with externally applied electric field. In thescheme diffusion, reactions, and dielectric relaxation termsare stiff relative to advection, and interact with each otherstrongly. The iterative time-stepping approach efficientlycouples all the terms, and exhibits second-order conver-gence in space and time. The algorithm is amenable to one-, two- and three-dimensional applications, and has beenimplemented in the context of a block-structured adaptivemesh refinement framework. We will present details of themethod and show examples of its performance on a range

NC17 Abstracts 35

of idealized and practical applications.

Valentina RicchiutiUniversity of California Irvine, MAE DepartmentLawrence Berkeley National [email protected]

Marc DayLawrence Berleley National [email protected]

CP2

Simulating Interactions of Detonation, IonizationChemistry, and Magnetohydrodynamics

Oxyfuel combustion is a strategy to remove NOx emis-sions from combustion-based power generation. However,the resulting high temperatures incur material challengesfor gas turbine technology. Detonation-driven flow througha magnetohydrodynamic (MHD) generator offers a poten-tial solution by directly extracting power from conductivefluid flow via the Lorentz force, removing immersed mov-ing components unable to withstand high temperatures.In addition, detonation cycles improve thermodynamic ef-ficiency. Modeling these coupled systems requires the si-multaneous consideration of compressible flow, chemicalreactions, and magnetic field interaction. To tackle thischallenge, a Riemann solver, implicit ordinary differentialequation integrators, and a Galerkin finite-element solverare coupled to solve Euler’s equations, stiff chemical kinet-ics equations, and decoupled Maxwell’s equations. Eachsolver will first be verified and validated separately, andthe coupled system validated with literature results andexperimental data. Simulations of hydrogen and methaneoxyfuel combustion will be performed over a range of con-ditions to determine power extraction and emissions. Inaddition, seed particles are typically necessary to increasethe fluids electrical conductivity through ionization; theimpact of seed composition and quantity will be assessed.Results will provide insight into the complex, and possiblyadverse, interactions between detonation, ionization, andMHD effects.

Matthew F. Zaiger, David Blunck, Kyle E. NiemeyerOregon State [email protected], [email protected],[email protected]

CP3

The Laminar Flamelet Model Combined with Col-lision Porosity Distance Algorithm Applied to Ac-cidental Explosion Modelling

This work presents a novel implementation of the PorosityDistributed Resistance (PDR) model coupled with a struc-tured 3D Navier-Stokes solver and Flamelet combustionmodel. The geometry is represented by porosities that arecomputed by calculating the minimum distance betweentwo convex sets. The GilbertJohnsonKeerthi (GJK) dis-tance algorithm is used to check the collision between anelement of the mesh and an object of the geometrical modelto calculate the mesh porosity (volume and area). Thecombustion model considers that the flame area increaseswith the intensity of the turbulence up to a maximum,after which reductions in the burning rate due to flamestretch decreases the flame area. The model has no de-pendence on the length scale of the turbulence. The onlylength scale is the laminar flamelet length scale which is adiffusive length scale associated with the internal structure

and with the maximum curvature of the laminar flamelet.The main concept is to quantify the length scale of theflame uniquely for the turbulent flame, assuming that theturbulent flame will select its own wrinkling length scalein accordance with the perturbations from the turbulentvelocity field ahead of the flame front. The modified Lax-Friedrichs scheme is applied in the finite volume formula-tion. The results of the simulation of initial phase of gasexplosion are in accordance with the current understandingof accidental explosions.

Tatiele FerreiraFaculty of Chemical Engineering - [email protected]

Rogerio SantosFaculty of Mechanical Engineering - University [email protected]

Savio ViannaFaculty of Chemical Engineering - University of [email protected]

CP3

An RCCE-ANN Tabulation Approach Applied toSydney Flame L

In this work, a tabulated mechanism for methane-aircombustion via Rate-Controlled Constrained Equilibrium(RCCE) and Artificial Neural Networks (ANNs) is pre-sented and applied to a highly extinguishing non-premixedturbulent flame from the Sydney burner. The objective ofour methodology is to train the ANN architecture on an ab-stract problem and then simulate a real flame of the samefuel, the Sydney flame L. In the present case, an ensem-ble of laminar flamelets with random strain rates is beingused to train the self-organized map (SOM) - MultilayerPerceptron (MLP) approach. In order to reduce the num-ber of variables and assist the ANN training, the RCCEapproach is applied on the GRI-1.2 detailed mechanism,reducing the chemical space dimensionality to 17 species.The flow field is resolved through Large Eddy Simulation(LES) method employing the Eulerian Stochastic Fieldsapproach as a solution scheme for the transport equation ofthe sub grid Probability Density Function (PDF) of the re-active scalars. Results demonstrate reasonable agreementwith experiments, whereas the SOM-MLP approach pro-vides a representation of the flame within reasonable CPUtimes, employing modest computation resources.

Lucas FrankeImperial College [email protected]

Stelios RigopoulosImperial College LondonDepartment of Mechanical [email protected]

CP3

Comparison of Differential Diffusion FlameletModeling Approaches in Turbulent Oxy-FuelFlames

Differential diffusion is an important phenomenon, espe-cially in oxy-fuel flames as experimentally shown by (Se-vault et al., Combust. Flame 159, 2012). However, theinteraction between turbulent and molecular diffusion is

36 NC17 Abstracts

not entirely understood now. Nevertheless, several mod-els exist to incorporate differential diffusion into turbulentflame modeling. Based on the data of the turbulent oxy-fuel flame investigated in (Sevault et al., Combust. Flame159, 2012), different diffusion modeling approaches in thecontext of flamelet modeling are investigated by means of aprior analysis and coupled LES. These models are: 1) equaldiffusivity of all species (Lei=1) (N. Peters, Proc. Com-bust. Inst. 21, 1986), 2) differential diffusion of species(mixture averaged diffusion) (H. Pitsch, N. Peters, Com-bust. Flame 114, 1998) and 3) incorporate influence of tur-bulent mixing by performing a blending between the previ-ous mentioned models (H. Wang, Phys. Fluids 28, 2016).As the results indicate, the pure models 1) and 2) are notable to reproduce the flame structure, whereas model 3)as a combination of 1) and 2) gives a much better agree-ment with experimental data. Nevertheless, discrepanciesare still observable in some species, which can not be over-come by introducing only one parameter which representsthe influence of turbulence. The importance of correct dif-fusion modeling is underlined by a coupled LES where erroraccumulation and propagation can be observed.

Sandro GierthTU Bergakademie [email protected]

Franziska Hunger, Sebastian PoppTU Bergakademie FreibergNumerical Thermo-Fluid [email protected],[email protected]

Matthias IhmeUniversity of MichiganMechanical [email protected]

Christian HasseTechnische Universitaet Bergakademie FreibergChair of Numerical Thermo-Fluid [email protected]

CP3

Portable Tabulation for Thermochemical and Ra-diation Properties in Combustion Simulations

Tabulation is common in combustion applications to re-duce computational time by performing expensive calcu-lations a priori and looking up tabulated results duringthe CFD simulation. We present two open-source librariesthat perform tabulation of thermochemical properties aswell as radiative properties. The thermochemical tabula-tion library (TabProps) supports one to five independentvariables and a variety of thermochemical models includ-ing flame sheet, equilibrium (adiabatic and with heat loss),steady laminar flamelets, etc. The radiative properly li-brary (RadProps) provides grey gas property calculationsfor reacting gas mixtures over a wide range of temperaturesand compositions. These libraries support various order ofinterpolants based on Lagrange polynomials. In addition,derivative calculations are also provided to enable Jaco-bian information to be obtained from the tabulated quan-tities. Both libraries support CPU and GPU calculations.We present performance results for these libraries, showingsignificant speedups on GPU of up to 120x over serial CPU

calculations for table retrieval.

Babak GoshayeshiUniversity of [email protected]

James C. SutherlandDepartment of Chemical EngineeringThe University of [email protected]

CP3

Spectral Matrix Analysis of the Semi-DiscreteFlamelet Equations

We use numerical eigensolvers to determine the spectra(sets of eigenvalues) of global discretization matrices repre-senting the transient flamelet equations. We perform thisanalysis to gain insight on the nature and time scales ofnonlinear coupling between diffusive transport and chem-ical kinetics. The flamelet equations allow precise controlof diffusive time scales through the scalar dissipation rate,facilitating studies of matrix spectra through transient ig-nition and extinction phenomena whose understanding iscrucial to the development of the advanced implicit meth-ods and nonlinear solvers necessary for detailed kineticmodels. Many methods stand to gain from this knowledge,such as operator splitting, spectral deferred correction, andadvanced continuation methods for traditional monolithicimplicit techniques.

Michael A. HansenUniversity of UtahSandia National [email protected]


CP3

Assessment of Flamelet Tabulation Strategies forPulverized Coal Combustion in a Strained FlowConfiguration

Pulverized coal combustion is a technologically relevantprocess in industrial furnaces. Modelling this process isdemanding due to multi-phase flow, heterogeneous reac-tions at particle surfaces and the structural complexity ofcoal in general. In this work, a flamelet modelling approach(FPV) is proposed that utilizes strained gaseous flamelets.As a reference case, a lean premixed methane-air stagna-tion flame with coal particle loading is investigated. Theoriginal setup has been proposed by Xia et al. [M. Xia,D. Zabrodiec, P. Scouflaire, B. Fiorina, N. Darabiha, Proc.Combust. Inst. (2016), in press], who also published ex-perimental data. Firstly, a full chemistry solution is val-idated against the experiments and thereafter the bound-ary conditions are varied to examine different extents ofchar burnout. The flamelet model is assessed with an a-priori analysis, where the full chemistry solution is usedfor a look-up from the flamelet table. Furthermore, calcu-lations with full coupling of the flamelet table (a-posteriorianalysis) are performed and examined. In the assessmentof the flamelet solutions, special attention is put on thecross-scalar dissipation rate, which can become importantwhen conditioning on multiple composition space variables

NC17 Abstracts 37

(mixture fractions and progress variables).

Arne ScholtissekTU Bergakademie FreibergTU Bergakademie [email protected]

Danny MessigTechnische Universitaet Bergakademie FreibergChair of Numerical Thermo-Fluid [email protected]

Michele VascellariVirtuhcon, Chair of Numerical Thermo-Fluid DynamicsTU [email protected]


CP4

DNS of An Autoigniting Air / N-Dodecane Tem-poral Jet at Diesel Engine Conditions

We present a direct numerical simulation of a turbulentautoigniting temporal jet between n-dodecane and dilutedair at conditions representative of low temperature dieselengine combustion. In this simulation, the initial temper-ature and pressure conditions were carefully selected to re-sult in a two-stage ignition event, in which low-temperaturereactions play an important role during the ignition pro-cess. Reaction rates were computed using a 35-species re-duced mechanism which included both the low- and high-temperature reactions pathways of n-dodecane. We focusour analysis on the mechanisms by which low-temperaturereactions assist high-temperature ignition. Preliminary re-sults indicate that ignition occurs at rich mixture compo-sitions and that, differently from what has been observedin previous DNS studies of single-stage autoignition, theignition delay time is shorter than the corresponding ho-mogeneous ignition delay time. Our study reveals that,during the first stage of ignition, several cool flames ap-pear within the lean regions of the jet and then quicklypropagate towards those flow regions with richer mixturecompositions, thus creating the conditions for hot ignitionto occur. We provide a detail description of the mechanismby which the cool flame propagates in physical space, aswell as of the flame propagation phase that follows local-ized autoignition.

Giulio BorghesiSandia National [email protected]

Jacqueline ChenCombustion Research FacilitySandia National [email protected]

Jacqueline ChenSandia National [email protected]

CP4

Eulerian Simulation of Polydisperse Two-PhaseFlame Propagation in a Turbulent Flow for a Large

Range of Stokes Numbers

In two-phase turbulent combustion, the description of thespray phase plays an essential role because of the evap-oration process that introduces a time lag for fuel avail-ability and also because the spray distribution may notbe homogeneous because of segregation effects induced bythe turbulence. To describe this spray phase, Eulerianmethods are here envisioned because of their great paral-lel efficiency and their ease of coupling with the gas phasecompared to Lagrangian techniques. These methods haveproven their capability to reproduce spray distribution inturbulent flows. In the present work, we propose to vali-date these moment methods in a reactive context, by in-vestigating the ignition of a turbulent cloud of droplets. Todescribe the polydispersity as well as the droplet trajectorycrossings inherent to turbulent flows, Two-Size Multifluid(TSM) moment method will be used in combination withthe Anisotropic Gaussian model. Simulations will be per-formed with the AsphoMUSES solver. By covering a widerange of Stokes numbers, this work will provide a validityrange for Eulerian methods for two-phase combustion.

Dennis Dunn, Macole Sabat, Jean Michel DupaysLaboratoire [email protected],[email protected],[email protected]

Jorge Cesar Brandle De [email protected]

Aymeric Vie, Frederique Laurent, Marc MassotLaboratoire [email protected], [email protected],[email protected]

CP4

Coupled Eulerian-Lagrangian LES-pdf Simulationof a Combustion System with Full Resolution ofthe Primary Atomisation

A combustion system operating at ambient condition, pre-viously studied experimentally by Rodrigues et al. [Com-bust. Flame 162 (2015), 759], is numerically simulated.The spray is injected through an industrial pressure swirlatomiser using liquid ethanol as fuel. The atomisation pro-cesses are simulated using a hybrid Eulerian-Lagrangianapproach in which the fluid interface is resolved usinga Volume-of-Fluid (VOF) method and liquid structureswhich become too small compared to the local mesh res-olution are converted into Lagrangian point particles thatare tracked based on the underlying flow. The evolution ofthe Lagrangian droplets in terms of evaporation and dis-persion follow the stochastic particle approach to includethe sub-grid-scale interactions. This allows for an accuratemodelling of the primary atomisation region while main-taining affordable computational cost, since the interfacedynamics of the small droplets are not resolved. The com-bustion simulation is performed in the context of LargeEddy Simulation (LES) and the transported pdf-equationfor the scalars is solved using the stochastic fields approach.The results show that the velocity profiles of the dropletswithin their size classes as well as the integral particle sizedistribution, which is represented by the Sauter Mean Di-ameter (SMD), measured in the corresponding experiments

38 NC17 Abstracts

are accurately reproduced. The gas phase temperature andvelocity are also in good agreement with the measurements.

Fabien Evrard, Simon Gallot-Lavallee, Fabian Denner,Berend van WachemImperial College [email protected],[email protected],[email protected], [email protected]

William JonesDepartment of Mechnical EngineeringImperial [email protected]

CP4

Numerical Investigation of the Stability of a SprayOxyfuel Flame Diluted by Carbon Dioxide

The influence of CO2 concentration on the characteristicsof spray flames is studied. It is common practice to adoptthis technique to comply with the regulations on NOx

production. A numerical investigation using Large EddySimulation where combustion is modelled using the pdfapproach with scalar field solved by the stochastic fieldsmethod is presented. In addition, the dispersed phase issimulated using the Lagrangian point particle approachand a conditional injection method is employed. A lab-scale experiment by Cleon et al. (2015) is selected to val-idate the results both for the dispersed and continuousphases. Three different CO2 dilution ratios are consid-ered. The comparison of the velocity fields and correlationof droplet size-velocity is promising for all cases. It is ob-served that the flame structures for the three cases revealsubstantial differences in the lift-off and reaction zones.Similar flame characteristics were also observed experimen-tally where an increased volume fraction of CO2 leads toa higher lift-off height and the presence of a double flamestructure. At a lower CO2 concentration, the flame is an-chored in the region close to the nozzle. CO produced bythe flame is also simulated and compared with the exper-imental data to understand the correlation with the flamecharacteristics. This work provides further insight in theanalysis of the flames considered together with a satisfac-tory agreement with the experimental results.

Simon Gallot-Lavallee, Dongwon Noh, Andrew MarquisImperial College [email protected],[email protected],[email protected]

William JonesDepartment of Mechnical EngineeringImperial [email protected]

CP4

Analysis and Regimes of Multicomponent SprayCombustion Using DNS

To examine the effect of multicomponent transportationfuels on the evaporation and combustion, direct numericalsimulations of a turbulent counterflow spray flame config-uration are performed under consideration of preferentialevaporation and combustion of a multicomponent surro-gate fuel. The simulation involves using accurate modelsfor multicomponent droplet evaporation and appropriatelyreduced mechanisms for the combustion in the gaseous

carrier phase. While previous work focused on the roleof preferential evaporation on the combustion in a ho-mogenous environment, this studies examines the role ofdroplet clusters and turbulent mixing on the evaporationand low-temperature ignition behavior. Results are com-pared against 0D batch-reactor simulations. Analysis isperformed to demarcate relevant combustion regimes formulticomponent spray-flames, introducing additional time-scales arising from the competition between preferentialevaporation, turbulence and reaction chemistry.

Pavan B. GovindarajuStanford [email protected]


CP4

Modeling N-Dodecane Spray Combustion with aRepresentative Interactive Linear Eddy Model

Many new combustion concepts are currently being inves-tigated to improve engines in terms of both efficiency andemissions. Examples include homogeneous charge com-pression ignition (HCCI), lean stratified premixed com-bustion, stratified charge compression ignition (SCCI), andhigh levels of exhaust gas recirculation (EGR) in diesel en-gines, known as low temperature combustion (LTC). Typ-ical combustion temperatures in all of these combustionconcepts have in common that the temperatures are lowerthan in traditional engines. To further improve and developcombustion concepts for clean and highly efficient engines,it is necessary to develop new computational tools that canbe used to describe and optimize processes in non-standardconditions, such as low temperature combustion. Thus, inthe presented study a recently developed model (RILEM:Representative Interactive Linear Eddy Model) for model-ing non-premixed combustion, regime-independently, wasused to simulate the so called Spray B, a heavy-duty opti-cal engine experiment that was performed within the En-gine Combustion Network (ECN) . The RILEM directlyresolves the influence of the mixing on the chemistry, orturbulence-chemistry interactions, through stochastic se-quences of statically independent eddy events. Cylinderpressure, heat release rates, ignition delay time and flamelift-off from the computation are compared to experimentsunder parametric variation of temperatures at differentoxygen contents.

Tim LackmannChalmers University of [email protected]

Tommaso Lucchini, Gianluca D’ErricoPolitecnico di [email protected], [email protected]

Alan [email protected]

Michael OevermannChalmers University of Technology

NC17 Abstracts 39

[email protected]

CP5

Linear Stability Analysis of Detonation Waves withRealistic Chemical Kinetic Schemes

The normal-mode, linear stability of the one-dimensional,Zeldovich-von-Neumann-Doring (ZND) detonation solu-tion yields information about the behaviour of multi-dimensional, detonation dynamics. The stability of detona-tion models has been explored in the last 20 years with in-creasingly more complex chemical kinetic schemes, thoughsuch schemes are still simple when compared to real chem-ical kinetics. We approach here the detonation stabilityproblem using realistic chemical kinetic schemes. The sta-bility problem is solved using a pseudo-spectral method.One hurdle, when solving this problem lies in finding asuitable, independent variable. So far, the problem hasmostly been expressed as a function of physical space orof a reaction progress variable, normally a mixture compo-nent mass fraction λi. In the first case, limitations arisefor simple, Arrhenius kinetic schemes, when the reactionzone is unbounded, while the second case is limited whenschemes with several reactions have all component massfractions with dλi/dx somewhere in the reaction zone. Wecircumvent this limitation by using particle velocity as anindependent velocity for kinetic schemes composed of onlystrictly exothermic steps and by considering entropy, thetrue reaction progress variable, for more complex schemes.Only ideal gas equations of state are considered so far.

Charles B. KiyandaConcordia University, Montreal, [email protected]

Mark ShortLos Alamos National [email protected]

CP5

The Role of Darrieus-Landau Instability on Turbu-lent Premixed Flame Propagation

The effects of Darrieus-Landau (DL) or hydrodynamic in-stability on flame propagation is investigated numericallyfor turbulent premixed flames in a Bunsen configuration.Recent experiments on air/propane Bunsen flames haveshown that by varying the equivalence ratio and/or theBunsen diameter the DL instability can be induced orsuppressed. Similarly, in numerical simulations, the in-stabilities are triggered by varying the ratio between theflame thickness and a representative hydrodynamic length,prompting a dramatic morphological effect on the flameand a relative increase in turbulent propagation speed.Simulations are carried out using a deficient reactant ap-proach in the low-Mach limit, implemented in the highlyscalable spectral element code nek5000. The deficient reac-tant model is coherent with results from asymptotic theorythus allowing stability limits to be known unambiguously.The spectral element method yields minimal numerical dif-fusion and dispersion, allowing a detailed characterizationof flame morphology and contributions to stretch. Thelatter is analyzed and statistically related to the flame cur-vature while the skewness of the curvature distribution isfound to be a consistent instability marker.

Pasquale Lapenna, Rachele LamioniUniversity of Rome La [email protected],

[email protected]

Francesco CretaUniversity of Rome, La SapienzaDepartment of Mechanics and [email protected]

Guido TroianiENEA C.R. [email protected]

CP5

Accuracy and Stability of Finite Differences in Pre-mixed Combustion DNS

Filtering is often used in high fidelity simulations ofcompressible reacting flows. The filtering is introducedto counter oscillations thought to be caused by under-resolution or numerical boundary schemes. This presen-tation outlines the role of flame induced heat release onthe stability of Direct Numerical Simulations. The effectsof heat release are examined via an imposed flame profile ina much simplified one-dimensional model problem, which isthen spatially discretized using commonly employed finitedifferences. Schemes that are Left Half Plane (LHP) stablefor non-reacting flows are found to lose this property in thepresence of temperature gradients; it is this loss of stabilitythat requires correction via filtering or damping throughdiffusive terms. The root cause of the destabilization istraced back to the discretization schemes capacity (or oth-erwise) to satisfy integration by parts. This observation, inconjunction with an application of the Lyapunov equation,then provides guidance for schemes which remain eitherabsolutely or conditionally stable with respect to heat re-lease. Examples are provided for one dimensional laminarflames.

Robert ProsserDept of Mechanical, Aerospace and CivilEngineering, University of [email protected]

CP5

Nonlinear Frequency Response Analysis of Lami-nar Premixed Flames

The stretched laminar flamelet model provides a conve-nient approach to embed local realistic chemical kineticswhen simulating turbulent premixed flames. The signif-icance of the transient aspects of strained flamelet mod-els has been discussed in the literature with assertionsthat their chemical time scales are sufficiently short com-pared to the turbulent time scales. Less discussed is theunsteady motion of a curved flame front component ofstretch rate. A model developed and validated for usewith transient premixed flame dynamics in a cylindrically-symmetric geometry was applied to study flame responsewhen the flow and scalar fields remain aligned (i.e., nostrain). The model is applied to conditions where theflame expands (positive stretch) and contracts (negativestretch) radially. This analysis suggests that laminar pre-mixed flames do not always approach the equilibrium un-stretched structure as rapidly as the flamelet model timescales imply, especially for lean premixed conditions. Theaddition of the externally-defined oscillating mass flow ratechanges the dynamics of the flame due to a changing stretchrate. Tracking such changes in the flame dynamics withfull chemistry requires considerable computational effort.Therefore, a frequency response analysis was applied as a

40 NC17 Abstracts

process characterization tool to study the flame dynamicsand unravel its complex non-linear processes using graph-ical and analytical tools (transfer functions).

Meysam SahafzadehRyerson [email protected]

Larry KostiukUniversity of AlbertaEdmonton, Alberta, [email protected]

Seth DworkinRyerson [email protected]

CP5

Flame Stabilisation and Dynamics in a SequentialCombustor at Atmospheric and High Pressure

The flame anchored in a sequential combustor fed by viti-ated air is investigated in this numerical study. The flamestabilization mechanisms and the flame response to tem-perature perturbations are studied at 1 and 10 bar usingLES with Analytically Reduced Chemistry. The simulateddomain is the second stage of a sequential combustor con-cept with methane injected into hot vitiated cross flow sup-plied from a first stage lean swirled flame.Results show that an increase of pressure P changesthe dominant stabilization mechanism from mainlypropagation-driven to pure autoignition. The transitionbetween the two is mapped over a wide range of unburnedgas temperature and P. Although both flames qualitativelylook similar they are subject to very different combustionprocesses.The flame response to inlet temperature modulation T ′ isalso investigated. It is shown that small T ′ induce largeamplitude heat release rate HRR response. This is be-cause, for most of the conditions investigated, the mainreaction zone is highly perturbed by autoignition kernelsdeveloping upstream in the mixing zone. In contrast toconventional swirled-turbulent flames, which often featurea monotonic decrease of the flame describing function gainwhen the acoustic perturbation amplitude is increased, theHRR response of the present flame can increase beyond acertain amplitude of T ′. This indicates that these flamescould be prone to triggering mechanisms due to inlet tem-perature perturbations.

Oliver SchulzCAPS LaboratoryDepartment of Mechanical and Process [email protected]

Nicolas NoirayCAPS LaboratoryDepartment of Mechanical and Process Engineering, [email protected]

CP5

Thermoacoustics of Annular Combustors

The aim of the present work is to predict the unsteady be-haviour of an 18-burner annular combustor in response toacoustic excitation. Computational Fluid Dynamics simu-lations using both URANS and LES modelling have beencarried out to capture the fully-coupled thermoacoustic in-

teractions in the chamber. Acoustic instabilities in leanpremixed annular combustors can cause high-amplitudepressure fluctuations. Resulting variations in the heat re-lease rate may also lead to self-sustained acoustic oscilla-tions. It is thus essential to be able to predict the effectof instabilities on a new combustor design. The work usesexperimental data from an 18-burner annular combustorrig built in the Cambridge University Engineering Depart-ment. Computer-aided Design work for a complete repre-sentation of the exact rig model has been completed. Ge-ometry repair has been undertaken and meshing has beenapplied for variants of the complex geometry from singleto 18-burner configurations. Initial single burner analysesconcerned with the choice of turbulence model have alsobeen performed. A reacting swirling flow study has beenconducted on the single burner model. Other single andmultiple-burner investigations are in progress which willinclude acoustically forced oscillating reacting flows, lead-ing up to LES of the full 18-burner configuration.

Audrey Valreau, Chin Yik Lee, Stewart CantUniversity of [email protected], [email protected], [email protected]

CP6

A Web-Based Tool for Simulation and NumericalAnalysis of Zero-Dimensional Combustion Prob-lems

Zero-dimensional reactors isolate chemistry from mixingand transport effects, enabling their usage in a variety ofapplications from chemical mechanism development andvalidation of basic combustion models for more complexflame simulation. These models isolate not only the chem-istry of combustion, but also the complex numerical diffi-culties of the chemistry. Analysis of the chemical sourceJacobian provides insight towards reduced mechanismsand improved numerical methods. This talk presents aweb-based application for simulation and analysis of zero-dimensional systems, which can generate transient and/orsteady state solutions for a wide range of mechanisms us-ing a very robust time integration scheme. The web-basedapplication also provides support for post-processing theresults to obtain transient eigenvalue and explosive modeanalysis. We briefly review the theory of the applicationas well as the time integration scheme and present resultsfor a variety of mechanisms.

Elizabeth Armstrong, Michael HansenUniversity of [email protected],[email protected]


CP6

The First Investigation of the Hamish Code: AnAdaptive Mesh Solver for Turbulent ReactingFlows

The Hamish code has been recently developed in the De-partment of Engineering, University of Cambridge to carryout direct numerical and large-eddy simulations of turbu-lent reacting flows. An unstructured adaptive mesh re-finement (AMR)-based finite-volume method is adoptedto resolve the fine flow structures presented in combustion

NC17 Abstracts 41

processes. The AMR data structure is built by the com-bination of the Morton code space filling method and theOctree algorithm, which allows the code to have a goodparallel performance. The Hamish code was respectivelyassessed for the Taylor-Green vortex (TGV) case using astatic mesh and a thermal diffusion problem using a dy-namically refined mesh. The assessments show that goodaccuracy is observed in computing the kinetic energy andresolving vorticity for the TGV case. The scalability of thecode is also assessed and a linear speedup is obtained upto 512 processors of a NextScale cluster for the TGV caseusing 1283 cells. In the thermal diffusion test case, a clearadvantage of using AMR is observed, compared to only astatic mesh. Fewer cells are needed and higher resolutionof the flame front is obtained when the mesh is dynamicallygenerated. The current version of Hamish will be furtheroptimised to improve its performance.

Jian Fang, Charles MoulinecDaresbury LaboratoryScience and Technology Facilities [email protected], [email protected]

David EmersonScientific Computing Department STFC [email protected]

Nilanjan ChakrabortyNewcastle [email protected]

Stewart CantUniversity of [email protected]

CP6

Numerical Simulation of Transcritical H2/O2Flame

Combustion in liquid rocket engines (LRE) happens un-der severe thermodynamical conditions: pressure exceedsthe critical pressure of injected propellants and temper-ature is cryogenic. Such a situation requires an impor-tant effort of modeling: real gas effects are incorporatedthrough cubic equations of state along with pressure-correction terms, and transport properties follow specificrules. Modeling for turbulent combustion is also an is-sue. To assess the validity of future turbulent combus-tion models, a two-dimensional direct numerical simula-tion is performed using the numerical solver SiTCom-B (https://www.coria-cfd.fr/index.php/SiTCom-B). Thisbenchmark corresponds to a splitter-plate configurationseparating a cryogenic flow of liquid oxygen from a gaseousflow of hydrogen. Both fluids experience a pressure level of10.0 MPa. Classical geometrical and incoming flow char-acteristics encountered in LRE are used. A detailed chem-istry containing 8 reacting species and 21 elementary re-actions is considered to model the oxy-combustion of hy-drogen. The impact of surface tension effects is assessedthrough a diffuse interface approach that is based on thesecond gradient theory.

Umut GuvenCORIA UMR CNRS [email protected]

Guillaume RibertCORIA - CNRS UMR6614

INSA de [email protected]

CP6

Numerical Methods for Transcritical Real-FluidReacting Flows Using the Flamelet Progress Vari-able Approach

A finite volume method with tabulated chemistry is devel-oped for simulating the turbulent reacting flows at tran-scritical conditions. Spurious pressure oscillations asso-ciated with fully conservative formulations are addressedby extending a double-flux model to real-fluid conditions.The flamelet progress variable (FPV) approach is extendedto be applied in consistence with the real-fluid equa-tion of state. An entropy-stable scheme that combineshigh-order non-dissipative and low-order dissipative finite-volume schemes is proposed to preserve the physical realiz-ability of numerical solutions across large density gradients.The resulting method is applied to a series of test cases todemonstrate the capability in simulations of problems thatare relevant for multi-species transcritical real-fluid react-ing flows.

Peter C. Ma, Yu LvStanford [email protected], [email protected]

Daniel BanutiStanford UniversityCenter for Turbulence [email protected]

Jean-Pierre HickeyUniversity of [email protected]


CP6

Identification of Low-Dimensional Manifolds inCoal Combustion

Previous studies have shown that PCA is an effectivemeans of identifying low dimensional manifolds within thethermochemical state space of turbulent combustion sys-tems, but to date, the application of PCA in the scopeof combustion has been limited to homogeneous gas-phasesystems. This talk applies PCA to coal combustion to iden-tify low-dimensional manifolds and generate models for thethermochemical state variables as functions of the principalcomponents. We demonstrate that low-dimensional mani-folds can be identified within the state space of a turbulentcoal combustion system for both gas and particle phasevariables using PCA. The results indicate that PCA canbe used to adequately parameterize gas and particle phasevariables when used in conjunction with a nonlinear regres-sion technique.

Josh T. McconnellUniversity of UtahDept. of Chemical [email protected]

James C. Sutherland

42 NC17 Abstracts

Department of Chemical EngineeringThe University of [email protected]

CP6

Transported PDF Modeling of Turbulent FlamesUsing the Flamelet Generated Manifold ChemistryModel

Numerical simulations of turbulent combustion using de-tailed reaction mechanism are computationally expensive.To reduce the computational cost, tabulated chemistrymethods such as the ?amelet generated manifold (FGM)method have been developed. In the FGM method thechemistry is reduced to the mixture fraction (a non-reacting scalar) and progress variable (a reacting scalar).For turbulent flames the FGM method is commonly com-bined with a presumed-shape PDF approach in which mix-ture fraction and progress variable are assumed to be in-dependent. In this work we will detail the methodology toaccount for turbulence-chemistry interaction by solving thecomposition probability density function (PDF) transportequation with a Lagrangian Monte Carlo method. Theproposed FGM/PDF method is implemented in the opensource CFD code OpenFOAM. We will investigate the ac-curacy of the FGM method by comparing predictions forSandia flames D & E based on a FGM table and based on adetailed chemical mechanism (DRM22) with available ex-perimental results. To enable a comparison, the FGM tableis based on non-premixed flamelet solutions using the sameDRM22 chemical mechanism.

Michael StoellingerUniversity of WyomingDepartment of [email protected]

Vasu JaganathUniversity of WyomingDepartment of MEchanical [email protected]

CP7

Modeling of Isolated Droplet Combustion of Soot-ing Fuels Under Microgravity Environment

Microgravity droplet combustion offers unique platformto study the sooting characteristics of single and multi-component real fuels. The spherically symmetric dropletburning configuration incorporates many important com-bustion aspects including moving boundary effect, de-tailed chemistry, soot formation and oxidation, radiativetransport and temperature dependent variable properties.In this numerical study, a recently developed 1-D multi-component droplet combustion model capable of incor-porating comprehensive kinetics and spectrally dependentradiation scheme has been utilized to analyze the soot-ing behavior of isolated droplets of ethanol (C2H5OH),n-heptane (n-C7H16) and primary reference fuel (PRF).A semi-detailed phenomenological soot model is incorpo-rated within the existing droplet combustion code. Modelpredictions of droplet regression history, flame stand-offratio (Df / Dd) and soot-shell stand-off ratio (Ds / Dd)are compared against the micro or reduced gravity dropletcombustion experimental results of ethanol, n-heptane andPRF blends available in the literature. Finally, the de-tailed flame structure of such sooting fuels are analyzedto comprehend the influence of soot on the overall droplet

combustion behavior.

Fahd E. AlamDepartment of Mechanical Engineering, University ofSouthCarolina, Columbia, [email protected]

Frederick L. DryerMechanical and Aerospace Engineering, PrincetonUniversity,Princeton, NJ, [email protected]

Tanvir I. FaroukMechanical Engineering, University of South Carolina,Columbia, SC, [email protected]

CP7

Droplet Formation and Recognition: A DropletTracking Algorithm for Primary Breakup Mod-elling

In this study, we conduct numerical simulations of sprayformation through air-blasted liquid-sheet breakup toinvestigate the formation and characteristics of liquiddroplets. The Robust Conservative Level Set (RCLS)method, coupled with high-order WENO treatment of thelevel-set transport equation, is used to capture the mo-tion and topological changes of the liquid-sheet, and theprimary breakup process. The need for droplet detectionand transfer arises from the computational modelling ofatomisation, which generally involves two stages: primarybreakup where drops are detaching from the liquid coreand secondary breakup where the droplets produced at theprevious stage further disintegrate into smaller droplets.The faithful prediction of the spray requires the simu-lation of both primary and secondary breakup. In thiswork, primary breakup is modelled intrinsically using theinterface-capturing method RCLS. The droplets generatedare then identified, removed from the level-set formula-tion, and stored for further analysis including the calcu-lation of geometrical and physical parameters. This strat-egy further allows the modelling capability to export thesedroplets as boundary conditions into a Lagrangian track-ing framework, equipped with an appropriate secondarybreakup model, to simulate the final fine spray formation,prior to spray combustion modelling.

Camille Bilger, Stewart CantUniversity of [email protected], [email protected]

CP7

Conjugate Heat Transfer Modeling in aKerosene/Air Spray Flame Impacting a Plate.Application to Fire Resistance on HelicopterCrankcases

Airworthiness standards require a fire resistance demon-stration for aircraft or helicopter engines to obtain a typecertificate. This demonstration relies on tests performedwith prototype engines in the late stages of the develop-ment. In these tests, a standardized flame with imposedtemperature and heat flux is placed next to the enginecasing during a given time. The aim of this work is toprovide a better characterization of a kerosene/air certifi-cation burner in order to reach a better understanding of

NC17 Abstracts 43

the thermal environment during fire tests. To this pur-pose, Large-Eddy Simulation of the certification burneris carried out. Spray combustion, forced convection onwalls, conduction in the solid parts of the burner and ra-diation of burnt gases are coupled to achieve a detaileddescription of heat transfer. Simulations are performed onunstructured grids with 40 million tetrahedral cells, us-ing the finite-volume YALES2 code. The spray is modeledwith a point-particle Lagrangian approach and the injec-tion parameters are obtained from dedicated experimentalmeasurements. The LES model is finally applied to theprediction of heat transfer in a flame impaction configura-tion. A well instrumented metal plate is here investigatedas a simplified test case. Experimental and numerical re-sults such as temperature and heat flux distributions arecompared and discussed. To a large extent, the aim is toprogress on fire test modelling so as to minimize the risksof test failure.

Lancelot BouletCNRS UMR 6614 - [email protected]

Pierre BenardCORIA - CNRS UMR6614, Universite et INSA de [email protected]

Ghislain LartigueCORIA - CNRS [email protected]

Vincent R. MoureauCORIA Laboratory - CNRS UMR6614Universite et INSA de [email protected]

Sheddia DidorallySafran Helicopter [email protected]

CP7

Counter-Flow Spray Pulsated Flames: From Ex-perimental Measurements to Numerical Simulation

The scope of the present contribution is to investigate aconfiguration of stationary and pulsated counterflow poly-disperse sprays flames, where the pulsation mechanismdoes not involve or excite any acoustic mode. First an orig-inal experimental set up is proposed fulfilling these speci-fications, as well as some new diagnostics and data anal-ysis tools in order to improve the time and space resolu-tion. This is especially important in order to propose a setof detailed quantitative comparisons with high-fidelity nu-merical simulations. These numerical simulations rely onboth a Lagrangian and Eulerian multi-fluid models able todescribe accurately polydisperse sprays in a multi-speciesreacting gaseous flow field modeled using the low Machnumber limit of the Navier-Stokes equations. We use anin-house code AsphoMUSES with realizable, robust andaccurate numerical methods in order to conduct direct nu-merical simulations of the proposed configurations, relyingon detailed boundary conditions provided by the experi-mental measurements. We present quantitative compar-isons between experimental measurements and simulationsand prove that the proposed Eulerian approach is able tocapture the two-way coupling of the gas-spray interactionsas well as combustion dynamics. Such a configuration isalso intended to become a reference set of solution in or-der to validate industrial code, as well as their models and

numerical methods for spray and gas resolution.

Jorge Cesar Brandle De MottaCoria, Universite de [email protected]

Dennis DunnEM2C, [email protected]

Matthieu BoileauIRMA, Universite [email protected]

Laurent Zimmer, Benjamin RobbesEM2C, [email protected],[email protected]

Eleonore Riber, Benedicte [email protected], [email protected]

Julien ReveillonCORIA, Universite de [email protected]

Frederique Laurent-NegreEM2C, [email protected]

Marc MassotLaboratoire [email protected]

CP7

A Filtered Tabulated Chemistry Model for LES ofSpray Combustion

The proposed study focuses on LES of two-phase reac-tive flows using tabulated chemistry. For that purpose,the Filtered TAbulated Chemistry for LES (F-TACLES)is applied for the first time in a spray combustion context.A look-up table is first generated using filtered flameletarchetypes. Then the ability of the methodology to cap-ture the propagation of 1-D filtered spray flames is ad-dressed for different conditions of spray injection such asvariation of droplet diameter and particle number density.The model is applied to the 3-D LES of a turbulent sprayflame. The retained experiment, measured at CORIA lab-oratory, France, is a bluff-body burner operated at atmo-spheric pressure where the n-heptane spray is injected asa hollow cone in a coflow of air. Comparisons between ex-perimental data and simulations for both reacting and non-reacting conditions are performed to assess the ability ofthe tabulated method and the LES flow solver to correctlypredict the dynamics of the gaseous and liquid phases, es-pecially the heat release rate distribution and the particles’position, velocity and temperature. The performances ofthe model to recover several key features of the turbulentflame, such as the lift-off height, are discussed.

Adrien ChatelierONERALaboratoire EM2C, CNRS, CentraleSupelec, [email protected]

44 NC17 Abstracts

Nasser DarabihaLaboratoire [email protected]

Nicolas [email protected]

Benoit FiorinaLaboratoire EM2C, Ecole Centrale [email protected]

CP7

Large-Eddy Simulation of Light-Round in an An-nular Combustor Equipped with N-Heptane SprayInjectors

A combined experimental and numerical study of light-round under perfectly premixed conditions has previouslydemonstrated the ability of large-eddy simulation (LES) topredict such ignition process in a complex geometry usingmassively parallel computations. The present investigationaims at targeting a configuration closer to real applicationsby considering liquid n-heptane injection. The large-eddysimulation of the ignition sequence of a laboratory scale an-nular combustion chamber comprising sixteen swirled two-phase injectors is carried out with i) a mono-disperse Eu-lerian approach for the description of the liquid phase andii) the thickened flame model with reduced chemistry forthe reactive gaseous phase. The objective is first to assessthis modeling approach to describe the two-phase reactiveflow during the light-round before considering more ad-vanced methods in the future. The simulation results arecompared in terms of flame topology and light-round dura-tion to the corresponding experimental high-speed imagesof the flame front propagation. Finally, analysis of thenumerical results enables to characterize the different phe-nomena involved in the flame propagation. Similarly topreviously investigated premixed conditions, the analysishighlights the influence of gas volumetric expansion on theabsolute turbulent burning velocity during the spray flamepropagation from burner to burner.

Thea LancienEM2C Laboratory, [email protected]

Kevin PrieurSAFRAN Tech, E&[email protected]

Daniel DuroxEM2C, CNRS, Ecole Centrale [email protected]

Sebastien CandelEM2C Laboratory, CNRS, [email protected]

Ronan VicquelinEM2C, CNRS, Ecole Centrale [email protected]

CP8

Scaling of Sooting Laminar Coflow Flames at Ele-

vated Pressures: A New Appraoch

Soot is formed as a result of combustion of a fossil fuelunder rich conditions or fuel pyrolysis. Laminar coflowdiffusion flames are often used to study soot formation atelevated pressures due to their well-characterized config-uration. Experimental studies of coflow laminar flamesare typically conducted at a constant mass flow rate (con-stant Reynolds number) at increasing pressures. A numer-ical simulation of coflow laminar sooting flame at pressuresranging from 1 to 8 atm was performed at constant massflow rate. The study clearly showed that, due to the effectof gravity, the flame shape changes as pressure is increasedand as a result, the mixing field changes, which in returnhas a great effect on soot formation. In this work, a novelscaling approach of the flame at different pressures is ex-plored. In this approach, both the Reynolds and Grashof’snumbers are kept constant so that the effect of gravity isthe same at all pressures. In order to keep the Grashofnumber constant, the diameter of the nozzle is modified aspressure varies. We report both numerical and experimen-tal data proving that this approach guarantees the samenon dimensional flow fields over a broad range of pres-sures. In the range of conditions studied, the Damkoehlernumber, which varies when both Reynolds and Grashof’snumbers are kept constant, is shown to play a minor role.Hence, a set of suitable flames for investigating soot for-mation at pressure is identified.

Ahmed AbdelgadirKing Abdullah University Of Science and Technology(KAUST)Clean Combustion Research Center (CCRC)[email protected]

Scott SteinmetzKing Abdullah University of Science and Technology(KAUST)Clean Combustion Research Center (CCRC)[email protected]

Antonio AttiliRWTH Aachen University, [email protected]

Fabrizio BisettiUniversity of Texas at Austin, [email protected]

William RobertsKing Abdullah University Of Science and Technology(KAUST)Clean Combustion Research Center (CCRC)[email protected]

CP8

Development of a Soot Particle Concentration Es-timation Library for Industrial Combustion Appli-cations

Soot emissions from combustion devices are known to haveharmful effects on the environment and human health. Asthe transportation industry continues to expand, the de-velopment of techniques to reduce soot emissions remainsa significant goal of researchers and industry. The complexgeometries of engines and gas turbines make it computa-tionally intractable to include detailed and accurate sootmodels in CFD simulations. This study leverages exist-ing knowledge in soot modelling and soot formation fun-

NC17 Abstracts 45

damentals to advance the development of a stand-alone,computationally inexpensive soot concentration estimatorto be linked to CFD simulations as a post-processor. Theestimator consists of a library generated using the La-grangian histories of soot-containing fluid parcels, whichcan then be used to predict soot concentration based ona pre-populated library. Updated results presented hereinindicate the estimator shows potential for predicting peaksoot volume fractions and soot emissions in laminar coflowdiffusion flames in atmospheric and high pressure condi-tions. Results also show that as more flame data is addedto the library to increase its accuracy, the predictive capa-bilities of the estimator become broader.

Raymond Alexander, Seth DworkinRyerson [email protected], [email protected]

CP8

Numerical Simulation of Soot Formation in Diffu-sion Flames

The world has a dependency on many different combustiondevices for a variety of applications to meet the needs ofmodern society. However, this dependency has a negativeeffect in that the use of these devices ultimately resultsin greenhouse gas emissions, thereby further polluting theEarth. For this reason, combustion research is critical togive insight on how to better design these systems to min-imize the harmful effects. Numerical simulation modellingof turbulent diffusion flames is still improving as it is notpurely analytic, but rather in a semi-empirical state cur-rently. This area of research involves the use of in-housecombustion CFD codes to provide detailed analyses. Thisallows for modifications to be made to the code in orderto test the results of proposed soot growth mechanisms.Through this methodology, numerical results can be com-pared to experimental data to determine whether or notthese proposed mechanisms have some validity. In recentliterature, results have shown that nascent soot can be richin aliphatics and that soot can undergo mass growth in theabsence of gas phase hydrogen atoms. For this reason, itis proposed that addition of aliphatic physical coagulationthrough collisions with soot may better characterize themass growth of soot.

Nemanja Ceranic, Seth DworkinRyerson [email protected], [email protected]

CP8

Comparison of Moments-Based Approaches forModeling Soot Population in Turbulent Flows

Representation of soot population is an important compo-nent in the computational prediction of particulate emis-sions. It is now accepted that moments-based approachesprovide the most cost-effective implementation. However,there are a number of moments-based, multi-variate tech-niques with different levels of numerical complexity. In thepast, development of such methods have been principallycarried out on canonical laminar and 0-D flows. However,their applications in realistic solvers developed for turbu-lent combustion may face challenges. In this work, the rela-tive computational expense of three common methods, CQ-MOM (Conditional Quadrature), HMOM (Hybrid), andECQMOM (Extended Conditional Quadrature), are testedin a canonical turbulent flame. The Sandia ethylene jetflame configuration is chosen as the baseline test case with

the KAUST high-pressure burner considered, using a simi-lar flow configuration but higher operating pressure. Largeeddy simulation (LES) is used as the turbulence modelingframework. In grid-filtered LES, the interaction of numeri-cal and modeling errors is a first-order problem, which canseriously undermine the accuracy of computational results.In the past, special moments-based methods for solversthat transport high frequency content fluid have been de-veloped. A similar analysis is carried out for the three sootmodeling approaches above. Specifically, realizability ofmoments methods with nonlinear advection schemes willbe discussed.

Shao Teng Chong, Venkat RamanUniversity of [email protected], [email protected]

Paul AriasUniversity of Michigan, Ann [email protected]

Hong ImKing Abdullah University of Science and [email protected]

CP8

A Multi-Variate Sectional Method for the Descrip-tion of Soot Production in Large Eddy Simulation

Soot control is an urgent societal issue and a politicaland industrial priority, due to its harmful impact on hu-mans and environment. Soot production is a complex phe-nomenon governed by collisional and chemical processesthat depend on the local properties of the gaseous phase,the flow and the particle size distribution (PSD). Theseprocesses lead to the emission of a population of solid par-ticles of different sizes and morphology, classically char-acterized by its PSD. As a consequence, in order to cor-rectly predict the total soot emission, a correct predictionof the evolution of the PSD is necessary. For this, sectionalmethods, based on a discretization of the PSD in differentsub-intervals of size, represent a promising alternative toobtain an accurate description of the PSD. Only recently,they have been recently applied to Large Eddy Simulationsof turbulent flames. In this work, a multi-variate extensionof the sectional method to account for the fractal nature ofsoot particles is proposed to improve its accuracy on thePSD prediction. Results from the mono-variate and multi-variate formulations are compared on laminar flames inorder to identify the best compromise between computa-tional cost and results accuracy. The impact of a mono- ormulti-variate description is finally evaluated by comparingresults on soot volume fraction in a Large Eddy Simulationof a turbulent flame.

Benedetta G. FranzelliEcole Centrale Paris, EM2C CNRS [email protected]

Aymeric Vie, Nasser DarabihaLaboratoire [email protected],[email protected]

CP8

Monte Carlo Simulation of Particle Formation in

46 NC17 Abstracts

Premixed Flames Using a Detailed Soot Model

A very detailed soot model has been developed by D’Annaand coworkers. It describes soot formation, growth, oxida-tion, fragmentation and dehydrogenation with a quadvari-ate population balance equation (PBE). Each entity of thepopulation is characterized by its type (large PAH, clusteror agglomerate), its state (stable or radical), its number ofcarbon atoms and its hydrogen/carbon ratio. The modelhas been applied in several studies using a sectional and amoment method (MOM). Another possibility to solve thePBE is given by Monte Carlo (MC) approaches. Due totheir high statistical accuracy, MC models serve as an ex-cellent reference tool for validation purposes. In MC, theparticle population is represented by a sufficiently large en-semble of stochastic particles whose size directly influencesthe computational effort. Thus, a standard MC implemen-tation is not advisable for very detailed models such asinvestigated here, as the number density of different typesof molecules, e.g. stable clusters vs. radical agglomer-ates, can differ by several orders of magnitude requiring ahuge number of stochastic particles. In this study, the sootmodel of D’Anna and coworkers is implemented in a novelMC framework. Using the concept of scaling, the numberof stochastic particles of each molecule type can be chosenindependently from the number density of the real systemto optimize the computational effort. Application of themodel is shown for a fuel-rich, laminar premixed flame.

Steffen SalenbauchNumerical Thermo-Fluid DynamicsTU Bergakademie [email protected]

Mariano Sirignano, Andrea D’Anna

Universit{a} degli Studi di Napoli Federico [email protected], [email protected]

Daniele Marchisio, Marco VanniPolitecnico di [email protected], [email protected]


CP9

Surrogate Models Based on the Combination ofPCA and Kriging

Engineering problems require the use of numerical simu-lations that require substantial computational resources.Combustion systems fall in this category. They are char-acterised by very complex physical interactions betweenchemistry, fluid dynamics and heat transport processes.Usually, a limited amount of resources is available. Thus,the development of reduced-order models is very appeal-ing, both for optimisation as well as for uncertainty quan-tification, to predict the state of a complex system in avery limited time. Ideally, those reduced models shouldpreserve the physics of the investigated phenomena, andbe developed from a limited number of expensive functionevaluations, i.e. CFD simulations. The combination ofPrincipal Component Analysys (PCA) with Kriging is con-sidered a promising approach in the attempt to solve thisproblem. Thanks to PCA, it is possible to enable the ex-traction of the invariant physics-related information of acombustion-related system and identify the system’s coef-

ficients which instead depend on the operating conditions.Kriging is then able to find a response surface for thesecoefficients. A surrogate model is built that is able to per-form parameter exploration with lower computational cost.The combination of the two techniques is the focus of thiswork. The methodology has already been applied to 1Dflames, with a number of input parameters ranging from 1to 3, and is now demonstrated on more complex systems,i.e. 2D and 3D simulations.

Gianmarco AversanoUniversite Libre de [email protected]

CP9

Improved Extrapolation-Based Stiff ODE Solversfor Combustion CFD

Increasingly large chemical mechanisms are needed to pre-dict autoignition, heat release and pollutant emissionsin computational fluid dynamics (CFD) simulations ofin-cylinder processes in compression-ignition engines andother applications. Calculation of chemical source termsusually dominates the computational effort, and severalstrategies have been proposed to reduce the high compu-tational cost associated with realistic chemistry in CFD.Central to most strategies is a stiff ordinary differentialequation (ODE) solver to compute the change in com-position due to chemical reactions over a computationaltime step. Most work to date on stiff ODE solvers forcomputational combustion has focused on backward dif-ferential formula (BDF) methods, and has not explicitlyconsidered the implications of how the stiff ODE solvercouples with the CFD algorithm. Recently, advantages ofextrapolation-based stiff ODE solvers have been demon-strated over BDF methods. In this work, improvements toextrapolation-based solvers with respect to accuracy andspeedup are discussed. Further potentials including hydrid(explicit/implicit) integration are demonstrated. Benefitsin CPU time and accuracy are shown for homogeneous sys-tems and compression-ignition engines, for chemical mech-anisms that range in size from fewer than 50 to more than7,000 species.

Abdurrahman ImrenThe Pennsylvania State [email protected]

Daniel C. HaworthPennsylvania State [email protected]

CP9

The Discontinous-Galerkin Method for ChemicalSource Term Integration in the Reacting Navier-Stokes Equations

A method for the accurate, fully implicit, integration ofchemical source terms for moderately large mechanismsis presented. Using a python library for symbolic math-ematics, Sympy, expressions of chemical source terms werere-written as pure analytical functions of species concen-trations, gas temperature, and thermodynamic constants.The source term functions were then differentiated with re-spect to fluid dynamic state variables using Sympy to ob-tain source term perturbations, source term adjoints, andsource term adjoint perturbations. The adjoint and pertur-bations were added to an existing Discontinuous-Galerkinspacetime finite element code, PROPEL, developed at the

NC17 Abstracts 47

Naval Research Laboratory. The chemical reactions wereintegrated in time using finite elements of polynomial orderone, two, and three to demonstrate high order capabilities.Results show that the chemistry can be integrated alongwith fluid dynamics at time steps on the order of 1e-3 s.Additionally, the mathematics outlined herein yield gridoptimization capabilities, such as adaptivity, and problemoptimization capabilities, such as pollutant minimizationand reaction sensitivity.

Ryan F. JohnsonNaval Research LaboratoryLaboratory of Computational Physics and [email protected]

Andrew Corrigan, Douglas Schwer, Andrew Kercher,Kazhikathra KailasanathNaval Research [email protected],[email protected], [email protected],[email protected]

CP9

Analysis of Operator Splitting Errors for Near-Limit Flame Simulations

High-fidelity simulations of the ignition, extinction andoscillatory combustion processes are of practical interest.Splitting schemes, widely employed in reactive flow sim-ulations, could fail for stiff reaction-diffusion systems ex-hibiting near-limit flame phenomena. The present workfirst employs a model perfectly stirred reactor (PSR) prob-lem with an Arrhenius reaction term and a linear mix-ing term to study the effects of splitting errors on near-limit combustion predictions. Analysis shows that the er-rors induced by decoupling of reaction and diffusion pro-cesses may result in unphysical extinction or ignition. TheStrang splitting, the balanced splitting, and a newly de-veloped midpoint method are tested with the prediction ofignition, extinction and oscillatory combustion in unsteadyPSRs of various fuel/air mixtures. Results show that themidpoint method can accurately reproduce the dynamicsof the near-limit flame phenomena and it is second-orderaccurate over a wide range of time steps. For the extinc-tion and ignition processes, both the balanced splitting andmidpoint method can yield accurate predictions, whereasthe Strang splitting can lead to significant shifts on the ig-nition/extinction processes or even unphysical results. Forthe sustainable and decaying oscillatory combustion fromcool flames, both the Strang splitting and the midpointmethod can successfully capture the dynamic behavior,whereas the balanced splitting scheme results in significanterrors.

Zhen Lu, Hua ZhouCenter for Combustion Energy, Tsinghua [email protected],[email protected]

Shan Li, Zhuyin RenCenter for Combustion Energy, Tsinghua UniversitySchool of Aerospace Engineering, Tsinghua [email protected],[email protected]

Tianfeng LuDepartment of Mechanical EngineeringUniversity of Connecticut

[email protected]

Chung K. LawDept. Mech. & Aerospace Engr.Princeton [email protected]

CP9

Efficient Numerical Algorithms Using AsymptoticEstimation of Mesh Parameter for Singularly Per-turbed Boundary Value Problems with and With-out Turning Point

Singular perturbations is a maturing mathematical sub-ject with a long history and continued important applica-tions throughout science and engineering. In this article wewould like to present an efficient numerical algorithm fora few classes of singularly perturbed boundary value prob-lems (SPPs) with and without turning point. It is wellknown that when classical methods on uniform meshes areused to solve SPPs, the result obtained are good only ifthe input size of the algorithm is very large. Therefore,the classical methods are not appropriate for practical ap-plications if the perturbation parameter is close to somecritical value. We would like to present our investigationin the direction of identifying a priori construction of non-uniform mesh based on asymptotic analysis of Shishkinmesh parameter to achieve better accuracy when comparedwith Shishkin mesh for singularly perturbed problems withand without turning point. The reduction to practice ofthe proposed algorithm is demonstrated through numeri-cal computations of various SPPs.

Ramesh VpAsst. Professor of MathematicsCentral University of Tamil Nadu, [email protected]

Prithvi M, Priyanga BResearch ScholarCentral University of Tamil [email protected], [email protected]

CP9

Encouraging Modern Software Development Prac-tices for Combustion

Modern combustion research, both computational and ex-perimental, relies on software and computational tools.However, due to a lack of saturation of modern software de-velopment practices, researchers often develop their tools ina manner that can take too long, lead to duplicated work,impede reproducibility, and lack verification. This talk willmotivate the use of tools and strategies that can save time,ensure trust in computed results, and encourage the adop-tion, further development, and reuse of research software incombustion and chemical kinetics. Techniques to be intro-duced include version control, software unit and functionaltesting, continuous integration, peer code review, repro-ducibility, benefits of releasing research software openly,and appropriate software citation. These topics will be ex-plored using mature combustion research software such asCantera and RMG, as well as newer packages like pyJacand PyKED, as examples.

Kyle E. NiemeyerOregon State [email protected]

48 NC17 Abstracts

Raymond L. [email protected]

Bryan W. WeberUniversity of [email protected]

Richard WestNortheastern [email protected]

CP10

Premixed Flame Propagation in a Boundary Layer

Methane-air premixed flames propagating in the vicinity ofa wall are simulated with complex chemistry and complextransport properties (mixture averaged), using a fourth-order fully compressible flow solver (SiTCom-B). 15 speciesand 26 reactions are involved in the chemical scheme, whichwas derived from the GRI-1.2 detailed mechanism, usingan automated reduction followed by an optimisation of therates with a Genetic Algorithm (ORCh method). The wallis either cooled at ambient temperature or heated by theflame, thus solving heat transfer in the solid part of themulti-physics simulations. The chemical structure of theedge-flame propagating near the wall is analysed along withthe deviation of the flow streamlines, which is found tocontrol the burning velocity of the propagating front. Inadditional simulations, the wall is heated by a source up-stream of the flame. Depending on the amount of heatadded to the system, upstream ignition or enhanced prop-agation of the initial flame through heat conduction areobserved. The controlling mechanisms are analysed in thelight of the response of chemistry to the added heat. Thecomplex interaction between the boundary layer and theheat transfer phenomena is further examined comparingthe numerical simulations with results from asymptotic de-velopments available in the literature.

Kevin BiocheCORIA CNRS & INSA ROUEN [email protected]

Guillaume RibertCORIA - CNRS UMR6614INSA de [email protected]

Luc VervischINSA Rouen CNRS [email protected]

CP10

Modeling Radiative Heat Transfer in Gas-Solid Re-acting Flows

Radiative heat transfer is an important heat transfer modein gas-solid reacting flows. Its importance increases re-cently because of stronger radiation in new combustiontechnologies, the demand of higher simulation accuracy,and improvements in modeling other processes. Model-ing radiative heat transfer requires a spectral model andan Radiative Transfer Equation (RTE) solver in a single-phase flow. The choice of the multiphase model furthercomplicates radiation models. For multiphase flows, an av-eraging model is usually required. Spectral models couldbe gray, nongray or a mix of gray and nongray for different

phases. Similar to the approach to the dispersed phases,RTE solvers can be Eulerian (e.g., P1 and Discrete Ordi-nate Methods) or Lagrangian (e.g., Photon Monte Carlo).Because they may be coupled with either an Eulerian orLagrangian multiphase model, this results in multiple pos-sible model combinations. A generic framework is helpfulin bridging the gap between intricate radiation modelingconcepts and diverse thermo-chemical environments in ap-plications. This was developed previously for gaseous com-bustion, and was found flexible, maintainable, usable andextensible. This research extends the previous frameworkfor gaseous combustion to gas-solid reacting flows. Exam-ples from Eulerian and Lagrangian dispersed phases arediscussed. Two levels of radiation model comparisons canbe made, and provide insights into model choices and newmodel developments.

Jian CaiUniversity of WyomingUniversity of [email protected]

CP10

Effect of Heat Transfer on Flame Stabilization andDynamics

Direct numerical simulations using complex chemistry ofV-flames stabilized behind cylindrical flame holders are in-vestigated in order to access the impact of heat transfer onthe flame response. Three different cases are considered:an adiabatic, an uncooled and a cooled cylinder. For thesecases, Flame Transfer Functions are computed and vali-dated against experimental results. The flame responsesfeature large differences for the three cases and are ex-plained by different flame root dynamics induced by theflame holder temperature. The results highlight the im-portance of heat transfer to walls for flame stabilizationand dynamics.

Abdulla Ghani, Daniel Mejia, Laurent Selle, ThierryPoinsotIMF [email protected], [email protected], [email protected],[email protected]

CP10

Heat Release Effects on Turbulence Statistics inPremixed and Nonpremixed Flames

Statistics of turbulent kinetic energy and scalars are ob-tained from a series of direct numerical simulations oflow Mach number spatially-evolving turbulent planar jetflames. In these simulations, hydrogen combustion is mod-eled using a detailed nine-species chemical kinetic mech-anism, and turbulent coflows ensure that high turbulenceintensity is maintained through the flame brush. Simula-tions are performed at the same moderate bulk Reynoldsnumber for both premixed and nonpremixed configurationsin addition to an analogous nonreacting configuration (coldflow). Budgets for the transport of turbulent kinetic en-ergy, scalar flux, and scalar variance are obtained condi-tioned on the progress variable for the premixed flame andon the mixture fraction for the nonpremixed flame and coldflow. These budgets are compared to one another to de-termine the role of combustion heat release in modifyingthe dominant terms in these budgets. Two key phenomenawill be the focus of the presentation. First, theoretical ar-guments have been made that the pressure-dilatation termin the turbulent kinetic energy equation is more important

NC17 Abstracts 49

in premixed flames than in nonpremixed flames, and theDNS data will be used to quantify any differences. Sec-ond, scalar flux and variance budgets will be compared forreacting and nonreacting scalars in order to determine thedirect role of the chemical source term.

Jonathan F. MacartDepartment of Mechanical and Aerospace EngineeringPrinceton [email protected]

Temistocle Grenga, Michael E. MuellerPrinceton [email protected], [email protected]

CP10

Radiative Heat Transfer Modelling in a Heavy-Duty Diesel Engine

Detailed radiation modelling in piston engines has receivedrelatively little attention to date. Recently, it is being re-visited in light of current trends towards higher operat-ing pressures and higher levels of exhaust-gas recirculation,both of which enhance molecular gas radiation. Advancedhigh-efficiency engines also are expected to function closerto the limits of stable operation, where even small pertur-bations to the energy balance can have a large influence onsystem behavior. Here several different spectral radiationproperty models and radiative transfer equation (RTE)solvers have been implemented in an OpenFOAM-basedengine CFD code, and simulations have been performed fora heavy-duty diesel engine. Differences in computed tem-perature fields, NO and soot levels, and wall heat transferrates are shown for different combinations of spectral mod-els and RTE solvers. The relative importance of moleculargas radiation versus soot radiation is examined. And theinfluence of turbulence-radiation interactions is determinedby comparing results obtained using local mean values ofcomposition and temperature to compute radiative emis-sion and absorption with those obtained using a particle-based transported probability density function method.

Chandan Paul, Arpan Sircar, SebastianFerreyro-Fernandez, Abdurrahman Imren, D. C. HaworthThe Pennsylvania State [email protected], [email protected], [email protected],[email protected], [email protected]

S. RoyMarquette [email protected]

W. Ge, M. F. ModestUC [email protected], [email protected]

CP10

Turbulence Radiation Coupling in Boundary Lay-ers of Heavy-Duty Diesel Engines

The lack of accurate submodels for in-cylinder radiationand heat transfer has been identified as a key shortcom-ing in developing truly predictive, physics-based computa-tional fluid dynamics (CFD) models that can be used todevelop combustion systems for advanced high-efficiency,low-emissions engines. Recent measurements of wall layersin engines show discrepancies of up to 100% with respectto standard CFD boundary-layer models. And recent anal-ysis of in-cylinder radiation based on the most recent spec-

tral property databases and high-fidelity radiative transferequation (RTE) solvers has shown that at operating pres-sures and exhaust-gas recirculation levels typical of modernheavy-duty compression-ignition engines, radiative emis-sion can be as high as 40% of the wall heat losses, thatmolecular gas radiation (mainly CO2 and H2O) can bemore important than soot radiation, and that a significantfraction of the emitted radiation can be reabsorbed beforereaching the walls. That is, radiation not only contributesto heat losses, but also changes the in-cylinder temperaturedistribution, which in turn affects combustion and emis-sions. The goal of this research is to develop models thatexplicitly account for the potentially strong coupling be-tween radiative and turbulent boundary layer heat transfer.For example, for optically thick conditions, a simple diffu-sion model might be formulated in terms of an absorption-coefficient-dependent turbulent Prandtl number.

Arpan Sircar, Chandan Paul, SebastianFerreyro-Fernandez, Abdurrahman ImrenThe Pennsylvania State [email protected], [email protected], [email protected],[email protected]

Daniel HaworthPenn State [email protected]

Somesh P. RoyDepartment of Mechanical EngineeringMarquette [email protected]

Wenjun Ge, Michael ModestUniversity of California [email protected], [email protected]

CP11

Large Eddy Simulation of Air-Flow Modulation onthe Dynamics of Two-Phase Swirling Flames forTwo Different Fuel Injection Technics

Staged multipoint injection has been proposed as a viableoption to control unstable phenomena in gas turbines leanpremixed prevaporized (LPP) combustors. Nonetheless,thermo-acoustic interactions that are prone to appear forsuch combustion regimes are still a major concern. TheBIMER combustor has been operated for several yearsto help understand and control the complex processes itsusage involves. The burner is composed of two swirlingstages: a pilot stage where fuel is injected through a pres-surized nozzle and a multipoint stage where fuel is injectedthrough ten equally spaced holes. In the present study,large eddy simulations of the BIMER combustor are carriedout with the two-phase flow (TPF) solver AVBP developedby CERFACS and IFPEN. The main objective is to eval-uate the impact of thermo-acoustic interactions throughtwo sets of simulations, pilot-only and multipoint-only in-jection, with and without the introduction of acoustic puls-ing. As in the experiments, in the pilot-only case, the flamestabilizes inside the injection system showing a typical V-shape. A strong precessing vortex core and low thermo-acoustic instabilities are observed. In the multipoint-onlyinjection, the flame is totally stabilized in an M-shape in-side the combustion chamber with an opposite dynamicalbehavior. The impact of the modulation of the bulk flow onthe flame shape and dynamics is carefully analysed, show-

50 NC17 Abstracts

ing very distinct features.

Leo Cunha Caldeira Mesquita, Artur Carvalho Santos,Benoit CheneauLaboratoire EM2C, CNRS, CentraleSupelecUniversite [email protected],[email protected],[email protected]

Aymeric VieLaboratoire [email protected]

Sebastien DucruixEM2C [email protected]

CP11

Large-Eddy Simulation of Pulverised-Coal Com-bustion

The ingredients required to perform Large-Eddy Simula-tion (LES) of pulverized-coal combustion with complexchemistry are discussed. The amount and the compositionof the volatiles released by a given coal vary with the heat-ing rate and the temperature applied to the coal particles.The asymptotic case of a high heating rate and high tem-perature is considered in line with pulverized-coal flamesstabilised by a pilot flame. In this context, numerical re-sults obtained with the devolatilization model by Maffeiet al. are compared against experiments in a drop tubefurnace and a flat flame burner. After estimating the pre-diction capabilities of this modelling for devolatilization, a19 species and 28 reactions chemical mechanisms is coupledwith the artificially thickened flame model to simulate theswirl-piloted pulverized coal burner studied by Balusamyet al. at Cambridge (UK). A point source Lagrangian ap-proach for the coal particles is coupled in two-way with alow Mach number Eulerian simulation of the carrying flow(YALES2 code), heat transfer by radiation is accounted forin the thermal budget of the coal particles. The mesh iscomposed of 108M cells with a resolution of the order of350 micro-meter. A systematic comparisons of the statis-tical results collected from LES are compared against theirexperimental counterpart.

Pascale DomingoCORIA - CNRS [email protected]

Dorian MidouCORIA CNRS & INSA ROUEN [email protected]


CP11

A Large Eddy Simulation of a Rotating DetonationEngine

Rotating detonation engines combust reactive gas mixtureswith a high-speed, annularly-propagating detonation wave,which provides many advantages over conventional com-bustors including a stagnation pressure gain and a more

compact, lightweight design. However, the non-premixednature of common fuel-air injection schemes can lead tosignificant flow-field inhomogeneities, which can affect thecharacter and stability of the rotating detonation wave.Therefore, this work seeks to glean insight into the prop-agation of the detonation wave using high-fidelity largeeddy simulation. A representative six-inch-diameter rotat-ing detonation engine is used for the geometry, and compar-isons are made to experimental data. From the simulation,we seek to quantify the effects of mixture stratification andturbulence on the operation of a rotating detonation engineand identify opportunities for design improvement.

Kevin [email protected]

Brent RankinAir Force Research [email protected]

John HokeInnovative Scientific Solutions [email protected]


CP11

Large Eddy Simulation and Probability DensityFunction Modelling of High-Speed Reacting Flows

Scramjet propulsion systems are regarded to be one of thekey technologies to deliver the next generation of hyper-sonic planes. In a scramjet engine combustion occurs atsupersonic speeds, this introduce limitations in the de-gree of mixing and increases the interactions between thechemistry and the flow. Numerical simulations of scram-jet combustion shed a light into the physics of supersoniccombustion. The present work aims to develop turbu-lent/combustion numerical models capable to reproducethe physics inside a scramjet. The work formulates anew joint scalar-velocity-energy probability density func-tion (PDF) equation in a Large Eddy Simulation frame-work. The formulation can deal with compressible reactiveflows at low and high Mach numbers. The model reducesthe number of unknown correlations in compressible tur-bulent flow from ten to four. The non-linear reactive termsare treated exactly. The Langevin model and the interac-tion by exchange with the mean micromixing models areconsidered to close the remaining unknown terms. In theproposed model, the PDF equation is solved using a Eu-lerian Stochastic Field. In contrast to Lagrangian-basedformulation, the model can be directly implemented in tra-ditional Eulerian-based CFD codes and shows no problemof pressure-velocity coupling. Validation of the model isperformed through the simulation of compressible reactingmixing layers. The results are then compared with existingDNS data from the literature.

Yuri Paixao de AlmeidaImperial College [email protected]

Salvador Navarro-MartinezDepartment of Mechanical EngineeringImperial College

NC17 Abstracts 51

[email protected]

CP11

Large Eddy Simulation of Reacting Flows at HighPressures Using GPU Acceleration

In high pressure combustors, the dispersion of fuel and thesubsequent combustion processes are significantly differ-ent from ambient conditions. Simulation of mixing andcombustion under such conditions requires a proper treat-ment of the thermochemical and molecular transport prop-erties including real fluid effects and supercritical phenom-ena. The combination of complex multi-component prop-erty evaluations along with the computational grid resolu-tion requirements makes these simulations expensive andcumbersome. Recent advances in high performance com-puting (HPC) systems, such as the graphics processing unit(GPU) based architectures provides an opportunity to re-duce the time to solution. Here, we present the accelerationof a software for large eddy simulation (LES) of turbulentcombustion. A combination of programming models hasbeen used to convert a distributed memory parallel code toa hybrid parallel code with multiple levels of parallelism.Compiler directives are used to add shared memory par-allelism for efficient use of multi-core processors. Majorperformance critical kernels have been re-implemented us-ing a generic programming approach in C++ that allowsefficient execution on GPU and other architectures, whileensuring performance portability. Simulation and perfor-mance results from the newest GPU accelerated and many-core systems are presented.

Ramanan Sankaran, Kalyana GottiparthiCenter for Computational SciencesOak Ridge National [email protected], [email protected]

Joseph C. OefeleinSandia National LaboratoriesCombustion Research [email protected]

CP12

Concept of Spectral Differentiation for Solving aFlow Model

The concept of differentiation with the first kind of spectralmethod is used in this presentation to solve the model ofmovement of flow around an upright angle. In this model,lots of flow features and interactions and separations takea place and hence a high accurate numerical techniques isneeded. Because of the singularities in some nodes, we useda conformal mapping which is used by many researchers. Anumerical simulation of the fluid movements will be showedalong side with some tables to validate our results withothers.

Badr AlkahtaniKing Saud [email protected]

CP12

Dissipation Element Analysis of Premixed SpatialEvolving Jet Flames

Dissipation element analysis is a tried and tested methodto analyze scalar fields in turbulent flows. Dissipation ele-ments are defined as an ensemble of grid point whose gradi-

ent trajectories reach the same extremal points. Therefore,the scalar field can be compartmentalized in monotonousspace filling regions. Dissipation elements can be statisti-cally described by two parameters, namely the Euclideandistance between their extremal points and their scalar dif-ference in these points. The joint probability density func-tion of these two parameters is expected to suffice for a sta-tistical reconstruction of the scalar field. In addition, nor-malized dissipation element statistics show an invariancetowards changes in Reynolds numbers. The dissipationelement analysis is applied to a set of spatial evolving pre-mixed jet flames at different Reynolds number. The simu-lations feature finite rate chemistry with 16 species and 73reactions and up to 22 Billion grid points. The jet consistsof a methane/air mixture with equivalence ratio φ = 0.7and temperature T=800K. The temperature and speciesconcentrations in the coflow correspond to the equilibriumstate of the burnt mixture. All the simulations are per-formed at 4 atm. Marginal and joint statistics of dissipa-tion element parameters are shown and compared to thoseof a DNS of a non-reacting spatial jet and isotropic tur-bulence. In addition, correlation between chemical speciesand dissipation elements is investigated.

Dominik DenkerRWTH Aachen UniversityInstitut fur Technische Verbrennung Aachen [email protected]


Stefano LucaKing Abdullah University of Science and [email protected]


Heinz PitschAachen [email protected]

CP12

A Variational Approach to Design a NumericalScheme on an Arbitrary Moving Grid for N-FluidFlow with Thermodynamic Consistency

In some highly demanding fluid dynamics simulations,ranging from chemical combustion to inertial confinementfusion, it appears necessary to simulate multi-fluid flowsinvolving numerous constraints at the same time, such as(and non-limitatively): large numbers of fluids (typically10 and above), both isentropic and strongly shocked com-pressible evolutions, large heat sources, large deformations,transport over large distances, and highly variable or con-trasted EOS stiffness. Fulfilling such a challenge in a robustand tractable way demands that thermodynamic consis-tency of the numerical scheme be carefully ensured. This isaddressed here over an arbitrarily evolving computationalgrid (Arbitrary Lagrange–Euler) by a three-step mimickingderivation: i) For compatible (approximately symplectic)exchange between internal and kinetic energies under isen-tropic conditions, a least action principle is used to gener-ate the proper pressure forces in the momentum equations;ii) For energy conservation, a tally is performed to matchthe internal and kinetic energies, and iii) For shock capture,

52 NC17 Abstracts

artificial dissipation is added (other physical terms couldalso be included such as drag, heat exchange, etc.). Variedsingle-, two- and multi-fluid test cases show satisfactory be-havior, including the 2D supersonic, high volume-fractionconvergence of eight Gaussian packets of different fluids ina background of perfect gas (under the sole pressure cou-pling).

Antoine [email protected]

Thibaud Vazquez-GonzalezCEA Bruyeres le [email protected]

Christophe [email protected]

CP12

On the Suitability of Deconvolution to Capture Fil-tered Premixed Flames Structure and Propagation

A possible modeling approach in LES of reactive flows isto deconvolve resolved scalars. By inverting the LES fil-ter, scalars such as mass fractions are reconstructed. Thisinformation can be used to close budget terms of filteredspecies balance equations, such as the filtered reaction rate.Being ill-posed in the mathematical sense, the problem isvery sensitive to any numerical perturbation. The objec-tive of the present study is to assess the ability of this kindof methodology to capture the chemical structure of pre-mixed flames. For that purpose, four deconvolution meth-ods are tested on a 1-D filtered laminar premixed flameconfiguration: the Approximated Deconvolution Method(ADM) based on Van Cittert iterative deconvolution, aTaylor decomposition-based method, the Regularized De-convolution Method (RDM) based on the minimizationof a quadratic criterion and finally a new method cou-pling ADM with a subgrid scale profile reconstruction usingparametric functions. Conducted tests analyze the abil-ity of the method to capture the chemical filtered flamestructure and front propagation speed. Results show thatthe deconvolution model should include information aboutsmall scales in order to regularize the filter inversion. Apriori and a posteriori tests showed that the filtered flamepropagation speed can then be well captured if the filtersize is not too large.

Cedric C. MehlEM2C laboratory, [email protected]

Jerome IdierIRCCyN [email protected]


CP12

Architecture-Aware Dynamic Repartitioning forTurbulent Reactors

Hybrid Eulerian-Lagrangian flow solvers are commonlyused for the simulation of turbulent reacting flows. Due

to turbulence-chemistry interactions these simulations aretypically very costly. Moreover, the evolving regions ofchemical reaction present unique challenges for designingefficient parallel solvers. The concepts of load balancing,(re)partitioning, and data migration become important de-sign considerations. We have developed PARAGON, anarchitecture-aware graph repartitioner, to address thesechallenges. PARAGON considers the performance im-pact of nonuniform network communication costs and con-tention on the memory subsystems of modern multicoreclusters. We compare the performance of this new tool toZoltan, developed at Sandia National Laboratories, whichprovides parallel partitioning, load balancing and data-management services. A scalability analysis and perfor-mance assessment is conducted for the case of a hybridEulerian-Lagrangian flow solver with reduced order, finite-rate kinetics as applied to a Taylor Green vortex flow withchemical reaction.

Peyman GiviUniversity of Pittsburgh, [email protected]

Patrick PisciuneriUniversity of [email protected]

CP12

Adaptive Numerical Solution of Advancing and Re-treating Edge Flames in a New Configuration

We study canonical edge flames to model extinction, reigni-tion, and flame lifting in turbulent non-premixed combus-tion. An adaptive-resolution finite-element method is usedto solve for laminar edge flames in the moving frame of ref-erence with respect to a spatially developing mixing layer.We solve the variable-density zero Mach number Navier-Stokes equations using a homotopy method. The propaga-tion speed of the edge flame is determined simultaneously(implicitly) with the scalar fields both for advancing andretreating flames. Pseudo arc-length continuation is usedfor parametric tracing of the propagation speed as a func-tion of reaction rate strength. Edge flame behavior as afunction of strain and Lewis numbers will be discussed.

Ben ShieldsUniversity of Illinois at [email protected]


Jonathan B. FreundUniversity of Illinois at [email protected]

CP13

Virtual Chemistry Applied to Pollutants EmissionPrediction

Chemical flame structures encountered in practical com-bustors are complex because multiple regimes coexist.Combustion modeling strategies based on single flamearchetype fail to predict pollutant species, especially CO.To account for mixed combustion regimes at a reducedcomputational cost a novel approach based on virtual op-timized mechanisms has been recently proposed. This

NC17 Abstracts 53

method consists in i) building a kinetic scheme from scratchinstead of reducing a detailed mechanism and ii) using vir-tual reactions and virtual species that do not representreal entities. In the present work, kinetic rate parame-ters and virtual species properties are optimized through agenetic algorithm to properly capture the flame/flow fieldinteraction and CO emissions for both premixed and non-premixed flame archetypes. The proposed virtual schemeis first evaluated on laminar flames showing a good agree-ment for the two targeted flame properties. Then a DNSsimulation of a 2-D laminar tribrachial flame is performedto challenge the developed virtual kinetic scheme on a con-figuration featuring different combustion regimes. The per-formances of the virtual model in terms of prediction andcomputational cost are compared against detailed chem-istry, analytically reduced chemistry and a global mecha-nism.

Melody CaillerLaboratoire EM2C CNRS, CentraleSupelecSafran [email protected]


Denis VeynanteLaboratoire EM2C CNRS, [email protected]


CP13

Adjoint-Based Sensitivity of Ignition in Non-Premixed Turbulent Flows

The uncertainty of ignition success in non-premixed turbu-lent flows remains a fundamental challenge in many practi-cal combustion systems. Mapping the spatial distributionof ignition probability often relies on trial-and-error test-ing, which becomes prohibitive when measuring sensitivityto a large number of parameters or varied flow conditions.An alternative approach is to formulate the adjoint of theperturbed and linearized governing equations in such a waythat sensitivity of ignition to an arbitrarily large numberof parameters can be obtained simultaneously via its solu-tion. Our previous studies have shown that it is possibleto obtain precision-limited sensitivity gradients for high-fidelity schemes which are attractive for simulating turbu-lent combustion. However, it remains unclear in generalhow well local sensitivity can describe nonlinear and un-steady processes. Moreover, adjoint methods are knownto suffer from cumulative error growth that results fromchaos, which is expected to be significant in turbulent com-bustion. In this study we perform direct simulations of anon-premixed turbulent shear layer and compute the cor-responding discrete-exact adjoint to obtain sensitivity ofignition to a set of design parameters. Different quantitiesof interest that quantify ignition success are considered,and the impact of this choice on sensitivity is addressed.The influence of flow realization and ignition source place-ment on sensitivity calculations is also reported.

Jesse CapecelatroUniversity of Michigan

[email protected]


CP13

Impact of Chemical Kinetic Model Reduction onPremixed Multi-Dimensional Flame Characteris-tics

The use of detailed chemical kinetic models for direct nu-merical simulations (DNS) is prohibitively expensive. Cur-rent best practice for the development of reduced modelsis to match homogeneous ignition delay times and lami-nar burning parameters such as flame speed and thicknessto predictions from the detailed chemical kinetic modelsusing zero- or one-dimensional calculations. Prior studiesusing reduced models implicitly assume that matching thehomogeneous and laminar properties of the detailed modelin a single-dimensional case will result in similar behaviorin multi-dimensional laminar and turbulent simulations.However, this assumption has not been tested. Fillo etal. recently demonstrated experimentally that real jet fu-els with similar chemistry and laminar burning parametersexhibit different sensitivities to multi-dimensional effectssuch as flame stretch. This result raises questions aboutthe validity of current best practices for the developmentof reduced chemical kinetic models for turbulent DNS. Thisstudy will investigate the validity of current best practices.Combustion parameters, including flame speed, thickness,and stretch rate, will be compared for three skeletal mod-els for the Princeton POSF 4658 surrogate model, reducedusing current best practice methods. DNS calculations ofpremixed, multi-dimensional flames will be compared todetermine if these methods are valid.

Aaron J. FilloOregon State UniversitySchool of Mechanical, Industrial, and Manufacturing [email protected]


CP13

Effect of Mechanism Reduction on the UncertaintyQuantification of Chemical Kinetics for MILDCombustion

In Moderate or Intense Low-oxygen Dilution (MILD) com-bustion the mixing time scale and the chemical time scaleare in the same order of magnitude. This implies thata detailed chemical mechanism should be used to accu-rately represent these conditions through computer simu-lations. However, existing detailed chemical mechanismshave been optimized and validated for conventional com-bustion, and the performance for MILD combustion is in-adequate. To improve the proficiency of chemical mecha-nisms during these conditions, Uncertainty Quantification(UQ) can be used to quantify and minimize uncertainties inthe chemical mechanism with respect to MILD combustiontargets. While the use of detailed chemical mechanisms isessential for MILD combustion, some species and reactionsmay not be relevant in these conditions. Mechanism reduc-tion schemes can therefore be applied in order to reducethe computational time, while still preserving accuracy ofthe simulations. Depending on which species and reactions

54 NC17 Abstracts

that are removed from the mechanism, there could be aneffect on the UQ process which should be considered. Cou-pling UQ with mechanism reduction for MILD combustionis therefore the focus of this work.

Magnus FurstUniversite Libre de [email protected]

Alessio FrassoldatiDepartment of Chemistry, Materials, and ChemicalEngineeringPolitecnico di [email protected]

Alessandro ParenteUniversite Libre de [email protected]

CP13

A Reduced Chemical Mechanism for Kerosene viaan RCCE-CSP Methodology

A detailed mechanism for the oxidation of kerosene maycontain hundreds of species and thousands of reactions,postulating the use of reduced chemical mechanisms. Rate-Controlled Constrained Equilibrium (RCCE) is a system-atic method for the reduction of mechanisms, according towhich the slow species are evaluated from the chemical ki-netics of the detailed mechanism, while the fast speciesare assumed to be in an equilibrium state that is con-strained by the slow species, through a minimisation ofan energy function. The selection of these species relieson the separation of time-scales, which is here investi-gated with Computational Singular Perturbation (CSP).The reduced mechanism is derived from one-dimensionalnon-premixed flamelets with varying strain rate, and con-sists of 42 species out of 369 species in the detailed mech-anism with a surrogate fuel based on n-dodecane. Subse-quently, the mechanism is not only tested successfully innon-premixed flamelets, but also in one-dimensional pre-mixed flames, perfectly stirred reactors and in flameletswith time-dependent strain rate to evaluate the dynamicsof the reduced mechanism. An overall very good agreementis obtained in all problems, indicating that the mechanismcan be employed in a wide range of combustion regimes,not restricted to the ones employed for its derivation.

Panayiotis Koniavitis, W. P. JonesImperial College [email protected], [email protected]

Stelios RigopoulosImperial College LondonDepartment of Mechanical [email protected]

CP13

Rapid Reduction of a Chemical Kinetic Model forthe Combustion of the Pyrolysis Oil SurrogateEthylene Glycol

This work focusses on the reduction of a chemical kineticmechanism based on a novel linear transformation modelwhich is numerically inexpensive. As an example, themethod is applied to a newly developed detailed chemi-cal kinetic model for the combustion of ethylene glycol—asubstance being used as a surrogate for pyrolysis oil. In thefirst step of the rapid reduction, this model is reduced for

atmospheric combustion conditions in air. Thereby, the ex-tent of the chemical kinetic model is significantly reducedfrom 85 to 29 species, including the inert species N2 andAr, and reduced from 643 to 132 reactions. In the secondstep of the rapid reduction, the reduced model is subse-quently optimized with target data, species profiles fromhomogeneous combustion and laminar flame speeds, whichare created numerically with the detailed model. With thissubsequent optimization the reduced model is capable tonumerically recreate this target data with high accuracyfor a wide range of conditions. The numerical effort of thiscomplete reduction procedure is low and the procedure ishighly automatable. The computational time of this pro-cedure takes around half an hour on 32 state of the artCPUs.

Torsten MethlingGerman Aerospace Center (DLR)Institute of Combustion [email protected]

Trupti KathrotiaGerman Aerospace Center (DLR), Institute [email protected]

Uwe RiedelGerman Aerospace [email protected]

CP14

LES Investigation of Fuel Effects on Lean Blow off(LBO) for a Realistic Two-Phase Flow Combustor

The development of gas turbines that operate at lean con-ditions is needed to meet increasingly stringent emissionregulations. By operating at lean conditions lower tem-peratures are observed in the combustor chamber and areduction of NOx emissions is achieved. However, in leanconditions these gas turbines are susceptible to blowoutas the flame stabilization mechanisms are weakened. Inthe present work, the lean blow-out (LBO) limit is in-vestigated in order to observe the combustion dynam-ics near blowout and determine optimal operating condi-tions. This is accomplished using large-eddy simulationsof a realistic two-phase flow combustor operating near theLBO limit. Liquid spray is modelled using a polydis-perse droplet injection with stochastic modeling of dropletbreakup and a Lagrangian spray evaporation model. Theflow field and gas phase chemistry is solved using an un-structured Navier-Stokes solver for complex geometries anda flamelet/progress variable formulation, respectively. Theeffect of fuel composition is investigated to determine itsimpact on the LBO limit and the transition from stableoperating conditions to blowoff.

Jeffrey Labahn, Lucas EsclapezStanford [email protected], [email protected]


CP14

Large Eddy Simulation of Non-Conventional Com-

NC17 Abstracts 55

bustion Regimes

During the past few decades, a number of innovative com-bustion technologies has been proposed. One of the mostpromising technologies, Moderate or Intense Low-oxygenDilution (MILD) combustion, features very low NOx andCO emission, while ensuring very high efficiency. Thepresent work focuses on the validation of numerical simu-lation of turbulent combustion under MILD conditions, inthe Adelaide Jet-in-Hot-Coflow (JHC) burner. The Ade-laide JHC burner has a central jet with methane and hy-drogen on the molar basis of 50/50. A hot co-flow withdiluted oxygen is provided in the annulus region to ignitethe central jet fuel. Experimental data of species mass frac-tion and temperature are available for comparison. Clo-sures based on the Perfectly Stirred Reactor (PSR) andPartially Stirred Reactor (PaSR) concepts are selected assub-grid models for the finite rate chemistry. The pim-ple algorithm is implemented in the transient solver. Stiffchemistry is handled with the OpenSMOKE library. Cur-rently, the RANS simulation of the JHC burner has beenconducted showing the sensitivity of the results to differentmodeling parameters and numerical approaches. Based onthe results, Large Eddy Simulation are being performedwith global chemistry, to adjust the inflow boundary con-ditions. Then, LES of the JHC case will be extended toinclude detailed chemistry.

Zhiyi LiAero-Thermo-Mechanics DepartmentUniversite libre de [email protected]

Alberto CuociDepartment of Chemistry, Materials, and ChemicalEngineeringPolitecnico di [email protected]

Amsini SadikiDepartment of Energy and Power Plant Technology,[email protected]


CP14

Large Eddy Simulation of Lifted Turbulent FlameUsing Doubly Conditional Source-Term Estimation

Lifted turbulent flames are found when the fuel injec-tion or coflow velocity is too high for stabilization at theburner rim. In atmospheric cold air, without autoignition,these flames stabilize in a partially-premixed combustionmode. The present study is focused on simulating a se-ries of lifted turbulent jet flames stabilized in cold air atdifferent Reynolds numbers using Large Eddy Simulation(LES) coupled with Doubly Conditional Source-term Esti-mation (DCSE) to reproduce the partially-premixed flamestabilization mechanism. Detailed chemistry is incorpo-rated using Trajectory-Generated Low Dimensional Man-ifolds (TGLDM). The objectives of the present work areto implement a reliable LES-DCSE methodology to simu-late lifted turbulent flames and assess the current modelsto predict the lift-off height. As a first step, one Reynoldsnumber will be considered. The numerical predictions thatwill be presented include methane concentrations at differ-

ent locations throughout the flame and the lift-off height.The numerical results will be compared with previous val-ues obtained by Reynolds-Averaged Navier Stokes (RANS)calculations and available experimental data.

Mohammad Mortada, Cecile B. DevaudUniversity of WaterlooMechanical and Mechatronics [email protected], [email protected]

CP14

LES of Core Noise in a Combustor Nozzle System

As the noise generated by other acoustic sources is reduced,combustion or core noise has emerged as a growing concernfor aero-engine designers. This work centers on numericalsimulation of an experiment of a dual-swirl methane-aircombustion chamber with the exhaust passing through atransonic converging-diverging nozzle performed at DLRBerlin (Bake et al., 2009). Large Eddy Simulation (LES)is used to predict the in-chamber and downstream acous-tics, and these pressure spectra, as well as velocity andflame structure predictions, are validated against DLR’sexperimental results. Modal decomposition is applied tothe fields inside the combustion chamber to provide addi-tional insight into the dynamics leading to sound produc-tion. The focus of the downstream portion of the domainis on probing the sensitivities of indirect noise mechanisms,including the recently discovered composition noise mech-anism (Ihme, 2017; Magri et al., 2016) which predicts thatfluctuations in mixture fraction can give rise to indirectnoise. This work represents the first three dimensional,high-fidelity evidence of the low order composition noisetheory. Other aspects of indirect noise generation, includ-ing sensitivity to non-planar waves and fluctuation spatialstructure, are examined in detail as well. All results, in-cluding composition effects, are compared against existinglow order theory.

Jeffrey D. O’BrienStanford University - Center for Turbulence [email protected]

Friedrich BakeGerman Aerospace [email protected]

Yu LvStanford [email protected]


CP14

Large Eddy Simulation of Co2 Dilution in Pre-mixed Swirling Oxy-Flames and Assessment of Ra-diation Effects

The very high temperature of burnt products in oxy-combustion burners is usually tempered with the recircu-lation of exhaust gases, such as CO2. The effect of thisdilution on the flame stabilization has been investigatedexperimentally in comparison to conventional methane-airflames. Two configurations (CH4/air and CH4/O2/CO2

flames) have been retained for the present numerical study.The challenge is to retrieve both flames behavior with the

56 NC17 Abstracts

same modeling approach. The validation is carried out bycomparing with experimental fields of velocity, OH∗ chemi-luminescence and burnt gases probability distribution de-duced from OH-PLIF. For both configurations, large-eddysimulations (LES) are performed with the F-TACLES (Fil-tered Tabulated Chemistry for LES) combustion modelwhich is based on tabulated chemistry to account for com-plex chemistry at low computational cost in premixedflames. After an initial simulation under adiabatic wallconditions, wall heat losses are accounted for by i) impos-ing the measured wall temperature in the LES and ii) ac-counting for the enthalpy defect in the tabulated chemistrymodel. Finally, given the high concentration of CO2, radi-ation effects are very likely to be significant. To accountfor radiation emission and absorption in the burnt gases, areciprocal Monte-Carlo method is used to accurately assessthe importance of radiation in the different configurations.

Lorella PalluottoEM2C [email protected]


Paul Jourdaine, Clement Mirat, Thierry SchullerEM2C [email protected], [email protected],[email protected]

Olivier GicquelEM2C LaboratoryEcole Centrale [email protected]

CP14

LES-FDF with Hybrid Finite Rate and FlameletChemistry Modeling of a Piloted Turbulent Flamewith Inhomogeneous Inlets

A hybrid large eddy simulation (LES) method combin-ing flamelet tabulation with transported filtered densityfunction (FDF) finite rate chemistry strategies has beendeveloped and applied to simulate the Sydney/Sandia pi-loted turbulent flame with inhomogeneous inlets [Meares &Masri, 2014; Barlow et al., 2015]. The flame is reported toexhibit stratified-premixed as well as diffusion-dominatedmodes, which renders classical combustion models that ei-ther work for premixed or non-premixed flames intractableto accurately predict this flame. The method presentedcombines the combustion regime independent transportedFDF method with a computationally cheap flamelet-basedmethod in a hybrid manner. The computationally expen-sive Lagrangian particles representing the transport of theFDF are seeded only in certain locations whereas the restof the domain is treated with flamelet chemistry based onthe LES transported fields and an appropriate presumedPDF closure. The method relies on consistency betweenEulerian and Lagrangian fields through robust coupling.Seeding of the particles is based on LES transported mix-ture fraction, its variance and a progress variable. Theperformance of the hybrid model is verified by an exten-sive comparison to the experiment including mean and rmsprofiles of species, conditional averages and scatter plots.It is also shown that the method can efficiently be used forflames exhibiting local extinction and finite rate chemistry

effects.

Martin RiethUniversity of [email protected]

Suresh MenonGeorgia Inst. of TechnologySch.of Aerospace [email protected]

Fabian ProchChair of Fluid DynamicsUniversity of [email protected]

Andreas KempfDuisburg-Essen [email protected]

CP15

Dynamic Mode Decomposition of Turbulent Non-Reacting and Reacting Nonpremixed Jets

Dynamic Mode Decomposition (DMD) decomposes datainto coherent modes with corresponding growth rates andoscillatory frequencies, allowing for the investigation of un-steady and dynamic phenomena unlike conventional statis-tical analyses. The method identifies structures unbiasedby energy so is particularly well suited to exploring dy-namic processes at scales smaller than the largest, energy-containing scales of the flow. In this work, DMD is usedas a tool to analyze a series of large three-dimensional Di-rect Numerical Simulations of low Mach number spatially-evolving turbulent planar nonpremixed hydrogen/air jetsboth reacting and non-reacting. The focus of this investi-gation will be on the physical insights that may be derivedfrom the DMD modes and changes in the modes associatedwith combustion heat release.

Temistocle GrengaPrinceton [email protected]

Jonathan F. MacartDepartment of Mechanical and Aerospace EngineeringPrinceton [email protected]

Michael E. MuellerPrinceton [email protected]

CP15

Nox Formation in Turbulent Premixed Slot Flameswith Mixture Inhomogeneity: A Numerical Study

A set of Direct Numerical Simulations of three-dimensionalmethane/air lean flames in a spatially developing turbu-lent slot burner are performed. The flames are in thethin-reaction zone regimes and the jet Reynolds number is5600. This configuration is of interest since it displays tur-bulent production by mean shear as in real devices. Thegas phase hydrodynamics are modeled with the reactive,unsteady Navier-Stokes equations in the low Mach num-ber limit. Combustion is treated with finite-rate chemistry.The jet slot width is H=1.2 mm and the computational do-main is 24Hx16Hx4H discretized with 1440x920x256 points

NC17 Abstracts 57

for a total of 350 Million cells. The jet is characterized bya non-uniform equivalence ratio at the inlet and varyinglevels of incomplete premixing for the methane/air mix-ture are considered. The global equivalence ratio is 0.7and temperature is 800 K. All simulations are performedat 4 atm. The instantaneous profiles of the mass fractionsof methane and air at the inlet are sampled from a set ofturbulent channel simulations that provide realistic, fullyturbulent fields. The data are analyzed to study the influ-ence of partial premixing on the flame structure. Particularfocus is devoted to the assessment of heat release rate fluc-tuations and NOx formation. In particular, the effects ofpartial premixing on the production rates for the variouspathways to NOx formation are investigated.




CP15

Generalized Turbulent Combustion Model forMulti-Modal Combustion

Roughly speaking, turbulent combustion models can be di-vided into two broad classes: models that make no assump-tion about the underlying combustion processes and mod-els that constrain the underlying combustion processes tosome a priori presumed low-dimensional manifold. The for-mer class of models, including Transported PDF (TPDF)and Linear Eddy Model (LEM), is by nature more generalbut comes at increased computational cost. The latter classof models, including ’flamelet’ and ’flamelet’-like modelssuch as Conditional Moment Closure (CMC), is computa-tionally more efficient albeit with the need to assume some-thing a priori. In this work, a new turbulent combustionmodel for LES is presented that breaks this trade-off, es-sentially a generalization of ’flamelet’ models that requiresno a priori assumption about the underlying combustionprocesses. The model is constructed by first assuming thatall (adiabatic, isobaric, two-stream) combustion processescan be described on two-dimensional manifold consistingof a mixture fraction and a generalized progress variableon the unity square. A transformation of the governingequations is performed into these coordinates to describethe evolution of the manifold, and this also provides an ex-plicit definition for the generalized progress variable. Thistwo-dimensional space is shown to recover the three asymp-totic modes of combustion under certain limits. Extensionsof the model to consider additional physics will also be dis-cussed.


CP15

Turbulent Flame Sub-Grid Scale Modeling withHigh-Order Spectral Difference

A novel approach to Large-Eddy Simulation (LES) of tur-bulent combustion is discussed in the context of high-order

Spectral Difference (SD). In these numerical methods, thescalar signals and their corresponding fluxes are approx-imated through polynomial expansions. It is proposedto extend this polynomial decomposition to the chemicalsources of chemical species. A sensor constructed fromthe modal decay rate of the polynomial approximation ofthe chemical source allows for automatically locating flowzones where the mesh resolution is too coarse for the flamesignal (i.e. source terms) to be resolved. This sensor iseasily related to a thickening factor in order to calibrate,from a direct treatment of the scalar signal seen in thesimulation, an artificially thickened flame closure. A sim-ilar treatment is applied to the components of the scalargradients, to calibrate the sub-grid scale flame wrinklingfactor from the energy of the modes of the resolved scalargradient. The method is first applied to one-dimensionalflames at various mesh resolutions and orders of discretisa-tion. In a second part, a three-dimensional reactive mixinglayer is simulated. Starting at a high level of resolution, themesh is made coarser and statistical results of the varioussimulations are compared.


Eurielle Bossennec, Guido LodatoCORIA CNRS & INSA ROUEN [email protected], [email protected]

CP15

Large Eddy Simulation of a Turbulent SwirlingPremixed Flame Coupling the TFLES Model witha Dynamic Wrinkling Formulation

Dynamic models that take advantage of the known resolvedscales to automatically adjust the model parameters haveproved to be very effective in large eddy simulations (LES).Global (uniform parameter evolving only with time) andlocal (parameter evolving both in space and time) dynamicformulations for the flame wrinkling factor are combinedwith the Thickened Flame (TFLES) model and simula-tions of the semi-industrial PRECCINSTA burner studiedexperimentally by Meier et al. (2007) are performed for thestable and unstable configurations. For the stable flame,dynamic and non-dynamic approaches capture flow andcombustion statistics, both in terms of Favre and quasi-Reynolds averages, with good accuracy. Interestingly, theself-excited mode is reproduced only when the dynamic for-malism is employed. A mesh convergence proves that theobserved instability is not the result of a numerical artifactand a different mechanism other than the hypothesis of im-perfect mixing, as suggested by Franzelli et al. (2012), caninfluence the flame pulsation. Dynamic models may thenplay an important role in the prediction of combustion in-stabilities.

Pedro S. VolpianiLaboratoire EM2CCNRS, CentraleSupelec, Universite [email protected]

Thomas SchmittEM2C, CNRS, Ecole Centrale [email protected]

Denis VeynanteEM2C LaboratoryEcole Centrale Paris

58 NC17 Abstracts

[email protected]

CP15

Transitional Behavior in the Regime from LiftedFlames to Mild Flames

Turbulent lifted flames in hot and diluted environmentsattracted numerous study since its wide application. Au-toignition was proven a key factor in stabilizing theseflames1. When lowering coflow temperature and oxy-gen ratio towards MILD conditions, namely a transitionalflame is found with an extending distribution of CH2Oto jet exit and OH transition from weak to strong atliftoff height, suggesting enhanced preignition2. The cur-rent study uses LES/FPV approach to simulate behaviorand structure of transitional flame. Two coflow conditionsat different temperatures with same composition are con-sidered, corresponding with lifted flames and transitionalones. Temporal-spatial-resolved ignition processes are re-vealed in both cases. Faint triple flame structure is foundat flame base, indicates partial premixing stabilizing bothflames, however denser CH2O distribution shown in thetransitional flame indicates stronger partial premixing. Amoderate reaction zone in lifted region suggests potentialexistence of MILD regime at the very transition state. Sta-tistical results confirm difference of CH2O distribution be-tween cases, besides, conditional statistics on mixture frac-tion showed diverse reaction paths of CH2O under theseconditions.

Chengyu Liu, Jian ZhangInstitute of Mechanics, Chinese Academy of [email protected], [email protected]

Yanhong MaSchool of Energy and Power EngineeringBeihang [email protected]

CP16

Bayesian Analysis of Constrained Equilibrium Re-duced Kinetics Model Parameterization

Bayesian inference is used to quantify parametric and pre-dictive uncertainties associated with the choice of repre-sented species in rate-controlled constrained equilibrium(RCCE) reduced models. Shock-tube experimental mea-surements of hydrogen-air ignition delay times are used toinform the candidate model classes, which are then rankedquantitatively based on closeness of fit as it is balancedwithin the model selection framework via penalization ofparametric complexity. It is found that as model size in-creases the best representations given the data form a chainwith root H2-O2-H. Therefore, they can be successivelyconstructed by adding the species that maximize the likeli-hood to this root. Finally, predicted ignition delay times is-sued by the ranked model classes are compared to those ob-tained using detailed mechanisms. It is shown that, whilesome detailed mechanisms fail to reproduce the experimen-tal data, RCCE reduction alleviates this mismatch.

Esteban Cisneros-GaribayUniversity of Illinois at [email protected]

1R.L. Gordon, A.R. Masri, E. Mastorakos, Combust. Flame,155, 181–195.

2P.R. Medwell, P.A.M. Kalt, B.B. Dally, Combust. Flame,152, 100–113.



CP16

pyMARS: A open software package for chemicalkinetics model reduction

Chemical kinetic models play a crucial role in the simula-tion of combustion. They provide a model of the chem-ical reactions present, and the species contained in thosereactions. Detailed mechanisms can contain hundreds tothousands of independent species, and thousands to tensof thousands of reactions. Because the computational costto perform simulations using these models can become im-practical, model reduction plays an active part in enablingfuture research. This presentation will introduce pyMARS(Python-based Model Automated Reduction Software), anopen-source software package that performs model reduc-tion using a variety of methods, using the Cantera suite tohandle chemical kinetics. These include the directed rela-tion graph (DRG), DRG with error propagation (DRGEP),DRG-aided sensitivity analysis (DRGASA), and DRGEPwith sensitivity analysis (DRGEPSA) methods. pyMARScurrently generates thermochemical data for reduction andevaluates the error of potential skeletal models using au-toignition simulations. Future versions of pyMARS willinclude additional skeletal reduction methods, and serveboth as a tool for reduction of large kinetic models and atestbed for determining optimal reduction strategies.

Parker Clayton, Kyle E. NiemeyerOregon State [email protected],[email protected]

CP16

Propagation of Kinetic Uncertainty Through Sur-rogate Subspace in Turbulent Combustion Simula-tions

In combustion simulations with uncertainty quantifica-tion, the uncertainties of elemental reactions are in gen-eral treated independent so that a large number of samplesfrom the high-dimensional uncertainty parameter space areneeded to propagate the kinetic uncertainty to global com-bustion characteristics such as the ignition delay time. Itis computationally challenging to perform so many indi-vidual turbulent combustion simulations. In this study,a novel approach is proposed to propagate kinetic uncer-tainty through constructing a one-dimensional surrogatesubspace in the parameter space to reproduce the uncer-tainty on the target quantity. Specifically, the surrogatesubspace is constructed by imposing correlations amongthe uncertainties of the elemental reactions, and the un-certainty factor of each reaction rate is tuned to reproducethe uncertainty of the target quantity using a genetic algo-rithm. We first demonstrate the construction of the surro-gate subspace for hydrogen/air autoignition processes witha 33-reactions detailed mechanism, in which artificial neu-ral network is employed to construct the surrogate modelto propagate the uncertainties in reaction rates to the un-certainties on the ignition delay time. Then the mean andvariance of the ignition delay time are specified as objective

NC17 Abstracts 59

functions for the optimization. Finally the constructed sur-rogate subspace is applied to propagate the kinetic uncer-tainty in the transported PDF simulations of Cabra flame.

Weiqi JiTsinghua [email protected]

Jiaxing Wang, Bin YangCenter for Combustion EnergyTsinghua [email protected], [email protected]

Zhuyin RenCenter for Combustion Energy, Tsinghua UniversitySchool of Aerospace Engineering, Tsinghua [email protected]

CP16

A Multipurpose Mechanism for Ethanol Combus-tion

A new and shorter multipurpose skeletal chemical-kineticmechanism for ethanol combustion comprising 80 reactionsand 32 species is presented. Literature survey identifies thestate-of-the-art mechanisms to be extensively tested in thewide range of canonical problems representative of techno-logical applications in the combustion science. The bench-mark problems are the premixed planar flame propagation(under different equivalence ratio, temperature and pres-sure), the isobaric autoignition time, and both premixedand non-premixed flame extinction in a counterflow con-figuration. The selected mechanisms are: The San Diegomechanism (SD), AramcoMech version 2.0, C1-C3 mecha-nism from The CRECK Modelling group of Milan Univer-sity (CRECK), Lawrence Livermore National Laboratory(LLNL) and the mechanism developed by MTA-ELTE Re-search Group of Etvs University (ELTE). The accuracy andcomputational cost evaluation of above mentioned mech-anisms identifies the San Diego Mechanism not only asthe most precise mechanism but also as the most conve-nient option from the point of view of computational cost.Chemistry reduction is achieved by analysing the sensitiv-ity of intermediate species to eliminate the reactions involv-ing the less reactive species. The resulting skeletal mech-anism compares favourably with the 235-step, 47 speciesdetailed San Diego Mechanism in all cases studied, reduc-ing the computational cost in more than a 50%.

Alejandro Millan-Merino, Eduardo Fernandez-Tarrazo,Mario Sanchez-SanzUniversidad Carlos III de [email protected], [email protected],[email protected]

CP16

Numerical Simulation of Counterflow DiffusionFlames of Methyl Decanoate Based on a ReducedMechanism

The growing global demand for energy, along with the envi-ronmental, economic and political issues have encouragedthe search for energy sources that can replace fossil fu-els. In this scenario, the study of oxygenated fuels toreduce engine emissions of CO, NOx, particulate matterand hydrocarbons, gains importance. Biodiesel is producedfrom vegetable oils or animal fats via the process of trans-esterification and is an alternative to the diesel derivedfrom oil. Among the advantages of using biodiesel, it is ob-

vious the great capacity of lubrication and the biodegrad-ability. As the composition of biodiesel is too complex tobe modeled directly, the studies focus on surrogates, suchas Methyl Decanoate (MD), which is a smaller moleculethat can reproduce the main features of the combustionof biodiesel. Thus, the present work aims to develop a re-duced mechanism for MD, using the techniques of DirectedRelation Graph and Sensitivity Analysis. The advantage ofusing these methods is the elimination of redundant speciesand reactions, decreasing the computational cost requiredto solve the equations of chemical kinetics. Numerical sim-ulation is performed in order to validate the reduced mech-anism, using the counterflow diffusion flame configuration,and the results compare reasonably with the experimentaldata available in the literature.

Felipe C. MinuzziFederal University of Rio Grande do [email protected]

Jean PinhoFederal Institute of Santa [email protected]

Alvaro De BortoliFederal University of Rio Grande do [email protected]

CP16

Performance of Nonstiff and Stiff Chemical Kinet-ics Integrators on Heterogeneous Processor Archi-tectures

Combustion simulations with finite-rate chemistry rely onaccurate and efficient methods for solving stiff ordinarydifferential equations (ODEs). In a typical reacting-flowsolver, the ODEs involving chemical kinetics at each spatiallocation are decoupled by operator splitting, allowing eachto be solved concurrently. Efficient ODE solvers must takeinto account both numerical efficiency as well as the avail-able thread and instruction-level parallelism of the under-lying computational hardware being used to perform thesimulations, especially on many-core coprocessors. Thistalk will summarize work on two complementary effortsto reduce the computational expense of chemical kineticson modern processing architectures. First, we will exam-ine the performance and behavior of exponential and im-plicit Runge-Kutta integrators implemented for graphicsprocessing units (GPUs). Second, we will compare the per-formance of explicit Runge-Kutta and implicit Rosenbrocksolvers implemented using both single instruction, multi-ple thread (SIMT) and single instruction, multiple data(SIMD) paradigms executed on multicore CPUs, Many In-tegrated Core (MIC), and GPU processors. Lastly, we willmake overall conclusions based on a synthesis of the re-sults, and identify remaining open questions and directionsfor future research.

Nicholas CurtisUniversity of ConnecticutDepartment of Mechanical [email protected]

Chris StoneComputational Science and Engineering, [email protected]

Chih-Jen SungUniversity of Connecticut

60 NC17 Abstracts

[email protected]


CP17

Large Eddy Simulation of Supersonic Combustionin Cavity-Based Scramjet

Due to the low residence time of the flow in high-speed com-bustors, the flame stabilization in such facilities becomesa real challenge. Cavities are considered as a promisingflameholding device as they allow for increasing the resi-dence time of the mixture. However, the resulting flow iscomplex, featuring supersonic and subsonic regions alongwith partially premixed combustion. The flame stabilitydepends on both the cavity configuration and the fuel in-jectors locations. Large eddy simulations are carried outto investigate the stabilization mechanisms at play in sucha high speed cavity combustor. The configuration recentlystudied by Tuttle et al. (JPP 2014) serves as a test-case.In this experimental set-up, velocity measurements (PIV)have been gathered for non-reactive and reactive flowswhile varying the fuel loading. Simulations are performedusing a 9 species and 10 steps reduced kinetic scheme forcombustion of ethylene (Singh et al. AIAA Journal 1994).The impact of the choice of the subgrid model for the fil-tered source terms on the flame dynamics is discussed anda comparison with the available experimental data is pro-vided.

Jiangheng [email protected]



CP17

An LES-PBE-PDF Approach for Predicting SootParticle Size Distributions in a Turbulent DiffusionFlame

In many hydrocarbon combustion devices, a major chal-lenge consists in controlling the formation, deposition andemission of soot particles. In this work, we present a com-prehensive LES-based model for predicting the evolutionof the soot particle size distribution (PSD) in a turbulentflame. From an Eulerian viewpoint, the PSD is governedby the population balance equation (PBE) which accountsfor the processes of soot nucleation, growth and, possibly,coagulation. In view of the interaction between turbulenceand chemical reactions as well as particle formation, weobtain a transport equation for the joint probability den-sity function (PDF) of the reactive scalars and the parti-cle number density. In practice, expectations with respectto the PDF are approximated by Monte Carlo estimatesbased on an ensemble of Eulerian stochastic fields whoseevolution equations are statistically equivalent to the PDFtransport equation. For the discretization along the par-ticle size coordinate, we present an explicit adaptive grid

approach which allows resolution in particle size space tobe automatically redistributed such that sharp features ofthe PSD are accurately resolved. Finally, we apply theLES-PBE-PDF model in order to analyze soot formationin the turbulent non-premixed Delft III flame. In the con-text of this test case, the predictive capability of the modelis assessed and the computational efficiency of our numer-ical solution scheme is demonstrated.

Fabian Sewerin, Stelios RigopoulosImperial College LondonDepartment of Mechanical [email protected], [email protected]

CP17

Implicit Large Eddy Simulations of Auto-Ignitionin a Temporally Evolving Mixing Layer

Strongly unsteady phenomena in reacting flows are re-garded as ones of the most difficult problems in contempo-rary CFD. They involve the interactions between turbulentflow field and emerging turbulent flame being the resultof chemical reactions. In this work we will analyse a non-premixed combustion in a temporally evolving mixing layerbetween streams of a hydrogen and air with a particularattention to auto-ignition and flame propagation. We use ahigh-order (up to 10th) code which was previously well ver-ified in gaseous shear layer flows with/without chemical re-actions. We apply Implicit-Large Eddy Simulation (ILES,Duwig et al., 2011) approach in which we analyse impor-tance of discretization method (TVD, QUICK, WENO,compact-difference) and mesh density on time and locali-sation of ignition kernel and flame development at the laterstage. We compare the results with DNS solutions obtainedon very dense meshes and with the LES-CMC simulations.The analysed problem is important both from the funda-mental and practical point of view. This work gives deepinside into the mechanism of auto-ignition and we showto what extent it is dependent on physical and numerical(modelling) factors. Among the others it is found that ina case of low temperature difference between the fuel andoxidiser the numerical approach affects the ignition signifi-cantly. On the other hand, when the oxidiser temperatureis large a modelling of chemical kinetics (mechanism) seemsto be a key factor.

Artur Tyliszczak, Agnieszka Wawrzak, AndrzejBoguslawskiCzestochowa University of TechnologyFaculty of Mechanical Engineering and Computer [email protected], [email protected], [email protected]

CP17

Large Eddy Simulations of Explosion DeflagratingFlames Using a Dynamic Wrinkling Formulation

Reliable predictions of flames propagating in a semi-confined environment are vital for safety reasons, once theyare representative of accidental explosion configurations.Large eddy simulations of deflagrating flames are carriedout using a dynamic flame wrinkling factor model. Thismodel, validated from a priori and a posteriori analysis, isable to capture both laminar and turbulent flame regimes.At early stages of the flame development, a laminar flamepropagates in a flow essentially at rest and the model pa-rameter is close to zero, corresponding to a unity-wrinklingfactor. Transition to turbulence occurs when the flame in-teracts with the flow motions generated by thermal expan-sion and obstacles. The model parameter and wrinkling

NC17 Abstracts 61

factor take higher values at these stages. Three configu-rations investigated experimentally by Masri et al. (2012)corresponding to different scenarios of flame accelerationare simulated. The first case (OOBS) is characterized by along laminar phase. In the second one (BBBS) the flame isthe most turbulent and the highest overpressure in the ves-sel is observed. For the last case (BOOS), the flame frontis relaminarized after crossing the first row of obstacles.In all configurations, large eddy simulations (LES) predictthe flow dynamics and maximum overpressure with goodaccuracy.

Pedro S. VolpianiLaboratoire EM2CCNRS, CentraleSupelec, Universite [email protected]


Olivier [email protected]

Denis VeynanteEM2C LaboratoryEcole Centrale [email protected]

CP17

Large Eddy Simulation of the Inhomogeneous In-let Jet Flame Using Regularized DeconvolutionMethod

Recently, a regularized deconvolution method (RDM) hasbeen developed to recover the signal loss in reactive scalarsat high wavenumber in large eddy simulation (LES). It isshown that RDM preserves the property of boundednessand conservation of the reactive scalars and the reconstruc-tion procedure is independent of the combustion regimes.In this study, RDM is applied as the closure model for tur-bulence flame interaction in LES. A posteriori analysis ofthe model will be conducted for a partially premixed jetflame with inhomogeneous inlets. Both reduced chemistryand tabulated chemistry will be considered in the analysis.The results will be compared against experiment, as wellas LES using flamelet progress variable approach (FPVA)and flamelet tabulated chemistry for LES (FTACLES).

Qing WangStanford [email protected]


CP17

Large Eddy Simulations of a Bluff-Body StabilizedFlame

Bluff-body flame stabilization in premixed flames has beena subject of significant technological interest in gas turbinecombustors, afterburners and industrial furnaces. A collab-orative computational-experimental effort is reported here,on simulating a series of bluff-body stabilized premixed

propane flames near lean blowoff conditions. The numeri-cal models include a large-eddy simulation for the unsteadyflow field, a reduced chemical mechanism to account forthe finite-rate propane chemistry, as well as a compositiontransported probability density function method to capturethe turbulence-chemistry interactions. Comparison on themean and rms velocity fields for both the non-reacting flowand the corresponding reacting flow will be made. Para-metric studies on the appropriate mixing models to capturethe local extinction events will be performed. Finally, thesequence of the physico-chemical events leading to the leanblowoff will be discussed.

Bifen WuUniversity of [email protected]

Xinyu ZhaoUniversity of ConnecticutDepartment of Mechanical [email protected]

Bikram Chowdhury, Baki CetegenUniversity of [email protected],[email protected]

CP18

The Role of Pressure Hessian in Premixed Turbu-lent Combustion

In turbulent premixed flames, the effects of the turbulentflow field on scalar dissipation transport are dominatedby the interplay between scalar gradients and the eigen-vectors of the strain rate. Recent work has shown thatthe pressure Hessian plays an important role in controllingthis interplay. In this work, Direct Numerical Simulationdatabases have been used to investigate the influence ofthe pressure Hessian on the alignment between scalar gra-dients and strain rate eigenvectors. These databases covera range of combustion conditions including the corrugatedflamelet and thin reaction zone regimes.

Umair AhmedUniversity Of [email protected]

Girish NivartiDepartment of Engineering,University of [email protected]

Malgorzata ZimonIBM Research UKDaresbury [email protected]

Robert ProsserDept of Mechanical, Aerospace and CivilEngineering, University of [email protected]

Stewart CantDepartment of EngineeringUniversity of Cambridge

62 NC17 Abstracts

[email protected]

CP18

Flame Structure and Chemiluminescence in Pre-mixed Flames

The quantitative use of chemiluminescence requires theknowledge of the relationship between the concentrationof excited species, accessible to measurement, with flameproperties such as the equivalency ratio, the burning rateor the heat release rate. With the aim of rigorously findingthese relations from first principles, we have analyzed, nu-merically and analytically, the distribution of the excitedchemiluminescent species OH∗ and CH∗ in steady hydro-gen and methane planar premixed flames. The key idea inthe analyses, rigorously proven, is that excited OH and CHare in steady state due to their small concentrations. Thisapproach enables the analytical description of the struc-ture of the distribution of both OH∗ and CH∗ in the flame,revealing how their concentrations are related with otherintermediate species, and ultimately of the fuel concentra-tion in the flame. In addition, this approach uncovers andclarifies aspects of the kinetics of premixed flames, whichcan significantly facilitate the computation of complex tur-bulent flames.

Jose Grana-OteroUniversity of [email protected]

CP18

Dynamics of Pulsating Planar Premixed Flames

The unsteady propagation of planar premixed flames in areactive solid is investigated with the aim of understandinghow the dynamics of pulsating fronts depends on the largesensitivity with the temperature of the overall chemicalreaction. The unsteadiness is encountered, with a super-critical Hopf bifurcation, after crossing the limit of stabil-ity. Close to this limit the oscillations are harmonic witha well defined time scale; but moving deeper into the in-stability domain these periodic oscillations soon becomecomplicated relaxational-type pulsations, characterized bylong stages with front velocities lower than the steady flamevelocity, followed by very short stages with very large frontvelocities. Deeper in the instability domain the propaga-tion becomes chaotic after a series of period doubling bi-furcations. For moderately large activation energies of theoverall reaction, the usteady flame maintains a classical,quasisteady structure, with a thin reactive layer embed-ded in reaction-free, unsteady heat-conduction layers. Thereactive layers, much thinner than the outer reaction-freelayers, are described analytically accounting for the heatconduction losses towards the reacted side of the layer. Theproblem of the unsteady propagation of the reactive frontis then reformulated considering the reaction layer as in-finitely thin with appropriate jump conditions. Propertiesof the soluitons are discussed based on the numerical re-sults

Jose Grana-OteroUniversity of [email protected]

CP18

Scalar Transport and Damkoehler’s Second Hy-

pothesis in the Thin Reaction Zones Regime

The turbulent burning velocity of premixed flames is sen-sitive to the turbulence intensity of the unburned mixture.Damkohler [Damkohler, G. (1940), Zeit. Elektro. Chem.,46(11):601–652.] put forward two hypotheses concerningthe effect of turbulence on the turbulent burning veloc-ity. The first hypothesis applies to low-intensity turbulencewhich acts mainly to increase the turbulent burning veloc-ity by increasing the flame surface area. The second hy-pothesis states that, at sufficiently high intensities of turbu-lence, the turbulent burning velocity is mainly affected byenhanced turbulent diffusivity. Most studies to date haveexamined the validity of the first hypothesis under increas-ingly high intensities of turbulence. In the present study,the validity of Damkohler’s second hypothesis is investi-gated. A range of turbulence intensities is addressed us-ing Direct Numerical Simulations spanning the entire ThinReaction Zones regime. Damkohler’s second hypothesis isfound to be strongly linked to the response of turbulenttransport within the flame.



CP18

Three-Dimensional Flame-Flame InteractionTopology for Premixed Hydrocarbon Flames

The flame-flame interaction topology for a methane-airflame is analysed using Direct Numerical Simulations(DNS). The DNS configuration consists of two flames prop-agating towards each other in a field of initially homoge-neous and isotropic turbulence. The two flames are al-lowed to interact freely and a data set containing informa-tion on the velocity, temperature, species concentration,pressure and density is obtained. Statistics on all of thepossible interaction topologies are extracted and the re-sults are compared with previous data obtained using ahydrogen-air mixture [1] R.A.C Griffiths, J.H. Chen, H.Kolla, R.S. Cant, W. Kollman: Three-dimensional topol-ogy of turbulent premixed flame interaction. Proceedingsof the Combustion Institute 35, pp. 1341-1348(2014). ].The differences between the statistical results due to thedifferent nature of a hydrocarbon fuel compared to hydro-gen are investigated. The implications for modelling offlame-flame interactions within the framework of the flamesurface density approach are discussed. A new term in themodel may be required to account for the destruction ofthe flame surface area by the flame-flame interactions.

Shrey Trivedi, Ryan GriffithsUniversity of [email protected], [email protected]

Stewart CantDepartment of EngineeringUniversity of [email protected]

CP18

Modelling of Premixed Flames in Progress-Variable Space Including Strain and Curvature Ef-

NC17 Abstracts 63

fects

Originally developed by Peters, flamelet models for non-premixed combustion have been gradually extended andimproved in various works in the recent past. In contrary,flamelet models for premixed combustion were only sub-ject to few studies, such as Lodier et al. [1] G. Lodier, L.Vervisch, V. Moureau, P. Domingo, Combust. Flame 158(2011) 2009 2016.] and Nguyen et al. [2] P.-D. Nguyen, L.Vervisch, V. Subramanian, P. Domingo, Combust. Flame157 (2010) 43 61.]. In premixed flamelet models the condi-tioning variable is the progress variable, which is a reactivescalar, as opposed to the passive scalar mixture fraction fornon-premixed flamelets. This work shows how to incorpo-rate strain and curvature in the model, which is illustratedby comparison to various well-known flame setups: the pla-nar twin-flame, the planar reactants-to-products and thecorresponding tubular flame setups. Additionally, negativestrain effects are studied which are in-accessible by conven-tional, one-dimensional flame setups in physical space, butwhich occur in turbulent flames. Furthermore, numericaldifficulties, that arise when trying to solve flamelet equa-tions in progress variable space, are examined and solutionstrategies are discussed. With this, this work further de-velops premixed flamelet models for the eventual usage inCFD in combination with flamelet tabulation strategies.

Axel ZschutschkeTU Bergakademie FreibergNumerical Thermo-Fluid [email protected]

Arne ScholtissekTU Bergakademie FreibergTU Bergakademie [email protected]


CP19

Impact of Reduction of Chemistry on Soot Forma-tion and Evolution in Laminar Flames

The numerical modeling of soot in flames is a numericallychallenging and computationally expensive task, requiringthe application of detailed kinetic mechanisms able to de-scribe the complex chemistry of aromatic species and sootprecursors (such as PAHs). In particular, if the interestis in predicting soot particles in industrial devices or inDNS (Direct Numerical Simulation) of turbulent flows, thecomplexity of the chemistry must necessarily be sacrificedby considering simplified or skeletal kinetic mechanisms.The objective of this work is to study the impact of suchchemical simplifications and reductions on the predictionof formation and evolution of soot in laminar flames. Inparticular, the analyses have been mainly carried out in1D laminar diffusion flames, by adopting two different ap-proaches for modeling the formation and evolution of sootparticles: i) the Hybrid Method of Moments (Mueller et al.2009); and ii) the Discrete Sectional Method (Saggese etal. 2015) in which soot chemistry is described through 20classes of pseudo-species involved in more than 10,000 re-actions. Then, the analysis was extended to coflow laminardiffusion flames for which experimental data are availablein the literature.

Agnes Livia Bodor

Department of Chemistry, Materials, and ChemicalEngineeringPolitecnico di [email protected]


Alessandro Stagni, Alberto CuociDepartment of Chemistry, Materials, and ChemicalEngineeringPolitecnico di [email protected], [email protected]

CP19

A New Jet-Stirred Apparatus for Chemical Kinet-ics Experiments

A novel jet-stirred reactor was designed to study combus-tion processes at low Damkhler number (Da, ratio of resi-dence time to chemical time), i.e. chemical kinetics. In thisnew design, multiple impinging turbulent jets are used tostir the mixture. The goal of this work is to identify an op-timal configuration of multiple pairs of impinging jets andoutlet ports for as a Jet-Stirred Reactor (JSR) for chem-ical kinetics experiment With this motivation, ANSYS-FLUENT computations using the RANS - Reynolds StressModel were used to simulate mixing and reaction in suchgeometries and their performance was compared to classi-cal JSR (4 Jets In Plus (+) Pattern (4JIPP) introduced byMatras & Villermaux 1973; Dagaut et al. 1986; etc.). Re-sults showed that CIAO provided far more uniform compo-sition and temperature and thereby more nearly match theidealizations assumed in well-stirred reactor theory, evenat values of Da higher than those accessible to other JSRexperiments. Moreover, the CIAO design yielded inferredreaction rate constants that were much to the actual valuesthan the classical JSR design.

Ashkan DavaniUniversity of Southern CaliforniaUniversity of Southern [email protected]

Paul RonneyUniv of Southern CaliforniaDept of Aero. & Mech. [email protected]

CP19

Origins of a Hot Spot for Inhomogeneous End-GasAutoignition in a Knocking Simulation

A mechanism for the generation of a hot spot for inho-mogeneous end-gas autoignition is identified with the re-sults of one-dimensional knocking simulations, where theNavier-Stokes equations are solved with a detailed chem-ical kinetic mechanism of n-C7H16. The present studydemonstrates that a first trigger for the generation of ahot post in end-gas regions is a compression wave generatedby the autoignition of an initial high-temperature source.The reflection of the propagating compression wave on thewall produces instantaneous temperature increase, whichis significantly higher that that in other end-gas regions.Therefore, some chemical reactions on the wall are pro-moted compared to those in other end-gas regions withthe production of larger amount of key chemical species

64 NC17 Abstracts

such as CH2O and OH. The progress of chemical reactionson the wall steadily continues until the occurrence of low-temperature oxidation and main autoignition whereas thetemperature increase is transient, which indicates the for-mation of a chemically-induced hot spot on the wall.

Hiroshi TerashimaHokkaido [email protected]

Akira MatsugiNational Institute of Advanced Industrial Scienceand Technology (AIST)[email protected]

CP19

Introducing ChemKED: A New Human andMachine-Readable Data Standard for Chemical Ki-netics Experiments

Fundamental experimental measurements of quantities in-cluding ignition delay times, laminar flame speeds, andspecies profiles serve important roles in understanding fuelchemistry and validating chemical kinetics models. How-ever, despite both the importance and abundance of suchinformation in the literature, the community lacks a stan-dard format for this data. This impedes both sharingand wide use by the community. In this talk, we will in-troduce a new Chemical Kinetics Experimental Data for-mat, ChemKED, and the related Python-based package forcreating and validating ChemKED-formatted files calledPyKED. We will also review past and related efforts, andmotivate the need for a new solution. ChemKED currentlysupports the representation of autoignition delay time mea-surements from shock tube and rapid compression machineexperiments. ChemKED-formatted files contain all of theinformation needed to simulate experimental data points,including uncertainty. ChemKED is based on the YAMLdata serialization language, and is intended as a human-and machine-readable standard for easy creation and auto-mated use. Development of ChemKED and PyKED occursopenly on GitHub. The software is released under the BSD3-clause license, and contributions from the community arewelcome. Plans for future development include extendingthe ChemKED format and PyKED package to support ex-perimental data for laminar flame speed, jet stirred reactor,extinction, and speciation measurements.

Bryan W. WeberUniversity of [email protected]


CP19

Efficient Solution Strategy for the Use of DetailedChemistry in High-Fidelity Simulations of Turbu-lent Flames

The use of detailed chemical schemes in high-fidelity simu-lations of turbulent combustion is essential for the accurateprediction of ignition, flame-stabilization and emissions.The cost of such calculations has long been considered in-tractable largely due to the small chemical time scale andthe expensive source-term calculation. To address these is-sues, a new integration scheme for the system of ODEs ispresented, which is semi-implicit and matrix-free. The re-

sulting efficient ODE solver leads to a direct approach foradaptive kinetics, which focuses on reducing the numberof reactions rather than the number of species. Minimalalternation on the existing code is required to adopt thesetechniques. The so obtained solver has space-time com-plexity that scales linearly with respect to the number ofspecies. Moreover, the solver is stable in the presence ofstiff chemistry and the error introduced by the adaptivekinetics can be strictly controlled. The effectiveness of thetechniques is demonstrated in application to various 1D,2D, and 3D cases.

Hao WuStanford [email protected]


CP19

Towards Efficient Chemistry Calculations in Com-bustion Simulations Through Dynamic AdaptiveAcceleration

The incorporation of detailed chemistry in combustion sim-ulations is challenging due to the large number of chemicalspecies and the wide range of chemical timescales, whichmay be further complicated by the transient nature of com-bustion process. The performance of acceleration methodssuch as tabulation/retrieval strategies may deteriorate dra-matically when large variation in the accessed compositionspace is presented. In this study, a dynamic adaptive ap-proach is proposed to accelerate chemistry calculations, inwhich the in situ adaptive tabulation (ISAT) or dynamicadaptive chemistry (DAC) is dynamically selected basedon the encountered composition inhomogeneity. The prin-ciple component analysis is employed to identify a low-dimensional subspace, in which the composition inhomo-geneity of the computational cells is quantified through re-constructing the probability density function of composi-tion in the reduced subspace. ISAT is invoked for regionswith high probabilities to avoid unnecessary tabulationsthat would be rarely reused. DAC is employed to acceler-ate chemistry calculations for the remaining cells/particlesby invoking on-the-fly reduction to generate small skeletalmechanisms for local thermo-chemical conditions. Besides,the consistent error control of ISAT and DAC is also ad-dressed so that only one error tolerance is needed for thesetwo methods. The proposed approach is validated in en-gine simulations and the performance is analyzed.

Wenwen XieCenter for Combustion Energy, Tsinghua UniversitySchool of Aerospace Engineering, Tsinghua [email protected]

Zhen LuCenter for Combustion Energy, Tsinghua [email protected]

Zhuyin RenCenter for Combustion Energy, Tsinghua UniversitySchool of Aerospace Engineering, Tsinghua University

NC17 Abstracts 65

[email protected]

CP20

Impact of Numerical Discretization and FilterShape on Large-Eddy Simulations of TurbulentPremixed Flames

Large-Eddy Simulations (LES) provide a computation-ally feasible approach for representing important time-dependent phenomena associated with reactive flow, suchas ignition, shock- and acoustic-related instabilities, andflame blow-out. Of particular importance is the develop-ment of suitable sub-grid scale (SGS) models that can cor-rectly capture the above phenomena in compressible reac-tive turbulence. However, recent studies have highlightedan increased sensitivity to numerical schemes employed inreactive-LES [Cocks et al., Towards Predictive ReactingFlow LES, AIAA 2014-0826]. Addressing such numericalissues is a necessary precursor to SGS model developmentstudies. The present work thus directly considers the im-pact of the numerical discretization scheme on LES solu-tion accuracy, relative to an explicitly defined filter. No-tably, physical model errors are eliminated by providingconsistent closure terms, that are derived from an accom-panying filtered DNS computation. A statistically planarturbulent premixed flame is considered for cases spanningthe corrugated flame and broken reaction zone regimes,and effects of the numerical scheme relative to the LESfilter (e.g.: spectral shape, characteristic width) are inves-tigated by means of planar 2D spectra, energy budgets andcomparisons to the filtered reference (DNS) solution.

Ayaboe K. [email protected]

CP20

Temperature Consistency Preservation in LargeEddy Simulation-Filtered Mass Density Function(LES-FMDF) Methods for High-Speed Flows

A scalar filtered mass density function method (SFMDF)preserving temperature consistency has been developed forhigh-speed especially supersonic flows. In this method, theeffects of the compressibility and viscous dissipation areadded to the source terms of the sensible enthalpy formu-lation. This method is coupled with LES and implementedthrough a hybrid Lagrangian Monte Carlo/finite-differenceprocedure. It is found that the compressible source term forthe SMFDF obtained by LES shows obvious errors alongdiscontinuities. To tackle this problem, the concept of par-ticle temperature consistency (PTC) is devised similar tothe previous one of particle mass consistency (PMC). ThePTC problem is studied and then several primary princi-ples are proposed for LES-FMDF to reach a good consis-tency even along discontinuities. Based on these principlesand other considerations, the source terms of the sensibleenthalpy in the FMDF are modeled and computed in anovel perspective. This new LES-SFMDF method is usedfor simulations of flows in a shock tube and flows in a sub-sonic temporally developing mixing layer. The new sourceterm calculation method is compared with the previousscheme in the simulations, the results of which show favor-able agreement with LES especially when discontinuitiesexist. This method also demonstrates robustness when var-ious particle numbers are conducted.

Lin Zhang, Jianhan Liang, Mingbo Sun, Hongbo WangScience and Technology on Scramjet Laboratory

National University of Defense [email protected], [email protected], [email protected], [email protected]

CP20

Application of Discontinuous Galerkin Methods forLES Predictions of Turbulent Flames

This talk focuses on the development of a high-order dis-continuous Galerkin (DG) method for application to chem-ically reacting flows. To enable these simulations, sev-eral algorithmic aspects are addressed, including the time-integration of multi-step chemical reactions, the incorpo-ration of detailed thermo-viscous transport properties, andthe stabilization of high-order solution representation. Ascalable parallel DG solver is developed based on this al-gorithm development and applied to LES predictions ofturbulent flame. As an example, this talk will cover theLES study of a turbulent bluff-body stabilized propane/airpremixed flame. The simulation results for cold-flow andreacting conditions are reported and compared to experi-mental data.

Yu LvStanford [email protected]


CP20

The Filtered Wrinkled Flame (FWF) Model forLarge-Eddy Simulation of Turbulent PremixedCombustion

Many models for combustion LES, well suited to capturethe turbulent flame front displacement speed, do not pre-dict the filtered turbulent flame brush. In this context, thisarticle proposes an analysis of the impact of the flame sub-filter wrinkling level on the filtered flame thickness basedon the method of manufactured solutions. Three control-ling parameters are identified: i) the flame filter size, ii)the sub-filter flame wrinkling and iii) the number of flamepatterns contained within the sub-filter volume. These pa-rameters are well defined and several models are availablein the literature for the two latters. Then, a new turbulentcombustion model is proposed following this concept: TheFiltered Wrinkled Flame (FWF) model estimates the un-closed terms of the filtered progress variable equation byexplicitly filtering 2-D wrinkled flames for different filtersizes and different wrinkling levels. An a priori validationis conducted by comparing the sub-filter PDF provided bythe model to an existing DNS database. An a posteriorivalidation is then performed on 1-D filtered flames and inthe Large-Eddy Simulation (LES) of a semi-industrial swirlburner and of a pulsed turbulent premixed flame anchoredat a triangular flame holder. Results are in good agreementwith the experiments and validate the proposed method-ology. The influence of the flame pattern period at thesub-filter scale is observed and discussed.

Vincent R. MoureauCORIA Laboratory - CNRS UMR6614Universite et INSA de [email protected]

Renaud Mercier

66 NC17 Abstracts

SAFRAN Tech, [email protected]


CP20

Sub-Grid Scale Modeling of the Equation of Statefor Fully Compressible Combustion LES

In Large Eddy Simulation of multicomponent and fullycompressible flows, formally the pressure is obtained af-ter filtering the equation of state. In practice, correla-tions between density, species and temperature are usu-ally neglected to compute the filtered pressure from theresolved fields. The conditions under which this hypoth-esis is valid are discussed from simulations of hydrogen-oxygen combustion performed with a fully compressibleflow solver (SiTCom-B), including detailed chemistry andcomplex transport. Analysing one-dimensional and three-dimensional H2/O2 space- filtered flames, it is found thata large part of the error introduced by the lineariza-tion of the equation of state can be counterbalanced byexpressing the mean molar weight of the mixture withthe Reynolds filtered species mass fractions, instead ofthe density weighted ones. An approximate deconvolu-tion/filtering procedure is then discussed to estimate theReynolds filtered mass fractions from the density weightedmass fractions, which are the transported quantities in LESflow solvers.




CP20

Impact of Radiation Modeling in Large Eddy Sim-ulation of a Turbulent Sooting Diffusion Ethylene-Air Flame

Soot modeling is today recognized as an extremely chal-lenging problem in turbulent combustion due to the stronginteractions between turbulence, chemistry and particles.In addition, a non-linear coupling exists between soot andradiation due to the high radiative contribution of soot tothe total heat transfer.A Large Eddy Simulation of a turbulent sooting diffusionflame is performed based on state-of-art modeling for thegaseous phase, using a non-adiabatic flamelet progress vari-able approach combined with a relaxation model for PAHs,and for the solid phase, employing a detailed sectionalmodel with a subgrid model accounting for intermittency.For simplicity and to reduce the computational cost,the optically thin model is generally considered for bothgaseous and solid phases. The objective here is to iden-tify the impact of this assumption by using a Monte-Carlosolver, which accounts for the re-absorption phenomenonby solving the radiative transfer equation, and provides

a detailed description of radiative properties: (1) a de-tailed CK-model for the gaseous phase; (2) a wavelength-dependent refractive index and morphological dependentradiative properties for soot particles.For each step, results on temperature and soot volume frac-tion are compared to the optically thin solutions and toexperimental data, the different radiative contributions arequantified and impacts on both quantities are evaluated.

Pedro RodriguesLaboratoire EM2C, CNRS, CentraleSupelec,Universite [email protected]



Olivier Gicquel, Nasser DarabihaEM2C LaboratoryEcole Centrale [email protected], [email protected]

CP21

Eulerian-Lagrangian Simulation of Non-SphericalBiomass Particles in Turbulent Flow

Most of the current computation fluid dynamics (CFD)simulations of biomass combustion and gasification treatpulverized biomass particles as spherical particles with ei-ther same diameter or same equivalent volume. However,pulverized biomass particles as employed in gasificationand combustion furnaces are typically highly non-spherical.From non-reacting flow simulations it is shown that thepredominant elongated needle-like biomass particles haveunique trajectories affecting also thermodynamics proper-ties in the furnace. Thus, CFD simulation results withthe spherical particles assumption may differ significantlyfrom what is found in experiments. In this work, an ellip-soidal point-like particle model has been implemented intothe open source CFD platform OpenFOAM to investigatethe velocity and spatial distribution of biomass particle inturbulent reacting channel flow.

Ning Guo, Tian Li

Norwegian University of Science and Technology (NTNU)[email protected], [email protected]

Terese LovasNorwegian University of Science and [email protected]

CP21

Collaborative Simulations and Experiments for De-velopment and Uncertainty Quantification of a Re-duced Char Oxidation and Gasification Model inOxy-Coal Combustion Conditions

The development of reduced physics models with quanti-fied model-form uncertainty is desirable to overcome thechallenges of performing LES of industrial coal-fired boil-ers. Reduced models must ensure the main features ofthe detailed models and the capability of bridging differ-ent scales and being predictive. A tight coupling of sim-

NC17 Abstracts 67

ulation and experiments is necessary to ensure predictiv-ity with uncertainty quantification for a reduced model.This work proposes a combined experimental/numericalmethodology that uses data collaboration to derive a re-duced char-combustion model describing reactions betweenchars carbon and O2, CO2 and H2O reagents in oxy-coalconditions. A valuable evaluation of uncertainty in thedata, in the model form and in the model parameters hasbeen performed. The dataset is provided by the experi-ments carried out in a laminar entrained flow reactor op-erated by Sandia National Laboratories. The methodologyinvolves the use of so-called instrument models to includeall the physical sub-models and the sources of uncertaintyconsidered in the experiments and in the numerical sim-ulations and affecting the main quantities of interest, e.g.reaction rates. The quantified uncertainty in the instru-ment models provided the range of uncertainty for the re-duced char combustion model. Then, the reduced modelwith quantified uncertainty has been validated against theexperimental data.

Salvatore IavaroneUniversite Libre de [email protected]

Benjamin IsaacInstitute for Clean and Secure Energy, University of [email protected]

Sean SmithThe University of [email protected]

Philip J. SmithUniversity of [email protected]

James OrelukUniversity of California [email protected]

Andrew PackardU of California at [email protected]

Michael FrenklachUniversity of California at [email protected]


CP21

Scalar Gradient Statistics for Regime IndependentModeling

One of the few modeling approaches of turbulent combus-tion that have the promise of being regime-independentis the transported probability density function (TPDF)method. A central unresolved issue with the TPDF meth-ods is the modeling of the mixing term that requires a clo-sure of a reacting scalar dissipation rate as well as a mixingrule. A method based on the joint PDF of the scalar andits gradients is proposed here to provide a closure for thescalar dissipation rate. The resulting TPDF equation en-capsulates the influence of the turbulence mixing and thechemical reactions on the evolution of the scalar gradient in

separate terms. Therefore, the interplay between the twocan be systematically captured across regimes spanning lowto high Damkohler numbers. An a-posteriori study is per-formed to assess the scalar gradient joint T-PDF model-ing using statistically one-dimensional turbulent premixedflame DNS data sets. The DNS data sets are chosen to spanthe corrugated and thin reaction zones regimes in multipleconfigurations. The a-posteriori assessment is systemati-cally performed by gradually expanding the terms that aremodeled versus those that are provided from the DNS.

Hemanth KollaSandia National [email protected]

Hasret TurkeriDepartment of Mechanical EngineeringUniversity of [email protected]

Xinyu ZhaoUniversity of ConnecticutDepartment of Mechanical [email protected]

CP21

Eulerian-Lagrangian Simulation of Thermochemi-cal Degradation of Thermally Thick Biomass Par-ticles

Devolatilization is a crucial step in the processes ofthermal-chemical conversion of biomass. Thermal degrada-tion of the biomass are influenced by whether the particlesare thermally thick or thin. Due to the inherent physi-cal properties, it is difficult to prepare small particles ofbiomass especially for the lignocellulosic biomass. There-fore, temperature gradients within biomass particles shouldalso be considered when simulating high-temperature con-version of biomass. In this study, a computation fluid dy-namic (CFD) model is developed to simulate thermochem-ical degradation of biomass particles in a wide range ofBiot number. A particle sub-model proposed by Strm andThunman has been implemented into an existing Eulerian-Lagrangian CFD model within the OpenFOAM frame-work. The particle sub-model resolves the gradients of tem-perature and species inside a particle with three distinctlayers: moist wood, dry wood, and char. It is found thatdepending on the Biot number of biomass particle, tem-perature gradients inside particle vary differently. For theparticle with a large Biot number, significant temperaturegradients lead to the simultaneous drying and devolatiliza-tion. Such phenomenon is not possible to be predicted withthe assumption of zero temperature gradients inside par-ticle, which is usually applied in the Eulerian-LagrangianCFD model. The developed CFD model is also examinedby a detailed comparison with experimental data.

Tian LiNorwegian University of Science and Technology (NTNU)[email protected]


CP21

Improvements to Photon Monte Carlo Radiation

68 NC17 Abstracts

Solver for Combustion Simulations

Importance of accurate radiation modeling in combustionis often undermined by the computational complexity of ra-diation solvers. The photon Monte Carlo (PMC) methodwith line-by-line (LBL) spectral data provides the mostaccurate and robust radiation solver. But PMC/LBL hashigh computational cost due to ray tracing and large mem-ory requirements due the LBL database (of the order of fewGB per processor). In this work we present three noveltechniques to improve time and memory requirement forPMC/LBL in combustion simulations with parallel scala-bility in mind. The first improvement utilizes a POSIXmemory map (MMAP) based parallel memory manage-ment algorithm, where the LBL database is accessed onlyon a need-to-know basis and is shared efficiently across pro-cessors. The advantage of this method increases with thenumber of processors per core. The second improvement isa deferred ray tracing approach for PMC, which reduces thegranularity of data transfer across processor boundaries ateach time step, thereby increasing parallel efficiency. Thethird improvement introduces a new algorithm for interac-tion between rays and participating media, if the mediumis modeled using a Lagrangian framework. Preliminary re-sults suggest roughly a factor of three reduction in memoryrequirement per processor in parallel runs, at least 15% in-crease in scaling efficiency, and significant improvement incomputational time for ray-medium interactions.

Somesh P. RoyDepartment of Mechanical EngineeringMarquette [email protected]

Steffen WeiseTU [email protected]

Ankur GuptaFM [email protected]

Michael ModestUniversity of California [email protected]


Daniel C. HaworthPennsylvania State [email protected]

CP21

Systematic Error Analysis and Error Reduc-tion of Interpolation-Based Moment Methods(MOMIC/HMOM) for Statistical Soot Modeling

Interpolation-based moment methods such as the Methodof Moments with Interpolative Closure and the HybridMethod of Moments are widely used statistical approachesto describe aerosol dynamics such as soot evolution.When performing numerical simulations, typically trans-port equations are solved for a few low order integer mo-ments of the soot Number Density Function, and fractionalor negative order moments required for closure are obtainedvia interpolation or extrapolation. The errors induced by

such procedures are studied in a combination of a prioriand a posteriori analyses using Monte Carlo simulationsas reference solution. The effect of solving an additionalequation for the moment of order minus infinity to replacethe extrapolation of negative order moments by an interpo-lation is analyzed. It is further discussed why particularlythe evaluation of moments of orders between zero and onerepresents a challenging task and may result in a system-atic overprediction of the soot surface growth term, andwhy increasing the order of the interpolation polynomialdoes not resolve this issue. Based on these considerations,an alternative scheme for the evaluation of fractional mo-ments is proposed, which leads to reduced errors in thefractional moments and hence in the soot source terms.This error analysis and reduction is first performed for aunivariate soot model based on particle volume, and thenextended to a bivariate model based on volume and surfacearea.

Achim Wick, Manish KumarInstitute for Combustion TechnologyRWTH Aachen [email protected], [email protected]


CP22

Direct Numerical Simulation of Premixed Turbu-lent Jet Flames at High Reynolds Number

A set of direct numerical simulations of turbulent premixedjet flames at different Reynolds and Karlovitz numbers ispresented. The gas phase hydrodynamics are modeled withthe reactive, unsteady Navier-Stokes equations in the low-Mach number limit. The simulations feature finite ratechemistry with 16 species and 73 reactions and up to 22Billion grid points. The jet consists of a methane/air mix-ture with equivalence ratio φ = 0.7 and temperature vary-ing between 500 and 800 K. The temperature and speciesconcentrations in the coflow correspond to the equilibriumstate of the burnt mixture. All the simulations are per-formed at 4 atm. The flame length, normalized by thejet width, decreases significantly as the Reynolds numberincreases. This is consistent with an increase of the tur-bulent flame speed due to the increased integral scale ofturbulence. This behavior is typical of flames in the thin-reaction zone regime, which are affected by turbulent trans-port in the preheat layer. Fractal dimension and topologyof the flame surface, statistics of temperature gradients,and flame structure are investigated and the dependenceof these quantities on the Reynolds number is assessed.




CP22

Direct Numerical Simulations of Spherically Ex-

NC17 Abstracts 69

panding Turbulent Premixed Flames

Three-dimensional direct numerical simulations ofmethane-air premixed spherically expanding flamesin homogenous isotropic turbulence are conducted tocharacterize the response of the propagating flame toturbulence over a range of Reynolds numbers. Thisconfiguration is chosen due to its simplicity and oppor-tunity for comparison with experiments. A methane/airmixture with an equivalence ration of 0.7 is consideredat 4 atm with an unburnt temperature of 800K. Thegas phase hydrodynamics are modeled with the reactive,unsteady Navier-Stokes equations in the low Mach numberlimit. A newly developed skeletal kinetic mechanism,which includes 16 species and 73 elementary reactions,is used to represent methane/air reactions. Temperaturedependences of transport and thermal properties are alsoconsidered. Simulations with turbulent Reynolds numbersvarying between 60 and 220 and meshes up to 8 billionpoints are performed. Turbulent flame speeds and meanflame brush thickness are analyzed together with localflame structure and the effect of turbulence and pressureare quantified.

Romain ButtayPhysical Sciences and Engineering DivisionKing Abdullah University of Science & [email protected]


Ravi [email protected]



CP22

Direct Numerical Simulation of Flame Stabilizationover a Rectangular Cavity with Compressibility Ef-fects

Flame stabilization in scramjet combustors, which pos-sess short residence times of the order of 0.1 ms, is oftenachieved using a cavity flame holder that recirculates hotproducts of combustion including radicals. In the presentstudy direct numerical simulations (DNS) are performedto understand the stabilization of a lean ethylene-air pre-mixed flame in the shear layer above a rectangular cavity.The DNS are performed with S3D using a compressible for-mulation of the Navier-Stokes equations coupled with a re-duced chemical model for ethylene-air with 22 transportedspecies. A premixture of ethylene-air at an equivalence ra-tio of 0.4 is advected into the domain at a Mach number of0.6. Both laminar and turbulent profiles at the inflow areconsidered in the DNS. Flame stabilization is found to besignificantly affected by the shear flow dynamics betweenthe main flow and the cavity flow, while the recirculationflow pattern within the cavity is dictated by its aspect ra-tio. The stabilization mechanism is quantified in terms ofrelevant non-dimensional parameters and statistics will be

presented regarding the detailed interaction between theflame and flow structures.

Aditya KonduriSandia National [email protected]

Andreas RauchUniversity of [email protected]

Hemanth KollaSandia National [email protected]

Harsha ChelliahUniversity of [email protected]



CP22

Direct Numerical Simulations of Forced IgnitionBehind a Backward Facing Step in Subsonic Flow

A backward facing step (BFS) is a canonical configura-tion used to investigate flow separation which may lead torecirculation and vortex shedding. These features are rel-evant to a wide range of engines such as gas turbines andRAM/SCRAM jet engines where flame holding (e.g., viarecirculating flow) is required to initiate and sustain com-bustion at high speeds and short residence times. In thepresent direct numerical simulation study, subsonic flowover a two-dimensional BFS is used to study the processof flame stabilization/blow-off following forced ignition. Amean turbulent inlet profile with premixed reactants wasselected in order to isolate the unsteadiness caused by themean flow from the influence of turbulent fluctuations andfuel stratification. After the flow becomes fully-developed,periodic vortices are shed and advected out of the domain.The vortex shedding introduces unsteadiness that affectsthe size of the recirculation zone and the location of theflow reattachment. Ignition kernels are imposed on thedeveloped flow and several parametric variations are con-ducted that investigate the interactions between the igni-tion kernel and mean flow unsteadiness. The nature ofthese interactions aid in defining ignition success criteria.Ignition success is found to depend upon many factors, in-cluding: ignition timing, ignition location, ignition energy,equivalence ratio, and vortex-to-vortex variability.

Alex KrismanCombustion Research FacilitySandia National [email protected]

Aditya KonduriSandia National [email protected]

Jacqueline ChenCombustion Research Facility

70 NC17 Abstracts

Sandia National [email protected]


CP22

Direct Numerical Simulation of Two-Phase Flowswith Phase Change in Subcritical and SupercriticalRegimes

This study introduces a method to treat interfaces in a mul-tiphase flow with phase changes conserving typical DirectNumerical Simulation (from the turbulence point of view)resolution while its applicability to Large-Eddy Simulationis under investigation. This method allows the simulationof such flows with real gas thermodynamics for a wide rangeof regimes, from a subcritical two phase flow where thecapillary dynamics pilot the system through the surfacetension to a supercritical fluid where such effects disap-pear. The thermodynamic consistency of the method, akey element, has been thoroughly investigated and demon-strated using canonic mono-dimensional cases. The modelis shown to adapt to the regime, to perfectly retrieve thesaturation values and to capture and preserve the inter-face dynamics, without the need of any additional ad-hocinformation. This method has been implemented in thecode AVBP, developed by CERFACS and IFPEN, to per-form two-dimensional simulations and has been validatedtrough the study of the dynamics of droplets out of equi-librium. Finally, going towards applicative cases such ascryogenic rocket jets, the model has been used to simu-late a mixing layer between two phases with a transitionbetween subcritical and supercritical regimes.

Davy NayigizenteEM2C [email protected]



CP22

Direct Numerical Simulation of Particle Burningfor Pulverized Coal Combustion

Pyrolysis, volatile ignition and char conversion stronglyaffect the characteristics of pulverized coal combustion(PCC). We perform three-dimensional Direct NumericalSimulation (DNS) of the pyrolysis and combustion of parti-cles undergoing PCC, resolving all relevant flow and flamescales and providing detailed information on small-scaleprocesses which occur on the sub-grid of Large Eddy Sim-ulations (LES). In our DNS pyrolysis is described by ageneric boundary condition at the particle surface that ac-counts for both convective and diffusive phenomena. Sub-sequent to pyrolysis, heterogeneous reactions are consid-ered, accounting for CO/O2 production/consumption ratesat the particle surface. The heating rate history of the par-ticle is obtained by solving for intra-particle heat transferand heat exchange between the particle and its surround-ings. The time evolution of volatile release is captured

by using the particle temperature to calculate the pyrol-ysis rate from a single kinetic rate law with CPD-fittedparameters. In the DNS pyrolysis and combustion of se-lected particles from an LES of the semi-industrial IFRFcoal furnace #1 are characterized. The LES provides par-ticle number density, particle trajectory, velocity statistics,turbulence scales and surrounding gas composition for theDNS. In turn, the DNS is performed on a computationaldomain of typical LES cell size and yields crucial sub-gridinformation to improve PCC-LES models.

Oliver T. SteinStuttgart UniversityInstitute for Combustion [email protected]

Giovanni-Luigi Tufano, Andreas KronenburgInstitute for Combustion Technology (ITV)Stuttgart [email protected], [email protected]

Martin RiethUniversity of [email protected]

Andreas KempfDuisburg-Essen [email protected]

Michele VascellariVirtuhcon, Chair of Numerical Thermo-Fluid DynamicsTU [email protected]


CP23

Soot Formation Prediction of the CombustionField of 4 KW Pulverized Coal Jet Burner bythe Large Eddy Simulation with the Tabulated-Devolatilization-Process (TDP) Model

Pulverized coal combustion is used in the majority of coal-fired thermal power plants. To operate the coal-fired ther-mal plants efficiently and to reduce the emissions of envi-ronmental pollutants, the understandings of the phenom-ena inside the furnace is important. Since it is difficultto measure the temperature and chemical species concen-trations and particle behaviors inside the actual large scalefurnace for the understandings of the phenomena inside thefurnace, the numerical simulation has been expected to beuseful tool for obtaining such information inside the fur-nace. In particular, the large eddy simulations (LES) havebeen employed for the prediction of coal combustion fieldby some researchers to improve the calculation accuracy.Soot particle is one of the most important intermediatesubstance in the coal combustion field. However, soot par-ticle formation has not been considered in most LES of thecoal combustion field. In this study, the soot formation inthe coal combustion field was predicted by LES with thetabulated-devolatilization-process (TDP) model. The pre-dicted soot volume fraction distributions were comparedwith the measured data. The results showed that the LEScould reproduce the soot volume fraction distributions in

NC17 Abstracts 71

the coal combustion field.

Nozomu Hashimoto, Hiroyasu TakahashiHokkaido [email protected],[email protected]

Hiroaki WatanabeDepartment of Mechanical EngineeringKyushu [email protected]

Ryoichi KuroseKyoto [email protected]

Osamu FujitaHokkaido [email protected]

CP23

Turbulent Reacting Hydrogen-Enriched Methane-Oxy Flames in a Swirl-Stabilized Gas TurbineCombustor

The study presents numerical investigation of oxy-combustion H2-enriched-CH4 diffusion flames in an atmo-spheric pressure swirl stabilized gas turbine model com-bustor. The flames characteristics in terms of tempera-ture and species distributions, structures and flow fieldsare studied numerically over ranges of operating param-eters. The effects of equivalence ratio, oxidizer compo-sition, H2-enrichment and swirl vane angle on flame sta-bility, temperature distribution and flow field are stud-ied in details. The swirl number considered is 1.10 withcorresponding swirl vane angle of 55o. ANSYS Fluentwas used to perform the numerical study and the modelsadopted are; k-e (standard), discrete ordinate (DO), eddy-dissipation-concept (EDC) for turbulence, radiation, andspecies transport. Combined modified Jones-Lindstedt re-action mechanism and Marinov reaction mechanism for H2were considered as reaction mechanism for the numericalstudy. The numerical results are in good agreement withtheir corresponding experimental data. It was observedthat utilizing H2enriched-CH4 improves the flame stabil-ity. The numerical results showed that oxy-fuel combustionof H2-enriched-CH4 is not achievable at an equivalence ra-tio of 0.95 and above due to stability issues. The stabilityis highly enhanced by the corresponding formation of innerrecirculation zone. A swirler with swirl vane angle of 65oachieved better stability limits of the gas turbine combus-tor.

Medhat A. NemitallahKing Fahd University of Petroleum and [email protected]

Mohamed Habib, Syed Said, Mansur Aliyu, Sherif SeifEldinKing Fahd University of Petroleum and MineralsDhahran, Saudi [email protected], [email protected],[email protected], [email protected]

CP23

Dynamics of a Transcritical Coaxial Flame Submit-ted to Fuel Injection-Rate Modulations: Analysisof the Generation of Heat-Release Rate Unsteadi-

ness and Low-Order Modeling

The present study is motivated by the need for im-proved understanding and modeling capabilities for high-frequency combustion instabilities in liquid-rocket engines.It is established that acoustic pressure fluctuations withinthe combustion chamber or the engines feeding systemcan induce temporal modulations of the propellants injec-tion velocities. The dynamic response of a transcriticalcoaxial flame to such velocity modulations is here investi-gated through large-eddy simulation (LES). The annularfuel stream is acoustically modulated at several frequen-cies. It is shown that the heat-release rate distribution ishighly correlated to the flame stretch rate perturbationsinduced by the modulation. The temporal response ofthe total heat-release rate strongly depends on the mod-ulation frequency and a classical low-pass behavior is ob-served for the response amplitude. The phase-lag provesto evolve linearly with the modulation frequency. Thethermo-acoustic contribution to the acoustic energy budgetdepending largely on the heat-release rate/pressure phase-lag, this mechanisms phase-lag is then one of the key pa-rameters for the prediction of combustion instabilities. Alow-order model that reproduces this mechanism is pro-posed, and the resulting model transfer function is suc-cessfully confronted to the flame transfer function samplesobtained from the various LES computations.

Robin NezLaboratoire EM2C, CNRS UPR288, CentraleSupelec,Universite [email protected]


Manuel Gonzalez-Flesca1) Laboratoire EM2C, CNRS, CentraleSupelec,Universite Paris-Saclay 2) CNES [email protected]

Sebastien CandelLaboratoire EM2C, CNRS, CentraleSupelec,Universite [email protected]


CP23

A Numerical Study of Hot Spot Ignition at RapidCompression Machine Conditions

Non-uniform, or mild ignition, can sometimes be observedduring rapid compression machine and shock tube exper-iments. This form of ignition can be caused by, amongother things, thermal inhomogeneities, which lead to flamekernel initiation, growth and propagation. The end(wall)gas can be compression heated by the propagating flameuntil autoignition ensues. This is observed in the pressurerecords as a slow pre-ignition heat release leading to short-ened ignition delay times, as well as optically via schlierentechniques and natural chemilluminescence direct observa-tion of heterogeneous flame propagation. Simulations inthe present study systematically investigate effects of ther-mal inhomogeneities on syngas ignition behavior at condi-tions where mild ignition has been observed in experiments.

72 NC17 Abstracts

Mild ignition is found to be affected by properties of themixture (homogeneous ignition, laminar flame speed, ther-mal and mass transport) as well as the size and intensity ofthermal inhomogeneities, which can be influenced by theoperating characteristics of the facility.

Jeffrey SantnerArgonne National [email protected]

CP23

Numerical Investigation of Flame Flashback in anEthylene-Fueled Scramjet Combustor at Mach 5.5Flight Condition

Flame flashback inside an ethylene-fueled scramjet combus-tor is investigated in Mach 2.52 facility with the stagnationtemperature of 1460K. The equivalence ratio f of ethylene is0.24. Experimental data suggests that the flame flashbackprocess contains strong flame triggering and flame flash-back. Fuel injection upstream of the cavity flameholderproduces a premixed region and a rapid flame flashbackoccurs against the incoming supersonic flow. The flash-back develops explosively from the cavity pilot flame atregular intervals. For numerical comparison, three inflowboundary layer thickness, d=0mm, 1.5mm and 3mm re-spectively was considered. Simulation suggests that cavitystrong flame triggering is related to the interaction of thejet plume with the cavity downstream flow. For d=1.5mmand 3mm, strong flame is triggering and moves back tofuel jet while flame stays in the cavity shear layer all thetime for d=0mm. The observed flame triggering is mucheasier for thick boundary layer since the turbulence level isincreased downstream of the cavity aft wall as the inflowboundary layer thickness increases. Flame spreads alonga fuel/air premixed region from the injection to the cavityflameholder and demonstrates a fast flame flashing-backprocess. The pre-combustion shock is pushed upstreamand interacts significantly with the boundary layer, whichprovides a more appropriate low-speed and high tempera-ture region for flame flashback.

Mingbo SunScience and Technology on Scramjet LaboratoryNational University of Defense Technologywind [email protected]

Jinshui Wu, Xingda CuiScience and Technology on Scramjet Laboratory, [email protected], [email protected]

Hongbo WangNational University of Defense [email protected]

Jianhan LiangScience and Technology on Scramjet Laboratory, [email protected]

CP23

Numerical Study on Combustion Structure in aCavity-Based Supersonic Combustor

Large eddy simulation (LES) has been carried out to inves-tigate a supersonic combustor with hydrogen injection up-stream of a cavity flameholder, where a Reynolds-AveragedNavier-Stokes (RANS) model is used for near-wall treat-

ment. The results indicate that both autoignition andflame may be significant in this cavity-stabilized combus-tion with moderate total temperature (1486K). In the in-teractional regions between the fuel jet and the cavity shearlayer, autoignition first occurs in the partially premixedregions within/under the fuel jet and then evolves intopremixed flames that are stabilized by the cavity. Thus,the combustion around the cavity corresponds to that ofautoignition-assisted premixed flames. The oxygen in thenear-wall regions is then consumed quickly by these fuel-rich premixed flames so that only the surplus fuel and com-bustion products/radicals exist within/under the fuel jet inthe zone downstream of the cavity, where diffusion flamesare formed in the periphery of the fuel jet and stabilized bythe upstream premixed combustion. Moreover, the simula-tion shows that temperature and velocity fluctuations lev-els can reach up to 20% – 40% while species fluctuationslevels may be higher.

Hongbo WangNational University of Defense [email protected]

Mingbo Sun, Chaoyang Liu, Peibo LiScience and Technology on Scramjet LaboratoryNational University of Defense Technologywind [email protected], chaoyangliucn@1,[email protected]

CP24

A New Jet-Stirred Apparatus for Turbulent Pre-mixed Flame Experiments

A new jet-stirred chamber (JSC) design incorporating mul-tiple impinging turbulent jets is proposed as an appara-tus for the study of turbulent premixed flames. ANSYS-FLUENT computations employing the RANS - ReynoldsStress Model were used to simulate the flows and identifyan optimal configuration of jets and outlet ports providingthe most nearly ideal flow, i.e. homogeneous and isotropicwith large turbulence intensity compared to the mean ve-locity. Results showed that a configuration of 8 jets, eachsurrounded by a concentric annular outlet, at the cornersof an imaginary cube circumscribed by a spherical chamberproduced by far the most nearly optimal flow characteris-tics. The performance of this configuration, called Concen-tric Inlet And Outlet (CIAO), was also compared quanti-tatively to two popular fan-stirred chamber (FSC) designsand CIAO JSC was found to provide far more nearly idealflow. A comparison of simulated turbulent premixed flamesat high Damkhler numbers (Da, ratio of chemical reactionrate to turbulent strain rate) in CIAO and an FSC showedthat CIAO enabled far more nearly spherical expandingflames with nearly the same inferred turbulent burning ve-locity regardless of the value of the mean progress variableused to define the flame location, whereas in the FSC therewas considerable variation depending on the definition.

Ashkan DavaniUniversity of Southern CaliforniaUniversity of Southern [email protected]

Paul RonneyUniv of Southern CaliforniaDept of Aero. & Mech. Eng.

NC17 Abstracts 73

[email protected]

CP24

Three-Dimensional Linear Eddy Modelling of Tur-bulent Hydrogen Jet Flames in Co-Flow

Continuing the work of Sannan et al. [Flow Turb. Com-bust., 2013, 90 : 189−216], a 3D modelling approach basedon the Linear Eddy Model (LEM) is presented and veri-fied. The needed fidelity is achieved through a reducedphysical/mathematical description of turbulence and its in-teractions with chemical reactions.Structurally, LEM3D involves a 3D lattice-work of orthog-onal arrays of LEM domains. The spacing of the LEM do-mains within this structure is coarse and is intended to cap-ture large-scale 3D effects through domain coupling. As in1D LEM, this formulation involves spatial rearrangementsof fluid elements (control volumes in a finite-volume inter-pretation), but extended to include transfers of fluid ele-ments between, as well as within, LEM domains. TherebyLEM3D also maintains the strict segregation of advectiveand molecular diffusive time advancement, which providesmaximum fidelity for combustion applications.In the current work, the in-house LEM3D code with full im-plementation of the CHEMKIN library and parallelization,to allow sub-cycling of LEM domain advancement, is com-pleted. The code has been coupled to the state-of-the-artflow solver, ANSYS FLUENT and shows that the coupledRANS-LEM3D tool has the potential of direct industrialapplication with the allowance for complex geometries suchas in gas turbine combustors.The model has been validated using experimental and nu-merical data from lifted turbulent hydrogen jet flames in avitiated co-flow.

Fredrik GrøvdalNorwegian University of Science and Technology(NTNU)[email protected]

Sigurd SannanSINTEF Energy [email protected]

Alan [email protected]

J.Y. ChenU.C. [email protected]


CP24

Comparisons of Flame Surface Density Measure-ments with Direct Numerical Simulations of a LeanMethane-Air Flame in High-Intensity Turbulence

The turbulent burning velocity of premixed flames exhibitsa non-linear variation under increasing turbulence intensityof the unburned mixture. This phenomenon, known as thebending effect, has not been fully explained to date. Akey aspect is the mechanism responsible for the observeddeparture from linearity. Experimental measurements ofspherically-expanding flame kernels [Bradley et al. (2013),Proc. Combust. Inst., 34:1519–1526.] point towards local

quenching as the primary mechanism of inhibition (bend-ing). On the other hand, recent Direct Numerical Simu-lations of statistically-planar flames [Nivarti et al. (2017),Proc. Combust. Inst., 36:(in press).] indicate that bendingmight be achieved in the absence of local quenching. Thepresent study investigates the underlying mechanisms bycomparing DNS data with experimental measurements ofa lean premixed methane-air flame in high-intensity turbu-lence.


Ben ThorneSchool of Mechanical EngineeringUniversity of [email protected]


Malcolm Lawes, Derek BradleySchool of Mechanical EngineeringUniversity of [email protected], [email protected]

CP24

Combustion Simulation of Transportation PackagePerformance in Severe, Long Duration Fire UsingComputational Fluid Dynamics Tools

The Nuclear Waste Management Organization (NWMO)is responsible for the long term management of Canadasused nuclear fuel. Transportation of radioactive materialmust be carried out in very robust transportation pack-ages. Transportation package robustness is demonstratedby satisfying stringent regulations set by nuclear regula-tors. The nuclear regulator in Canada, the Canadian Nu-clear Safety Commission, adopts regula-tions by the In-ternational Atomic Energy Agency. One of many demon-stration tests in the regulations subjects a transportationpackage to an 800C, fully engulfing fire for 30 minutes.That regulatory test bounds conditions in historic trans-portation fire accidents but its severity is difficult to com-municate to the general public; especially in comparisonto recent real-world transportation accidents involving se-vere fires. NWMO is building an advanced computationalfluid dynamics combustion model to simulate real-worldlong duration transportation accident fires. This fire sim-ulation model will help study transporta-tion package per-formance in hypothetical severe fires. Developing such amodel and knowledge will help bridge the information gapbetween the 30 minute regulatory thermal test and realworld long du-ration transportation accident fires. Thispaper describes the development of NWMOs combustionsimulation model in ANSYS Fluent; benchmarking of themodel against real-world test data; as well as challengesencountered and les-sons learned.

Yang SuiNuclear Waste Management [email protected]

CP24

Direct Numerical Simulations of Dimethyl-Ether

74 NC17 Abstracts

(DME)/Air Mixture Auto-Ignition with Temper-ature and Velocity Fluctuations

Direct numerical simulations (DNS) were conducted to in-vestigate the fundamental auto-ignition characteristics ofdimethyl-ether (DME)/air mixtures in the presence of ve-locity and temperature fluctuations. A main scientific ob-jective is to characterize the ignition behavior (regimes)for complex fuels exhibiting non-monotonic ignition delaytimes with temperature, namely the negative temperaturecoefficient (NTC) fuels, as the bulk mixture temperaturefalls in the low, intermediate, and high temperature condi-tions. The periodic boundary condition is imposed for allboundaries to mimic a constant volume combustion ves-sel, the Passport-Pouquet kinetic energy spectrum is usedto initialize the turbulent velocity field and a similar spec-trum method is employed for temperature fluctuations ini-tialization. A reduced 30 species DME oxidation mecha-nism is used for the chemical production rate calculations.The present study also showcases a first application of theKAUST adaptive reacting flow solver (KARFS) developedfor hybrid CPU/GPU computational hardware. Severalparametric simulations reveal different ignition behaviorranging from flame propagation to nearly homogeneous ig-nition. The effect of the intermediate chemistry at theNTC conditions on the ignition characteristics are exam-ined in detail, thereby providing insights into relevant is-sues in modern internal combustion engine development,such as pre-ignition and knock.

Xiao Xu, Bok Jik LeeKing Abdullah University of Science and [email protected], [email protected]

Ramanan SankaranCenter for Computational SciencesOak Ridge National [email protected]

Francisco PerezClean Combustion Research Center, King [email protected]

Hong ImKing Abdullah University of Science and [email protected]

CP25

Numerical Analysis of the Lagrangian ParticleTransport of a Confined Stage Can Combustor

The primary purpose of this study is the development ofPDF-type of models of the trajectories and deposition ofparticles from high-fidelity Lagrangian simulation of an in-dustrial Siemens combustor [1,2]. The test case has beenpreviously investigated by the authors [2] and good cor-relation with the experimental data was obtained at alllocations. The motivation comes from the interest in thedevelopment of atomization and evaporization models forindustrial gas turbines. Eulerian models are cheaper thanLagrangian models, but require the use of subgrid scalemodels to describe the particle trajectories. The presentwork is focused on the development of a methodology toobtain PDF models for Eulerian simulations using large-scale Lagrangian simulations in the context of LES. Thestrategy is based on analysing the fluid particles trajec-tories and elaborate PDF models that can reproduce theflow behaviour. The emphasis is given to the description of

the mixing lines, analysis of flow patterns, particle deposi-tion, Lagrangian trajectories and focus on the developmentof subgrid scale models and PDF-type of models for thisparticular configuration. Lagrangian simulations with dif-ferent number of particles and sizes will be conducted inorder to identify the main trajectories and generate PDF-type models that can be used in both RANS and LES.

Daniel [email protected]

Oriol [email protected]

Enric I. Mahiques, Lukasz [email protected],[email protected]

Mariano Vazquez, Guillaume [email protected], [email protected]

CP25

CFD Modeling of Water Mist Suppression of SolidCombustible Fires Using Firefoam

Water-based suppression systems have been frequentlyused to protect solid combustible products in warehouseoccupancies. Understanding the suppression physics canhelp design an effective fire suppression system. In thisstudy, water mist suppression of rack storage fires of a2x4 by 2 tier high fuel array is investigated. Water mistspray typically has low water delivery density and smalldroplets on the order of 0.1 mm. One of the key suppres-sion physics is direct gas-phase flame quenching. The smalldroplets evaporate quickly in a fire environment and pro-duce a large amount of water vapor. Spray evaporationcools the flame and the generated water vapor dilutes thelocal oxygen. The high velocity spray also disturbs theflame and increases the flame strain rate. These effectschange the energy balance between local heat release rateand heat loss rate, which may lead to local flame extinc-tion. In addition to flame extinction, spray wetting/coolingof the burning surfaces and radiation attenuation can alsoenhance the spray suppression effectiveness. This studytargets modeling fire suppression with the aforementionedsuppression physics in a CFD code. Specifically, gas-phaseflame extinction is modeled based on the Damkhler numberconcept and the surface wetting/cooling is modeled with athin water film flow on solid surfaces. The modeling resultsare compared against a series of full-scale suppression testswith different nozzle, drop size and pressure.

Ning Ren, Hong-Zeng Yu, Karl Meredith, Ankur Gupta,Yi WangFM [email protected], [email protected],[email protected], [email protected],[email protected]

CP25

Numerical Investigation and Optimization ofPorous Media Burners

Combustion in porous media represents a promising com-

NC17 Abstracts 75

bustion technology for achieving lower emissions, enhancedflame stabilization, and improved fuel efficiency comparedto conventional free-flame systems. In these burners, com-bustion is facilitated inside a porous matrix that is madeof a heat-conducting material to enable internal heat-recirculation and achieve super-adiabatic combustion bypreheating the unburned reactant mixture to temperaturesthat sustain chemical reactions. The objective of this studyis to computationally examine the stability of combustionin porous media burners (PMBs). To this end, low-orderand high-fidelity models are developed to enable the pre-diction of the heterogeneous combustion and conjugateheat transfer inside the porous structure. Experimentaldata from X-ray computed tomography, thermocouples,and pressure probes are used for model validation. Follow-ing the model validation, parametric studies are performedto examine the stability and emissions of PMBs over arange of operating conditions, including mass flow rates,equivalence ratios, and material properties of the porousmatrix. By employing computational optimization of poresize and pore-distribution, a new burner concept is iden-tified that exhibits superior performance properties com-pared to conventional PMB-designs in terms of pressuredrop, emissions, and flame stability. This optimized PMB-design is demonstrated experimentally to validate compu-tational predictions.

Sadaf Sobhani, Danyal MohaddesStanford [email protected], [email protected]


CP25

Numerical Simulation on Lean Premixed HighSwirl Flame Flashback

In hydrogen-rich fuel based gas turbines, the issue ofboundary layer flashback is a key safety concern. Due tothe wide flammability range of hydrogen combined withits high reactivity, a premixed flame can propagate alongboundary layers. This upstream motion can locate theflame inside the premixing chamber, which is typically notdesigned for high temperature fluids. Hence, understand-ing the physics of boundary layer flashback is important fordeveloping designs that arrest such upstream flame motion.In this work a model premixed swirl combustor, experimen-tally studied at UT Austin, is simulated using large eddysimulation methodology. A novel flame-generated mani-fold approach is used to capture the flame propagation.Flame flashback is initiated by increasing the inflow equiv-alence ratio in the experiment. To simulate this effect, avariable equivalence ratio stratified flame model is devel-oped. A flamelet-generated manifold is developed, whereeach flamelet solution is simulated by accounting for a wallheat-loss parameter. The solution is then mapped to aprogress-variable/enthalpy loss space. Different strategiesfor developing the flamelet tables are discussed in this con-text. Simulations show that flashback proceeds in the low-velocity streaks found near the wall. Further, flashbackcircumvents the swirling motion, with the flame jumpingacross streamlines. This is contrary to methane-air flames,where flashback follows the swirling motion of the fuel-airmixture.

Yihao Tang, Malik HassanalyDepartment of Aerospace Engineering

University of [email protected], [email protected]

Venkat RamanUniversity of [email protected]

CP25

Modeling of Light-Round in An Annular Combus-tor Operating under Perfectly Premixed Condi-tions

The results from the large-eddy simulation (LES) of light-round in an annular combustor operating under perfectlypremixed conditions are analyzed in order to model theflame propagation during the ignition process. In particu-lar, the absolute velocity of the turbulent flame front is akey quantity which controls the duration of the light-roundprocess. It depends on the resolved and subgrid-scale flamewrinkling but also on the gas volumetric expansion. Underthe specific configuration of an annular chamber, this ex-pansion is modified during the ignition process by the out-flow at the exhaust boundary of variable mass flow ratesof fresh and burnt gases. Considering global budgets ofspecies, mass and momentum combined with hypothesessupported by the LES results enables to quantify the cou-pling of the different phenomena that have been observedand to derive a macroscopic model for the absolute turbu-lent burning velocity. The range of validity of the model isfinally assessed for different operating points.

Maxime Philip, Ronan Vicquelin, Thomas SchmittEM2C, CNRS, Ecole Centrale [email protected], [email protected],[email protected]

Sebastien CandelEM2C, CNRS, [email protected]

CP25

Detailed Investigation of the Two-Phase ReactingFlow in An Aeronautical Test Rig

Even if a great effort has been devoted to the predictivemodeling and simulation of aeronautical-like configurationsin gaseous conditions, two-phase configurations are stillchallenging to simulate because of the complex interactionsbetween the spray, the flame and the flow field, especially ina Large Eddy Simulation (LES) context. In this work, wefocus on the description of the spray phase, by investigatingthe impact of the polydispersity on the spray flame. To doso, we compare the results obtained from a monodispersedescription and from a Multifluid approach. To ensure acorrect characterization of the chemistry, we use an analyt-ical chemistry solving for 24 species, expressly developedfor dodecane. Investigations are concentrated on the sprayand fuel distribution in the combustion chamber, as wellas on the spray-flame interactions, in order to highlight theeffects of polydispersion.

Aymeric VieLaboratoire [email protected]

Benedetta G. FranzelliEcole Centrale Paris, EM2C CNRS UPR-288

76 NC17 Abstracts

[email protected]

CP26

Adequate Techniques for the Practical Computa-tion of Optimal Estimators

Modeling unclosed terms in partial differential equationsrequires to express these terms as a function of knownquantities and typically involves two steps: First, a setof known quantities needs to be specified as input param-eters for the model, and second, a specific functional formneeds to be defined to model the unclosed terms by theinput parameters. Both choices involve a certain model-ing error, with the former known as the irreducible error.Typically, only the total modeling error is assessed, but theconcept of the optimal estimator applied here enables theseparate analysis of both the total and the irreducible error.Additionally, it enables the identification of optimal inputparameter sets for a certain model by a systematic analysisof irreducible errors. This concept has been applied in thecontext of a priori analyses of turbulent combustion mod-els as the complexity of DNS necessitates such systematicanalysis tools. So far, little attention has been paid to thetechniques themselves required for the practical computa-tion of irreducible errors. Particularly for large numbers ofinput parameters, the choice of technique strongly affectsthe outcome of the analysis so that, in this work, a compar-ison among different techniques is presented. Moreover, astrategy for the systematic reduction of irreducible errorsis discussed. The findings are applied to modeling the sootintermittency in LES using a DNS data set of a sootingtemporally-evolving n-heptane jet.

Lukas BergerInstitute for Combustion TechnologyRWTH Aachen [email protected]



CP26

Dynamics of Combustion Systems Using LyapunovAnalysis

Transient processes are an important class of combustionproblems relevant to flashback, thermoacoustic instabili-ties, ignition, relight and blow-off in gas turbines. Forsuch flows, the use of statistical tools is not optimal dueto the low frequency occurrence of key events. In order todevelop a methodology for understanding low frequencyor rare events, a dynamic systems approach is followedhere. Such techniques have been widely used for studyinglow-dimensional chaotic systems in the past. With the in-crease in computational power, there is a new opportunityto apply such methods to the high-dimensional turbulentcombustion problem. As a first step, a characterizationof rare-events is provided in terms of this dynamic sys-tems approach. Further, Lyapunov spectrum is computedfor canonical turbulent flames to understand the nature ofstrange attractors for theses systems. A method to obtainrare trajectories by conducting forced simulations is thendiscussed. Application to flame propagation in homoge-

neous turbulence is presented.

Malik HassanalyDepartment of Aerospace EngineeringUniversity of [email protected]


CP26

Stochastic Modeling of Combustion

A variety of turbulent flows both with and without com-bustion have considered. Stochastic modeling of turbulentflows is discussed in terms of velocities and compositions.Monte Carlo method and turbulent diffusion flame calcu-lation with thermo-chemical schemes involving upto threecomposition variables with finite rate kinetics is discussedin this paper.

Salam KhanAlabama A & M [email protected]

CP26

Characteristics of a Partial Premixed Bluff BodyLow NOx Burner

A novel partial premixed bluff body (PPBB) burner hasbeen investigated numerically. The burner features a frus-tum shaped bluff body that generates a flame stabilizingrecirculation zone. Hydrogen is partially premixed in anaccelerated air cross-flow before reaching the combustionzone. The burner operates at lean conditions and incor-porates internal flue gas recirculation to achieve low NOxemission levels. Experimental investigations have provengood emission-performances at laboratory scale (10 kW).However, the scalability of the burner is not well under-stood yet. Computational fluid dynamic (CFD) simu-lations have therefore been conducted to investigate thegoverning fluid and thermodynamic characteristics of theburner. The numerical model has been validated againstexperimental data obtained by 2D particle image velocime-try (PIV) measurements for cold and reacting flow con-ditions. The degree of premixing and the extent of dilu-tion due to recirculation of combustion products have beenquantified and different flame regions have been character-ized.

Christoph MeranerNorwegian University of Science and [email protected]

Mario DitarantoSINTEF Energy [email protected]


CP26

A Combination Between Two Semi-AnalyticalMethod Called ”Singularly Perturbed HomotopyAnalysis Method, (spham)” Applied to Combus-

NC17 Abstracts 77

tion of Spray Fuel Droplets

In our research we combined two well-known analyticalmethods: the Homotopy Analysis Method (HAM) and theMethod of Integral (invariant) Manifold (MIM) to inves-tigate the problems of auto-ignition of a polydisperse fuelspray. We call this combination the Singularly PerturbedHomotopy Analysis Method (SPHAM). In many cases,combustion processes are described by mathematical mod-els that includes a set of highly nonlinear differential equa-tions that are characterized by a different time scale (so-called multi-scale systems). For example, the temperatureis a fast variable, due to the Arrhenius factor, compared tothe radius evolution variable (the evaporation process). Weapply the SPHAM method to problems of thermal explo-sion in two phase combustible mixtures of gas with poly-disperse fuel droplets. We analyze a dependence of ouranalytical and/or numerical results for different practicalprobabilistic distributions of fuel droplets, that are mod-eled by continuous probability distribution functions. Byapplying the SPHAM, we derived an analytical solutionof the system for comparatively simple models of thermalexplosion and compared our results with numerical simu-lations.

Ophir NaveHashachar street 24 Beit Hakerem [email protected]

CP26

Mode Determination for Combustion Modeling inPartially Premixed Turbulent Flames

The cost of turbulent combustion simulations can bedrastically decreased by using reduced-order manifolds(e.g. flamelets) to approximate local thermochemicalstates. These manifolds are typically generated from one-dimensional flame calculations with boundary conditionsappropriate for the global combustion mode of the tur-bulent flame being simulated. For multimodal turbulentflames, the manifold must include one-dimensional calcu-lations with a range of boundary conditions correspondingto nonpremixed, premixed, and partially premixed flames.The transition between the combustion modes is specifiedthrough either a local indicator or the flamelet bound-ary conditions. In this work, a new flamelet approach formulti-modal combustion is applied in large eddy simula-tion (LES) of the Sydney jet flame with inhomogeneousinlets. A second mixture fraction is required to charac-terize the mixing within this three-stream configuration;this provides a suitable parameter to indicate the combus-tion mode and define the flamelet boundary conditions.Unlike previous mode switching models, this approach in-trinsically accounts for both multimodal combustion andthe effects of mixture inhomogeneity. It is shown thatnew approach captures the evolution from largely premixedcombustion near the nozzle to nonpremixed-like combus-tion downstream that is seen experimentally in the Sydneyflame.

Bruce A. PerryDepartment of Mechanical and Aerospace EngineeringPrinceton [email protected]

Michael E. MuellerPrinceton University

[email protected]

MS1

A Multi-Scale Model of Compaction-Driven Initia-tion of Detonation

In heterogeneous explosives, sites of high temperature andpressure, called hot spots, play a significant role in det-onation initiation. This study seeks to model hot spotsgenerated by the compaction of a granular explosive. Twoscales are considered, a macro scale modeled as compress-ible reactive flow with compaction coupled to a grain scalerepresented by a reaction-diffusion system. Well-resolvednumerical results are presented for initiation and propaga-tion of detonation.

James R. GambinoLawerence Livermore National [email protected]

Donald W. SchwendemanRensselaer Polytechnic InstituteDepartment of Mathematical [email protected]

Ashwani K. KapilaRensselaer Polytechnic [email protected]

MS1

Whole-System Detonation Modelling for PracticalApplications

Contemporary industrial combustion applications often in-volve the two-way interaction of detonation processes withgeometrically complex, several-material structures. In thiswork we present a mathematical and numerical frameworkfor multi-physics and multi-scale whole-system simulations,where the governing equations for condensed-phase explo-sives, inert fluids and elastic-plastic solids are solved si-multaneously. We focus on applications involving explicitdetonator modelling and underground charges simulationfor the generation of synthetic seismic data. Each applica-tion has its own challenges, depending on the number andtype of materials involved and governing lengthscales andtimescales.

Eleftherios IoannouUniversity of [email protected]

Louisa MichaelLaboratory for Scientific ComputingUniversity of [email protected]

Nikolaos NikiforakisUniversity of [email protected]

MS1

Propagation Limit of Detonation Waves in a Spa-tially Heterogeneous Reactive Medium with Yield-ing Confinement

The effect of two-dimensional spatial heterogeneities on thepropagation limit of detonation waves governed by single-step Arrhenius kinetics and yielding confinement is com-

78 NC17 Abstracts

putationally examined in this study. The reactive mediumconsists of a calorically perfect gas. The heterogeneitiesare implemented via introducing a spatially regular or ran-dom variation in the initial concentration of the reactant.In order to investigate the propagation limit, losses dueto lateral expansion are realized by placing an inert layerconfining the detonable mixture. The deficit in propaga-tion speed from the corresponding Chapman-Jouguet valueis expected, as a loss in momentum is experienced by thedetonation wave. A critical charge thickness below whicha steady propagation cannot be sustained is numericallydetermined. The resulting detonation speed deficits andcritical thicknesses from the simulations for the cases withhomogeneous and heterogeneous reactive media are com-pared with the analytic results obtained using a quasi-one-dimensional, ZND-like model based on the assumption of asmoothly curved detonation wave front. A percolation-likemechanism that assists a detonation wave to propagate be-yond the limit that would be encountered in a homogeneoussystem might be identified in the cases with randomly dis-tributed heterogeneities.

XiaoCheng MiMcGill [email protected]

Andrew HigginsDepartment of Mechanical EngineeringMcGill [email protected]

Hoi Dick Ng, Charles B. KiyandaConcordia University, Montreal, [email protected], [email protected]

Nikolaos NikiforakisUniversity of [email protected]

MS1

Equations of State for Predictive Modelling of Con-fined, Condensed-Phase Explosives

Modelling of detonation waves requires closure rules fordescribing the mixing of reactants and products in thereaction zone. Temperature equilibrium, heat isolationand constant volume conditions are among the possibleassumptions that can be made. If the temperature equilib-rium condition is to be implemented, equations of state ca-pable of producing thermodynamically meaningful valuesof the temperature are required. To this end, we modify ex-isting equations of state to appropriately approximate thetemperature in the reaction zone. Mechanical equationsof state of Mie-Gruneisen form are developed with exten-sions, which allow the temperature to be evaluated appro-priately. Furthermore the use of a temperature equilibriumapproximation in the context of a hydrocode requires thesolution of a non linear equation. The thermodynamicallycorrect asymptotic behaviour of the equations of state thatwe present ensures this can be solved robustly. We applythe new form of the equations of state in the context of pre-dictive simulation of detonations in compliantly confinedrate-sticks.

Simon D. Wilkinson, Nikolaos NikiforakisUniversity of [email protected], [email protected]

Louisa Michael

Laboratory for Scientific ComputingUniversity of [email protected]

MS2

Open-Source Software for Uncertainty Quantifica-tion in Reacting Flows

We present on-going work to provide open-source softwaretools to enable quantification of uncertainty in reactingflows, including statistical inversion for probability den-sity functions of parameters. We describe the Antiochthermochemistry and transport library that provides aninterface to compute kinetic rates, thermodynamics, andtransport properties. Antioch also provides an interface forcomputing solutions to zero-dimensional reactors. We alsodescribe GRINS, a multiphysics finite element frameworkbuilt on the libMesh finite element library. Within GRINS,we have deployed 1-D, 2-D, and 3-D kernels for the reactinglow Mach Navier-Stokes equations suitable for combustionflows. These kernels leverage the Antioch thermochem-istry library. We discuss how GRINS and facilitate com-putations of quantity-of-interest functionals in conjunctionwith the discrete adjoint problem for enabling adapativemesh refinement and sensitivity calculations. Finally, wedescribe on-going work to facilitate the interaction betweenGRINS and the QUESO statistical library for solving sta-tistical inverse problems. Antioch, libMesh, GRINS, andQUESO are all open-source packages, available on GitHub,and are licensed under LGPL 2.1.

Paul BaumanMechanical and Aerospace EngineeringUniversity at Buffalo, State University of New [email protected]

MS2

Multifidelity Failure Probability Estimation inCombustion Modeling

The process of robust design of combustion devices oftenrequires computing the probability of failure of the com-bustion unit. With many uncertain parameters in a com-bustion model, computing failure probabilities amounts toevaluating the expectation of the failure event, as definedby the engineer. By design, failure probabilities are small,and standard Monte Carlo estimation of the failure inte-gral requires many samples. This gets complicated by thefact that we consider cases where evaluating the QOI re-quires solving a computationally expensive model, such asa combustion model. We thus propose to use importancesampling to reduce the number of expensive model eval-uations. Using a suite of surrogate models, we evaluatethe QOI, and design a biasing distribution, that is biasedtowards failure events. The evaluation of the surrogatesis computationally cheap. With this biasing distribution,we can evaluate the original failure proability with muchfewer samples - and hence much fewer evaluations of theexpensive model - while achieving high accuracy. Numeri-cal examples on a combustion-type test problem illustrateour approach.

Boris KramerMassachusetts Institute of [email protected]

Benjamin PeherstorferACDL, Department of Aeronautics & AstronauticsMassachusetts Institute of Technology

NC17 Abstracts 79

[email protected]

Karen E. WillcoxMassachusetts Institute of [email protected]

MS2

Towards Model Inadequacy Representations forFlamelet-Based Combustion Models

Flamelet-based models are commonly used to representcombustion in RANS and LES simulations of non-premixedcombustion. These models are formulated assuming a sep-aration of scales between the chemistry and the flow, withthe chemistry assumed to be fast relative to the turbu-lence. This allows a turbulent flame to be approximatedconceptually as an ensemble of laminar flames. Even whenthis basic conceptual model is valid, to formulate a prac-tical model, a number of additional modeling choices andapproximations are made, including the choice of param-eterization of the laminar flame solution, choice of chemi-cal mechanism to generate laminar flame solutions, choiceof PDFs characterizing the ensemble, etc. These choicesintroduce model inadequacy that can lead to inaccuratepredictions. In the present talk, we explore the possibilityfor representing these model inadequacies in the context ofa RANS/flamelet model for a turbulent jet flame. It willbe shown that the uncertainty in a laminar flame library,due to either chemical parameter uncertainty or chemicalmodel inadequacy, can be effectively represented using aKarhunen-Loeve decomposition of the resulting stochasticflame solution. This representation is then exploited to de-velop a tractable representation of the model inadequacyin the flamelet model.

Todd A. OliverPECOS/ICES, The University of Texas at [email protected]

David SondakPECOS/ICES, University of Texas at [email protected]

Chris SimmonsICES, University of [email protected]

Robert D. MoserUniversity of Texas at [email protected]

MS2

Calibration of a Stochastic Operator-Based ModelInadequacy Representation for Chemical Kinetics

Two of the most prominent modeling assumptions used insimulations of turbulent combustion are the introduction ofturbulence models and reduced chemistry models. In thepresent work, we develop a stochastic model inadequacyrepresentation to quantify uncertainties due to reducedmodels in chemical kinetics. The inadequacy formulationis a generalization of previous work in which a stochasticoperator is appended to a reduced chemical kinetics modeland calibrated with data from a detailed model using aheirarchical Bayesian approach. The inadequacy formula-tion accounts for situations in which both reactions andspecies are neglected from the detailed model. The newinadequacy model was developed to be adaptive such that

it is only active when chemical reactions are taking place;otherwise the inadequacy model does not participate. Wepresent results from a perfectly stirred reactor of H2 O2

combustion. The detailed model consists of 21 reactionsand eight species whereas the reduced model uses five reac-tions and seven species. We then apply the inadequacy for-mulation to a one-dimensional counterflow diffusion flamewith H2-O2 combustion. Finally, we present preliminaryresults on using the counterflow diffusion flame and its as-sociated uncertainties from the inadequacy formulation tobuild an uncertain flamelet library for non-premixed com-bustion.

David SondakPECOS/ICES, University of Texas at [email protected]

Todd A. OliverPECOS/ICES, The University of Texas at [email protected]

Robert D. MoserUniversity of Texas at [email protected]

MS3

Direct Construction of the Steady Traveling HighExplosive Cylinder Test

The intent of high explosives (HE) is to perform work onsurrounding inert materials. In this respect, it is the HEproduct equation of state (EOS) that is important. Thisis indirectly measured through one of several experimen-tal procedures, such as the HE copper cylinder test. Inthis test, a detonation wave in the HE is allowed to reachsteady propagation while driving a copper liner. Often,such experiments are modeled with full time dependenthydrocodes, which results in hours of simulation times onsuitable computational meshes. Here, a description of asolution technique to construct the steady traveling wavesolution is presented. This may be useful in calibrating HEproducts EOS as well as for cross-verification of other hy-drocodes. The methodology takes advantage of the steadi-ness of the flow to construct the solution, thus eliminatingthe independent variable of time. A fast construction canbe achieved by marching in a single space dimension. It isconvenient to utilize streamline coordinates, as this natu-rally allows for different EOS for HE and inert materials aswell as for allowing material slip. A finite volume method-ology allows for discrete conservation of mass, momentumand energy. An approximate Riemann solver based solu-tion technique will be presented. It is shown that solutionscan be generated in a matter of seconds at very high res-olution, opening up the possibility of rapid calibration ofHE products EOS via nonlinear optimization techniques.

Tariq D. AslamLos Alamos National LaboratoryGroup WX-9, Shock and Detonation [email protected]

MS3

A Thermochemical Algorithm for CombustionModelling

A new computational tool for predicting the performance ofexplosives based on chemical composition will be presented.An equation of state for a reacting multi-component, multi-phase mixture is constructed by linking a statistical me-

80 NC17 Abstracts

chanics model of high pressure fluids with that of a solidunder pressure. The non-linear constrained optimizationproblem for the thermochemical equilibrium state of themixture is solved via a sequential quadratic programmingmethod. A novel procedure is incorporated to maintainmechanical equilibrium across phases in the mixture dur-ing this process. The resulting thermochemical code isused within the framework of Chapman Jouguet detona-tion theory to predict the ideal detonation performance ofexplosives. An extension is presented which aims to cap-ture non-ideal effects by solving a reduced system alongstreamlines.

Geraint Harcombe, Nikolaos Nikiforakis, MartinBraithwaiteUniversity of [email protected], [email protected],[email protected]

MS3

A New Approach for Cook-Off Modelling

The numerical modelling of slow-initiation or cook-off ofexplosives has been a subject of great discussion, as thedisparate timescales of the heating process and the det-onation event generate non-trivial numerical challenges.Cook-off processes involve multiple materials and phasesof matter and current numerical simulation methods of-ten rely on coupling different sets of equations to describethem separately. In this work, we adopt a mathematicalmodel able to describe both solids and fluids in a singlehyperbolic framework, including a hyperbolic subsystemfor thermal conduction, to simulate such processes. A newmethod is proposed for significantly accelerating the sim-ulation of slow cook-off on short, bounded domains: Theacoustic components of the system are approximated byassuming that the pressure roughly equilibrates on a fastertime scale than the other processes of the system, and onlya reduced subsystem is solved. Examples of applicationsof the method for cook-off modelling are presented.

Haran Jackson, Nikolaos NikiforakisUniversity of [email protected], [email protected]

MS3

Robust Multi-Dimensional Shock-Fitting

The use of shock-capturing methods in the vicinity of dis-continuities typically preclude high rates of convergence ofsolutions. This suggests that the use of a numerical schemewhich fits the shock and material interface can provide amarked improvement on the accuracy of solution. However,such methods often suffer from secondary unfitted disconti-nuities interacting with the fitted leading shock or materialinterfaces, e.g. triple points or overtaking shocks. In order,to extend the utilization for the recently developed shockand material interface fitting scheme, which is composedof fifth-order spatial and third-temporal discretizations, aswitch is added to the algorithm to locally lower the orderof the algorithm near the fitted shock when a secondarydiscontinuity is in the region. This more robust schemeis first applied to an inviscid, detonating, ideal gas prop-agating in a two-dimensional channel. It is also appliedto two-dimensional slab and axisymmetric high-explosive(HE) geometries.

Christopher RomickEureka Physics

[email protected]

Tariq D. AslamLos Alamos National LaboratoryGroup WX-9, Shock and Detonation [email protected]

MS4

Quantifying Uncertainty from Model Error in Tur-bulent Combustion Applications

We focus on quantifying the uncertainty associated withmodel error in large eddy simulations (LES) of a scramjetengine. LES models may involve different parameteriza-tions, and numerical or geometric simplifications in orderto achieve computationally tractable simulations, but er-rors are often introduced from these simplifying physical ornumerical assumptions. It is thus imperative to understandand quantify the additional uncertainty induced as a resultof using these model alternatives. We introduce a novelstrategy for model error quantification by directly embed-ding a discrepancy representation into the parameters ofthe models. Armed with higher fidelity simulation data,we then proceed by calibrating both model parameters anddiscrepancy representation simultaneously. What sets ourapproach apart is its advantages for accommodating predic-tive engineering applications: the method generates physi-cally meaningful predictions of quantities of interest (QoIs)by automatically respecting the governing equations andphysical constraints imposed in the model, and providesan intuitive platform for ”extrapolating” the model errorfor predicting new QoIs. Using a Bayesian perspective,the calibration problem is solved by combining techniquesof approximate likelihood, adaptive Markov chain MonteCarlo, and polynomial chaos expansions. Numerical exam-ples comparing static versus dynamic Smagorinsky turbu-lent models, and 3D versus 2D simulations are presented.

Xun Huan, Khachik Sargsyan, Zachary Vane, GuilhemLacazeSandia National [email protected], [email protected],[email protected], [email protected]


Habib N. NajmSandia National LaboratoriesLivermore, CA, [email protected]

MS4

Reduced-Order Modeling of Combustion Reactionsin Uncertainty Quantification

Abstract not available

Alan LattimerJensen [email protected]

MS4

Physics-DerivedModel Form Uncertainty Quantifi-

NC17 Abstracts 81

cation for Turbulent Combustion

The major challenge in turbulent combustion modeling isthe sheer number of models that are invoked, each of whichinvolves its own set of assumptions and subsequent modelerrors. Quantification of model errors is critical in assessingwhich model dominates the total uncertainty and should betargeted for future improvements. The fundamental chal-lenge in quantifying model error is in translating model as-sumptions, inherently coupled to the physics, into mathe-matical statements of uncertainty. In this work, two meth-ods are presented for deriving model error estimates di-rectly from the physics, bypassing the need for ’training’data, which can never be obtained over all regimes of in-terest. The first method, peer models, uses models withdiffering assumptions to derive an uncertainty estimate.This approach will be demonstrated to derive model uncer-tainty for the scalar dissipation rate time scale. The secondmethod, hierarchical models, uses a higher-fidelity modelto estimate the uncertainty in a lower-fidelity model. Thisapproach will be demonstrated to derive model uncertaintyfor low-dimensional manifold combustion models. The twoapproaches will be applied to a canonical jet flame con-figuration to assess the relative contributions of differentmodel errors.



MS5

Use of Uncertainty Quantification in Tools for Au-tonomous Scientific Inquiry

Generally, the process of generating kinetic data and im-proving/validating a kinetic model against data requirestime-intensive efforts from computational and experimen-tal researchers. Uncertainty quantification (UQ) of courseprovides a natural means of automating portions of thisprocess. As examples, UQ-based design of experimentsand calculations can identify the most worthwhile data togather, and inverse UQ can quantitatively improve mod-els based on data. In this regard, UQ, when coupled withautomated methods for generating data, provides a meansof significantly reducing the amount of time required togather relevant data and improve/validate kinetic models.

Michael P. BurkeArgonne National [email protected]

MS5

Global Sensitivity Analysis with Small SampleSizes for Large Scale Combustion Simulations

A version of global sensitivity analysis is developed touse for the analysis of complex chemical-kinetic models incombustion devices, such as compression-ignition engines,where typical computations take several processor weeksto complete. It is common in combustion simulations foronly a few reactions to have significant sensitivity coef-ficients and we develop procedures for small-sample sizeglobal sensitivity analysis based on this assumption. Be-cause the sample sizes are small and false positives are pos-sible, an important task of this work is calibration, which

is done on a chemical model that has been used in enginesimulations. This talk will discuss work with several collab-orators, in particular: Raghu Sivaramakrishnan, SibenduSom, Wei Liu, Rex Skodje, and Dingyu Zhou. This workwas supported by the U. S. Department of Energy, Office ofBasic Energy Sciences, Division of Chemical Sciences, Geo-sciences, and Biosciences, under Contract No. DE-AC02-06CH11357.

Michael J. DavisArgonne National LaboratoryArgonne, IL [email protected]

MS5

Providing Structure to Experimental Data: ALarge Scale Heterogeneous Database for Collabo-rative Model Validation

Experimental data is often stored in various file for-mats and unfortunately requires highly-specialized codesto parse each individual set of data. The lack of a struc-tured format makes it challenging to find relevant dataacross a diverse collection for model validation and un-certainty quantification (V/UQ). PrIMes open and flexi-ble data models provide needed structure to experimentaldata by using the XML file format. Every data value isdistinctly labeled, making it simple to search for and makeuse of data from several sources through a single searchquery. Recent additions of thousands of coal devolatiliza-tion and oxidation experiments highlighted the flexibilityof the PrIMe data models, enabling scientists to quicklyincorporate validation data from different sources in theirV/UQ analysis. A newly developed PrIMe app furtherallows for easy searching, visualization, and extraction oflarge amounts of data. We will present a working caseutilizing the app along with the coal data warehouse toquickly identify data sets relevant to a specific char oxida-tion model V/UQ study.

James OrelukUniversity of California [email protected]

MS5

Furnace Design: Extrapolation of Uncertainty

The objective of numerical combustion is to predict com-bustion quantities of interest in the absence of measuredresults. The accompanying uncertainty of the model pre-diction comes from a body of experimental evidence ob-tained at different scales. The model predictivity is thus anextrapolated (or in some cases interpolated) uncertainty.Traditionally, this extrapolation has been achieved througha hierarchical validation process. The hierarchy is tra-versed from the bottom up, to obtain the uncertainty forthe predicted quantity of interest at the top of the hier-archy. We present a top down uncertainty quantificationprocess that identifies the amount of bias error in all threecontributing aspects of the modeling process: model formuncertainty, numerical bias error, and simulation scenariouncertainty. The accuracy required of the modeled quan-tity of interest is defined by the objectives of the mod-eling exercise and defines the degree of modeling that is’good enough’. We demonstrate this process with the de-sign optimization of a new generation ultra-super-criticalpulverized-coal fired utility boiler using LES simulations

82 NC17 Abstracts

on 260,000 cores.

Philip J. SmithUniversity of [email protected]

Sean SmithThe University of [email protected]

MS6

Modeling, Simulation and Validation of an Ad-vanced Oxyfuel Combustor

For the development of new coal combustion technologiesadvanced methods and tools are needed. In this work ex-periments and numerical simulations are combined to in-vestigate and understand the underlying physico-chemicalprocesses of coal flames under oxyfuel conditions. A newtest-rig is presented bridging the gap between investiga-tions of open gas-assisted lab-scale flames and enclosed self-sustained coal flames. It is designed as a complementaryexperiment to an existing combustor for self-sustained coalcombustion. It retains all important geometrical featuresof the state-of-the-art coal burner designed for oxyfuel con-ditions while providing large optical access for detailed spa-tially and temporally resolved measurements using laser di-agnostics. The test-rig is optimized to provide well-definedand well-controlled boundary conditions. To validate andimprove existing models the investigation starts with thenon-reacting flow and increases complexity stepwise. Firstlarge eddy simulations (LES) of the non-reacting flow fieldare presented together with a quality assessment. TheLES results were compared to the flow field measured bystereoscopic particle image velocimetry and residence timedistributions captured by concentration measurements ofa tracer using laser absorption spectroscopy. The LESmethodology captured the flow and residence time distri-bution in an accurate manner which allows its further ex-tension to reacting conditions.

Samim DoostFG Energie- und KraftwerkstechnikTU [email protected]

Florian RiesEKTTU [email protected]

Robert KnappsteinFG Energie- und KraftwerkstechnikTU [email protected]

Francesca di MareInstitute for Energy and Powerplant TechnologyDarmstadt [email protected]

Amsini SadikiDepartment of Energy and Power Plant Technology,[email protected]

Johannes JanickaInstitute for Energy and Powerplant TechnologyDarmstadt University of Technology, Germany

[email protected]

Lukas BeckerRSMTU [email protected]

Sebastian [email protected]

Diego ZabrodiecInstitute of Heat and Mass TransferRWTH Aachen University [email protected]

Steven WagnerRSMTU [email protected]

Benjamin BoehmFG Energie- und KraftwerkstechnikTU [email protected]

Andreas DreizlerRSM, TU [email protected]

Reinhold KneerInstitute of Heat and Mass TransferRWTH Aachen University [email protected]

MS6

Biomass Pyrolysis in a Micro-Fluidized Bed: ACombined Experimental and Modeling Study

Thermochemical conversion of biomass has recently gaineda lot of interest as a potential renewable technology toprovide both liquid and gaseous fuels from a variety offeedstock, and much progress has been made in advanc-ing both experimental and modeling capabilities. How-ever, efficiently leveraging experimental measurements tovalidate and subsequently improve numerical simulationsof the relevant reactive gas-solid flow systems remains anoutstanding challenge, due to the sheer complexity of theconversion process itself, but also due to the lack of bestpractices in characterizing the reactors operating condi-tions and post-processing experimental measurements, of-ten qualitative in nature, specifically for comparisons withsimulation results. In order to gain direct and practical in-sight on how to best overcome this challenge, we considerthe joint experimental and numerical study of biomass py-rolysis in a micro-fluidized bed reactor (MFBR). Detailed,time-dependent characterization of the gas phase, includ-ing permanent gases and some primary tars, is obtainedexperimentally from GC and single photoionization (SPI)monitoring. Both detailed Lagrange-Euler and simplerone-dimensional approaches are used to simulate the re-actor. In this talk, we will discuss practical avenues toexploit the resulting extensive data sets for numerical vali-dation purposes, and the lessons we learned in establishinga valuable feedback loop for model improvement.

Perrine Pepiot, Himanshu Goyal

NC17 Abstracts 83

Cornell [email protected], [email protected]

Guillain Mauviel, Anthony Dufour, Liangyuan JiaLRGPUniversite de [email protected], [email protected], [email protected]

MS6

Solid Fuel Jet Flame Experiments and Simulations

Measurements on a combustion field by means of opticaldiagnostics techniques in addition to conventional contacttype measurements have recently become of major interestas tools for validating numerical simulations as well as clar-ifying the combustion mechanism. In this study, detailedmeasurements on a pulverized coal combustion coaxial pi-loted jet flame are conducted to investigate the combus-tion behavior. The flow field, the particle dispersion andthe flame structure, especially the physics in the ignitionprocess, are discussed in detail with the measured data byshadow Doppler particle analyzer (SDPA), multicolor in-tegrated receiving opitcs (MICRO), a two-color radiationpyrometer, OH and PAH planar laser induced fluorescence(OH- and PAH-PLIF), Mie scattering and time-resolvedlaser induced incandescence (Tire-LII). The effect of pilotflame is also discussed. A large-eddy simulation on thisjet flame was also performed to demonstrate the capabilityof the numerical simulation. The simulation results wereassessed with comparison to the measured data in terms ofsubmodels’ capability, such as models for devolatilization,char combustion and gaseous phase reactions. Finally, astrategy of further model validation for a pulverized coalcombustion from the experiment is discussed.

Hiroaki WatanabeDepartment of Mechanical EngineeringKyushu [email protected]

Kazuki TainakaEnergy Engineering Research LaboratoryCentral Research Institute of Electric Power [email protected]

MS6

1-D Flame Configuration for Validating PulverizedCoal Devolatilization and Oxidation Modeling

Joined experimental and numerical studies of devolatiliza-tion and oxidation of pulverized coal particles are con-ducted. The target configuration is a laminar axisymmet-ric methane/air strained-flow burner fed by coal particles.The flame is impinging a wall surface to enhance stabiliza-tion. Coal particles reactions take place in the hot region ofthe methane/air mixture. Visualization of OH*, CH* andC2* chemiluminescence, Laser Induced Fluorescence mea-surements of OH radical and flame emission spectroscopyare performed to identify the chemical flame structure andspecies concentration. The inlet fresh gas boundary con-ditions are well characterized in the experiments in termsof gas velocity but also number of coal particles and meanparticle diameter. Numerical investigations are performed,where the governing equations are fully coupled betweengas and particle phase. Detailed kinetic mechanisms, NOxchemistry and OH*/CH*/C2* sub-mechanisms are consid-ered for gas-phase kinetics. Coal devolatilization submod-

els are challenged on this configuration for describing par-ticle conversion. The analysis of obtained results confirmthat the presence of heavier hydrocarbons released by coalpyrolysis has a significant influence on the CH* and C2*concentration in the post-flame region. Finally, the effectsof volatile matter composition, strain rate and particle sizeon pollutant formation are studied.

Meng XiaEM2C laboratory, [email protected]

Philippe ScouflaireLaboratoire EM2C, Centrale [email protected]



MS7

Chemical Model Reduction Under Uncertainty

We outline a strategy for chemical kinetic model reductionunder uncertainty. We present highlights of our existingdeterministic model reduction strategy, and describe theextension of the formulation to include parametric uncer-tainty in the detailed mechanism. We discuss the utility ofthis construction, as applied to hydrocarbon fuel-air kinet-ics, and the associated use of probabilistic error measuresbetween predictions from detailed and simplified models.

Habib N. NajmSandia National LaboratoriesLivermore, CA, [email protected]

Mauro ValoraniDept. Meccanica e AeronauticaUniv. Rome La [email protected]

Riccardo Malpica GalassiDept. of Mechanical and Aerospace EngineeringUniv. Rome La [email protected]

MS7

Quantifying Variability in Sub-Models for LES ofReacting Flows

The multiphysics, multiscale nature of turbulent reactingflows makes these systems one of the most challenging tounderstand. Highly nonlinear fluid dynamic, thermody-namic, transport, chemical, and multiphase processes areintrinsically coupled and must be considered simultane-ously to satisfy the governing equations. The nonlinearnature of the system limits the number of assumptionsthat can be made without introducing significant errors.Conversely, significant assumptions must be made to de-rive multiscale closures that are both accurate and afford-able. To find an optimal balance, variability of individualsub-models and their coupled performance must be quan-

84 NC17 Abstracts

tified. In the current work, progress toward this goal ispresented in the context of Large Eddy Simulation (LES).Emphasis is on treatment of direct injection processes atDiesel engine conditions using the Sandia n-dodecane-airexperiments for validation. The extreme variability be-tween leading chemical mechanisms is highlighted. Thisvariability is accounted for using a novel model mechanismoptimized to reproduce autoignition delay times to withina specified tolerance. This is accomplished using Bayesianinference with a model-error representation. Error bars onthe predictions are obtained by quantifying the impact ofparameter uncertainties. Results are validated using ex-perimental data, then analyzed to gain further insights onpotential sources of error and variability in the flow.


Guilhem Lacaze, Layal HakimSandia National [email protected], [email protected]

MS7

Black Swans, Dragon Kings and the Science of RareEvents in Turbulent Combustion

The focus here is on anomalous behavior of systems underotherwise nominal operating conditions. Such events oc-cur due to the indeterminacy of a complex chaotic systemgiven a set of macroscopic operating parameters. Here, wepropose a dynamical systems approach to studying rareevents. In particular, we are interested in the formalismthat allows for such events to be simulated. This talk willcover the classification of rare events, and provide prelim-inary analysis using canonical configurations. The com-putational tools necessary for such risk prediction will bediscussed in the context of propagation algorithms used foruncertainty quantification.


Malik HassanalyDepartment of Aerospace EngineeringUniversity of [email protected]

MS7

Development of An UQ-Predictive Chemical Reac-tion Model for Syngas Combustion

An automated data-centric infrastructure, Process Infor-matics Model (PrIMe), was applied for validation and op-timization of a syngas combustion model. The Bound-to-Bound Data Collaboration (B2B-DC) module of PrIMewas employed to discover the limits of parameter modi-fications based on the systematic uncertainty and consis-tency analysis of the model-data system, with experimentaldata including shock-tube ignition delay times and laminarflame speeds. The initial H2/CO reaction model, assem-bled from 73 reactions and 17 species, was subjected toa B2B-DC analysis. For this purpose, a dataset was con-structed that included a total of 167 experimental targetsand 55 active model parameters. Consistency analysis ofthe composed dataset revealed disagreement between mod-els and data. Further analysis suggested that removing

45 experimental targets, 8 of which were self-inconsistent,would lead to a consistent dataset. This dataset was sub-jected to a correlation analysis, which highlights possibledirections for parameter modification and model improve-ment. Additionally, several methods of parameter opti-mization were applied, some of them unique to the B2B-DCframework. The optimized models demonstrated improvedagreement with experiment, as compared to the initially-assembled model, and their predictions for experiments notincluded in the initial dataset (i.e. a blind prediction) wereinvestigated.

Nadja SlavinskayaDLR Stuttgart [email protected]

Mehdi AbbasiGerman Aerospace Center(DLR), Institute ofCombustion Tech.70569, Stuttgart, [email protected]

Jan Hendrik Starcke, Aziza MirzayevaGerman Aerospace Center (DLR), Institute ofCombustion Tech70569, Stuttgart, [email protected], [email protected]

Wenyu Li, James Oreluk, Arun HegdeUniversity of California [email protected], [email protected],[email protected]

Andrew PackardU of California at [email protected]

Michael FrenklachUniversity of California at [email protected]

G. Gerasimov, O ShatalovInstitute of Mechanics, M. V. Lomonosov Moscow State U1 prosp. Michurinskii, Moscow, 119192, [email protected], [email protected]

MS8

Dns of Turbulent Lean Methane-Air Piloted JetFlames at High Karlovitz Number

DNS of a high Karlovitz number lean methane/air pilotedpremixed round jet flame is performed to understand theflame structure and propagation response to intense shear-driven turbulence. A reduced chemical model is incor-porated in the DNS with 28 species based on GRI-Mech3.0 including NO chemistry. The flame is in the broken-reaction zones regime and the preheat, inner reaction andoxidation layers are affected by turbulent strain and mix-ing. In the present study a multi-scale decomposition ofturbulent stretch rate and scalar dissipation rate will bepresented highlighting the effects of large- and small-scaleturbulent mixing and stretch on the flame structure andwrinkling. Multi-scale statistics will be presented at dif-ferent locations in the flame brush and at different axiallocations in the jet.

Haiou WangUniversity New South [email protected]

NC17 Abstracts 85

Evatt R. HawkesUniversity of New South [email protected]



MS8

Turbulence-Flame Interactions in High-Speed Pre-mixed Reacting Flows

The interaction between a premixed flame and the turbu-lence in which it propagates is a fundamental problem incombustion theory. The ability to describe these interac-tions both qualitatively and quantitatively is required forpractical problems ranging from the design of clean andefficient combustion engines to the development of next-generation scramjet propulsion. Turbulence-flame interac-tions are also central to astrophysical problems, such asexplosions of type Ia supernovae. In all of these contexts,turbulent fluid velocities can be large such that fluid mix-ing, even at the scale of the flame, is substantially largerthan characteristic heat release or chemical time scales, re-sulting in Karlovitz (Ka) numbers of order 102 or more.For such high Ka reacting flows, there can be substan-tial changes to the flame structure and burning rate. Inthis talk, we use direct numerical simulations (DNS) toexplore these changes for different values of Ka and fordifferent fuels. Changes in flame structure, burning rate,and chemical species evolutions are examined using bothEulerian and Lagrangian analysis approaches, and the ef-fects of premixed flames on the dynamics of the vorticity,turbulence intermittency, and kinetic energy spectral dy-namics are presented. The implications of these results formodeling of turbulent combustion are discussed.

Peter HamlingtonUniversity of Colorado, [email protected]

Alexei PoludnenkoTexas A&M [email protected]

MS8

Distributions of Flow Topology and Enstrophyin Different Turbulent Premixed CombustionRegimes: A Direct Numerical Simulation Investi-gation

Three-dimensional direct numerical simulation (DNS) datacontaining freely propagating statistically planar H2-airflames at three different Karlovitz number conditionswere analysed in order to investigate the distribution offlow topologies at different turbulent premixed combustionregimes. The flow topologies were characterized in termsof three invariants of velocity gradient tensor, namely P, Qand R, representing the negative of dilatation rate, strainrate, and enstrophy, respectively. The flow topologies werefurther categorized in eight types, i.e. S1-S8, dependingon the location of velocity gradient tensor in P-Q-R space.It was found that the weakening of dilatation rate with in-

creasing Karlovitz number plays a key role in flow topologyand enstrophy distribution in turbulent premixed flames.The contributions to enstrophy transport conditional ontopology were analysed in detail and it was found thatthe enstrophy generation mechanism due to the baroclinictorque weakens as the conditions move from the corrugatedflamelets to the broken reaction zone regime.

Hong G. ImKing Abdullah University of Science and [email protected]

Bill Papapostolou, Daniel WacksNewcastle [email protected],[email protected]

Markus KleinTechnische Universitaet DarmstadtInstitut fuer Energie und Kraftwerkstechnik, [email protected]

Nilanjan ChakrabortyNewcastle [email protected]

MS8

High Karlovitz Turbulent Flames: Is-This Only aLaboratory/DNS Toy Problem?

High Karlovitz number flames have been discussed atmany places in the literature in the context of Borghiregime diagrams. Along these lines, the amplitude of theKarlovitz numbers expected in various combustion systemsis first discussed. Then, the regime of high Karlovitz pre-mixed and non-premixed piloted flames is investigated us-ing micro-mixing modelling coupled with complex chem-istry. From the results, it is attempted to calibrate theflux of energy flowing from the burnt gases to the reac-tion zones in order to maintain high Karlovitz combustion.Conclusions are drawn concerning the generic character ofsuch flames.


MS9

Sparse Resolutions to Inconsistent Datasets ViaL1-Minimization

Bound-to-Bound Data Collaboration (B2BDC) provides anatural framework for addressing both forward and inverseuncertainty quantification problems. In this approach,parameter-to-QOI (quantity of interest) models are con-strained by experimental observations with interval uncer-tainty. A collection of such models and observations istermed a dataset and carves out a feasible region in theparameter space, which is representative of the currentstate of knowledge. Consistency analysis, a key attribute ofB2BDC, seeks to characterize this feasible set. If a datasethas a nonempty feasible set, it is consistent. In real-worldapplication, however, it is often the case that collections ofexperiments and observations are inconsistent. Revealingthe source of this inconsistency, i.e., identifying which mod-els and/or observations are problematic, is essential beforea dataset can be used for further analysis, such as predic-tion and optimization. In this presentation, we introducea constraint relaxation-based approach, entitled the vector

86 NC17 Abstracts

consistency measure, for investigating datasets with nu-merous sources of inconsistency. This new measure seeksa sparse set of relaxations by minimizing an L1-penalty.The benefits of vector consistency over previous methodsof consistency analysis are demonstrated in two realisticgas combustion examples.

Arun HegdeUniversity of California [email protected]

MS9

Uncertainties in Theoretical Chemical Kinetics

Theoretical chemical kinetics is increasingly being reliedon to provide input data for combustion modeling. As aresult, an improved understanding of their uncertainty isof increasing importance. Proper descriptions of the un-certainty in theoretical predictions are plagued by vari-ous factors including (i) correlations in the errors acrossthe components of the theoretical calculations, (ii) uncer-tainties in the reference data used to evaluate them, (iii)correlations across different theoretical methods, and (iv)a poor understanding of the uncertainties of some com-ponents of the calculation. We will explore these issuesthrough illustrative comparisons of theoretical calculationsof enthalpies and thermal rate constants with experimentaldata and with other theoretical calculations.

Stephen KlippensteinArgonne National [email protected]

MS9

Uniform Sampling of Feasible Set: A HybridStatistical-Deterministic Method of UncertaintyQuantification

Uncertainty quantification is key to developing predictiveand reliable combustion models. The Bound-to-BoundData Collaboration (B2BDC) framework defines a feasi-ble set of model parameters by constraining models withexperimental data. Posterior uncertainty information canbe explored by statistical analysis of the feasible set. Thispresentation extends the B2BDC framework by adding theability to generate uniform samples of the feasible set.Two rejection sampling methods were investigated withboth toy and realistic combustion datasets (GRI-Mechand DLR-SynG). We additionally developed two heuristicmethods for high-dimensional problems. The efficiency-accuracy trade-off was compared numerically. Posteriorcorrelations of GRI-Mech and DLR-SynG datasets wereobserved and will be discussed and interpreted.

Wenyu LiUniversity of California [email protected]

MS9

Automatic Chemical Mechanism Generation usingOptimized Rate Rules

Branched alkane species are essential constituents inpetroleum transportation fuels. A deep understanding oftheir oxidation performance contributes to efficient fuelconsumption and reduced pollutant formation in combus-tion devices. However, this becomes possible only after thesuccessful generation of accurate chemical kinetic models.

While the majority of available models still needs refine-ment, new chemical schemes are still missing for a largenumber of important fuels. A rapid and systematic de-velopment of accurate chemical mechanisms for branchedalkanes is thus of great interest. Recent studies have shownthat consistently updating thermochemistry and reactionpathways while optimizing rate rules for a set of C7-C11normal alkanes can be further applied to develop accuratechemical kinetic models for larger n-alkanes. This strategy,and its prior knowledge, are adopted in the present studyand further extended to develop optimized rate rules forbranched alkanes. The approach is also combined with anautomatic model development method to facilitate rapidgeneration of accurate chemical models for larger normaland branched alkanes without specific tuning of rate pa-rameters. It is shown that the models developed using thisstreamlined approach show very good agreement with ex-perimental data.


Liming CaiInstitute for Combustion Technology, RWTH [email protected]

MS10

Controlling Parameters in High Karlovitz NumberFlames: Small Scales, Large Scales, and Universal-ity

Turbulent premixed flames are characterized by numerousnon-dimensional numbers, including Reynolds, Karlovitz,and Damkhler numbers. Their respective impact on thetwo-way coupling between turbulence and chemistry hasbeen the subject of several studies already. In this pre-sentation, we will review past results and analyze recentresults from Direct Numerical Simulations of various hy-drocarbon/air flames. The analysis follows two directions.The first direction focuses on the characterization of the re-action zone surface (in terms of curvature, surface area...)and the evolution of the chemical source terms on thatsurface. The second focuses on the transformation ofturbulence across the flame and is investigated by con-sidering vorticity, its production, its dissipation, and its(an)isotropy. All results confirm that (for a given fuel/airmixture) the Karlovitz number controls entirely the smallscale chemical processes, not only the mean and the vari-ance, but also the full distribution of source term fluctua-tions. This conclusion remains valid regardless of the inte-gral length scale (equivalently the Reynolds number). Theevolution of the enstrophy is also strongly influenced by theKarlovitz number; yet, a small dependence on the Reynoldsnumber is observed. This is attributed to the lack of uni-versal behavior in finite Reynolds number flows.

Guillaume BlanquartCalifornia Institute of [email protected]

MS10

Low-Temperature Chemistry in Turbulent Pre-mixed Dodecane Flames

Turbulent lean premixed dodecane-air flames are simulatedin a doubly-periodic domain using detailed kinetics andtransport with a very recent kinetics model that features

NC17 Abstracts 87

improved descriptions of low-temperature chemistry. Inparticular, compared with previously published models,the new model shows dramatic shifts in the pyrolysis ofthe heavy fuel molecules occurring upstream of the primaryheat release zone. We explore the impact that turbulentmixing can play before it dissipates through the heat re-lease zone. For realistic values of Karlovitz and Damkohlernumber, we quantify the effects of the improved chemistrymodel with respect to earlier models.

Marc DayLawrence Berleley National [email protected]

Andrew [email protected]

John B. BellCCSELawrence Berkeley [email protected]

MS10

Transition of Combustion Mode During Flame-Flame Interaction and its Modeling Implication

Thermochemical conditions in various combustion deviceswill tend to be leaner, well-mixed, more diluted and dis-tributed using unconventional fuels. Such ”green” com-bustion technologies include syngas or biogas, ultra-lean,diluted and preheated combustion. Combustion of multi-component fuels produces thermo-diffusive instabilities,which increases local flame curvatures and surface area.Propagating flames under ultra-lean and/or diluted condi-tions have larger flame thickness and smaller flame speedcompared to a corresponding non-diluted stoichiometricflame, which yields small Damkohler and large Karlovitznumbers, enhancing convolution of flame surface. Flame–flame interactions are caused as a result of unsteady com-bustion process, and the occurrence becomes frequent whenflame surface fluctuation becomes relatively high for thereasons mentioned above. Several previous studies haveinvestigated flame–flame interactions in the context of for-mation of fresh reactants pockets. The heat release fluc-tuation resulted from the pocket formation is reportedlya source of combustion noise, and also could be importantfor prediction of pollutant formation. Thus, the underlyingphysics of flame interaction process needs to be understoodfor numerical modelling and to avoid these adverse effectswhen employing such combustion technologies.

Yuki MinamotoTokyo Institute of [email protected]

MS10

A Priori and a Posteriori Study of a High KarlovitzNumber Premixed Turbulent Jet Configuration

In this work, a data set of a Direct Numerical Simulation(DNS) of a turbulent CH4/air lean premixed jet flame con-figuration with high Karlovitz number (Ka = 250, basedon jet exit conditions) and detailed chemistry is studied.At these conditions, strong turbulence-chemistry interac-tions lead to large deviations from unperturbed combus-tion and conventional flamelet based combustion modelstend to fail. In an a priori analysis the optimal estima-tor concept, which allows for an error decomposition, is

applied to quantify errors of flamelet based combustionmodels. Furthermore, this concept is applied to iden-tify the quantities, which optimally parameterize interac-tions between turbulence and chemistry. These parametersare integrated into a priori formulations of flamelet com-bustion models to demonstrate the possible improvementsof flamelet based models in highly turbulent combustionregimes. Furthermore, a posteriori analysis of this config-uration is performed using Large-Eddy Simulations (LES)with two flamelet based combustion models. One is basedsolely on unstretched flamelet solutions, whereas the otherconsiders strained flamelet solutions. The latter shows im-proved agreement with the reference data from DNS andexperiment. The LES results and its errors are analyzedwith regard to further improvement of the flamelet basedmodels.

Konstantin KleinheinzInstitute for Combustion TechnologyRWTH Aachen [email protected]

L. BergerAachen [email protected]


Haiou WangUniversity New South [email protected]

Evatt R. HawkesUniversity of New South [email protected]


MS11

Prevention and Promotion of Flame Accelerationand Deflagration-to-Detonation Transition

Physical mechanisms of premixed flame acceleration (FA)due to (i) a finger shape, (ii) wall friction and (iii) in-builtobstacles are systematically investigated and compared inthe configurations of obstructed and unobstructed com-bustion tubes (CT). Specifically, the effects of mechanis-tic and thermal boundary conditions on FA; their inter-lay with thermal-chemical flame properties; and the pos-sibility to trigger a deflagration-to-detonation transition(DDT) event are quantified. The mechanistic conditionsinclude slip or non-slip walls, smooth or obstructed. Thethermal conditions include adiabatic or isothermal (cold orpreheated) walls. The thermal-chemical properties are cou-pled to the onset of the combustion instabilities. Namely,the Darrieus-Landau (DL) and diffusional-thermal (DT)instability modes are mainly described by the thermal ex-pansion factor and the Lewis number Le, respectively. It isshown that adiabatic walls and non-slip walls promote FA,which attains the exponential trend, and the effect is espe-cially strong in the case of obstructed CT. The same im-pact is provided by higher thermal expansions and for leannon-equidiffusive flames. In contrast, rich non-equidiffusiveflames propagate slower, as well as that with cold or pre-heated walls, where the exponential acceleration trend is

88 NC17 Abstracts

replaced by a liner one or even flame extinction. Based onthe combination of these effects, the promotive and pre-venting strategies for FA and DDT are provided.

V’yacheslav AkkermanDepartment of Mechanical and Aerospace EngineeringWest Virginia [email protected]

Orlando UgarteDepartment of Aerospace Engineering, University ofMarylandCollege Park, MD 20742, [email protected]

Serdar BilgiliWest Virginia [email protected]

Damir M. ValievCombustion Research FacilitySandia National [email protected]

MS11

Formation and Structure of Accelerating Combus-tion Wave

In the recent decades theoretical understanding of com-bustion phenomena, computational power and efficiency ofnumerical algorithms have grown tremendously. However,the long standing problem of Deflagration-to-DetonationTransition (DDT) is still beyond of quantitative predictionseven if modern physical models and numerical integrationpackages are used. Typically, in studies of the problem ofDDT an initial stage of the flame acceleration is somehowabsent and typically neglected from consideration. Thepresent talk aims to fill the gap and discusses this stage ofthe DDT. The study is motivated by recent experimentalevidences of so-called shockless transition to detonation ob-served in an obstructed channel where a flame propagatesfrom an open end to the closed one. The frame of 1D flatdeflagration of the hydrogen/oxygen and hydrogen/air sys-tems is employed. We use a very complex model of chem-ical kinetics and detailed descriptions of molecular diffu-sion for multi-component mixtures at elevated and variablepressure. In spite of 1D formulation it makes the problemof the flame acceleration a very challenging and demandingfor numerical treatments task. In the suggested talk exper-imental evidences and results of numerical experiments willbe represented and discussed.

Viatcheslav Bykov, Andrey koksharov

Karlsruhe Institute of Technology (KIT)[email protected], [email protected]

MS11

Turbulence Effects on Detonation Propagation andStructure

Comparative studies of turbulent inflow vertical and en-tropic forcing effects on the three dimensional detonationpropagation are conducted via direct numerical simula-tions based on Navier-Stokes equations and global one-stepchemical reaction model. The turbulent vertical and en-tropic forcing effects on the three dimensional detonationwave structures and front dynamics are analyzed, as wellas the detonation effects on turbulent vortex structures.

The turbulence field imposed has created small scale wrin-kles embedded in the detonation front, apart from the largescale features of detonation without turbulence. The det-onation propagating velocity varies from 0.8 to 1.6 CJ ve-locity and its pdf skewes to sub-CJ velocity and peaks atabout 0.9. The detonation velocity recorded with time al-ways preferentially decays, with very rapid accelerationsthrough triple point interactions. Its pdf also skews tosub-CJ velocity, while its overall shape agrees well withV-3. The reaction zone is greatly influenced by the vor-tex, much more irregular and turbulent and elongated forthe turbulent cases. Distributed burning pockets are morelikely to be found there. The turbulent kinetic energy isamplified across the detonation, and periodically oscillatedownstream the detonation due to the periodically colli-sion of the triple points. Finally, the Favre averaged meanstructure of the detonation waves and comparisons withthe analytical ZND structure are discussed in detail.

Kun Luo, Tai Jin, Jianren FanZhejiang [email protected], [email protected], [email protected]

MS11

Flame Acceleration in Long Narrow Channels En-hanced by Compressibility Effects

The effects of gas compressibility on the propagation ofpremixed flames in narrow channels closed at their igni-tion end have been studied, under adiabatic conditionsand in the presence of controlled heat losses. Earlier workhas shown that, in sufficiently long adiabatic channels,the flame evolves into a steadily propagating compression-driven flame. The propagation speed of these flames de-pends exponentially on the constant-volume equilibriumtemperature, and is therefore significantly larger than or-dinary isobaric flames. In the present work, we show thatheat losses control the transition between the slow isobaricand the fast compression-driven flames.

Vadim KurdyumovCIEMAT, [email protected]

Moshe MatalonUnivesity of Illinois at [email protected]

MS12

Interfacial and Bulk Thermodynamics in Supercrit-ical Combustion

The thermodynamics of high pressure mixing and combus-tion are still not well understood. While the change of jetdisintegration from liquid jet break-up to a turbulent mix-ing process at supercritical pressures is well documented,the state of knowledge about the thermodynamic structureof non-premixed flames at supercritical pressure is still in-complete. Previous studies have mainly focused on thephase behavior of inert hydrogen - oxygen mixtures. How-ever, in 1D and LES studies of non-premixed flames, wedid not observe such large scale inert real fluid mixing. In-stead, under rocket engine conditions, an attached flameseparates fuel and oxidizer; the cryogenic oxygen streamundergoes a supercritical liquid to real gas transition -pseudoboiling - before mixing with reaction products. Onlytraces of water (Y¡0.03) are present in the cryogenic oxy-gen stream before the mixture transitions to an ideal gasstate. While state-of-the-art real fluid CFD mixing rules

NC17 Abstracts 89

based on the extended corresponding states principle pre-dict a single phase flow, vapor-liquid-equilibrium calcula-tions instead show that the water will condense as it dif-fuses towards the oxygen, even when the oxygen injectiontemperature is raised to 300 K. As the opening talk of themini-symposium, we will provide links to the following pre-sentations by emphasizing certain aspects of supercriticalcombustion modeling, such as the steep density gradients,phase separation, and supercritical fluid properties.


Peter C. Ma, Muralikrishna RajuStanford [email protected], [email protected]


MS12

Thermodynamic, Dynamic and Structural Proper-ties of Compressed Liquids and Supercritical Fluids

While scientists have a good theoretical understanding ofthe heat capacity of both solids and gases, a general theoryof the heat capacity of liquids has always remained elusive.I will introduce a phonon-based approach to liquids and su-percritical fluids to describe its thermodynamics in termsof sound propagation. I will show that the internal liquidenergy has a transverse sound propagation gaps and ex-plain their evolution with temperature variations on theP-T diagram. As a result, the experimental evidence forthe new thermodynamic boundary in the supercritical state(the Frenkel line) on the P-T phase diagram will be demon-strated. Then, I will report on inelastic X-ray scatteringand diffraction experiments combined with the moleculardynamics simulations on supercritical Ar. The presentedresults unveil the mechanism and regimes of sound prop-agation in supercritical fluids providing a compelling ev-idence for the adiabatic-to-isothermal longitudinal soundpropagation transition. As a result, a universal link will bedemonstrated between the positive sound dispersion phe-nomenon and the origin of transverse sound propagationrevealing the viscous-to-elastic crossover. Both can be con-sidered as a universal fingerprint of the dynamic response ofa liquid. They can be used then for a signal detection andanalysis of a dynamic response in deep water and other flu-ids which are relevant for describing their thermodynamics.The consequences of this finding will be discussed.

Dima BolmatovBrookhaven National [email protected]

MS12

Analytical / Computational Approach to Liquid In-jection at Supercritical Pressures

Our findings from three areas of background research willdefine an approach to the study of liquid injection intogases at supercritical pressure: vaporizing droplets at su-percritical pressure, vorticity dynamics of incompressibleliquid jets flowing into gas, and supercritical combustion insimple configurations, e.g., counterflow. It will be shown

that vorticity dynamics analysis is essential to explain thephysical mechanisms; surface dynamics alone tells little.Liquid-jet atomization is the result of a transitional tur-bulence where, in sequence, smaller and smaller scales areformed driven by the behavior of hairpin vortices. At thecascade end, capillary action forms droplets. Several dif-ferent cascade processes are identifiable depending on theReynolds and Weber numbers and the density ratio be-tween the liquid and the ambient gas. Even if one phaseexists in extreme cases, these hairpin-vortices mechanismswill be controlling in forming discrete blobs of the injectedmaterial. The a priori conclusion that one phase exists atsupercritical pressure is based on false lore and not physicallaw. The question about the phases must be left open untilthe analysis reaches a conclusion; a proper approach willbe defined. Proper equations of state for density and en-thalpy and the determination of phase equilibrium, liquidcomposition due to dissolved gas, energy of vaporization,surface tension, and transport properties for high pressureswill be discussed.

William SirignanoUniversity of California, [email protected]

MS12

Modeling of High Pressure Sprays and CombustionBased on Phase Equilibrium and Jet Theory withThermal Radiation

A new CFD spray model has been developed for IC en-gine simulations that is based on the assumption of localphase equilibrium and jet theory. Phase equilibrium is de-termined by an advanced solver that is based on rigorousthermodynamics with Peng-Robinson Equation of State.Jet theory is applied for the sub-grid mixing-controlledprocess and particle-gas momentum exchange, to relax themodel grid dependency. The model provides good predic-tions of spray mixture preparation, and the combustionprocess is accurately predicted without the need to resolvethe jet breakup process. Thermal radiation is also includedin the modeling. The influence of radiation on steady stateflame temperature and soot formation for the ECN SprayA was studied and was found to be negligible. In this casethe contribution of soot to total thermal radiation is smalldue to its relatively small amount and low temperature,compared to the absorbing gas. However, engine simula-tions show that thermal radiation can have a significantimpact on transient soot formation, and non-linear effectsare found for post-injection cases.

Zongyu YueUniversity of Wisconsin - [email protected]

Rolf ReitzUniversity of [email protected]

MS13

Analytical and Computational Description of aCoalmine Fire Scenario

Every year, worldwide, explosive accidents claim numer-ous lives of workers and customers in industries dealingwith combustible gases, dust and other explosive materi-als. Among these industries, historically, coalmining hasone of the highest fatality and injury rates. To reducethe risk of explosions in coalmines, a fundamental physi-

90 NC17 Abstracts

cal understanding of the coal dust / methane / air com-bustion processes is critically needed. The present work,combining comprehensive analytical endeavors and compu-tational simulations, is a step in this direction. First, toreveal the inner mechanisms of a combustion accident ina coalmine, the key stages and characteristics of premixedflame evolution in a mining passage such as the propaga-tion speeds, acceleration rates and run-up distances arescrutinized, through the analytical studies, in large-scalemining passages. The study is mainly focused on the flameacceleration scenarios due to a finger flame shape and wallfriction. It is for the first time that the spatial distributionsof the combustion characteristics such as the unstretchedlaminar burning velocity are incorporated in the analysis.Subsequently, the formulations are revisited by incorpo-rating the effect of compressibility. Additionally, a com-putational platform is developed to validate the analyticalpredictions and model the nonhomogeneous distribution ofcoal dust particles in coalmining passages.

Sinan DemirWest Virginia [email protected]

Hayri Sezer, Ali S. RangwalaWorcester Polytechnic [email protected], [email protected]


MS13

Formation and Structure of Quasi-DetonationOblique Reaction Front in Annular Channel

Strong promoting effect of annular channel geometry onflame acceleration and DDT was recently found. The flamearea at the bend part increases several times without anyimpact of turbulence. A series of experiments on premixedburning in annular channels of thickness 1-, 3-, 5-cm andouter dimeter 28 cm is performed. The test channel wasfilled with 15-85% H2/O2 premixtures at normal pressureand temperature, and then ignited near the outer wall. Ini-tially spherical, a then-oblique reaction front propagatesalong the outer wall. Different inner and outer channelcurvature provides additional flame stretching, which leadsto a drastic increase in the flame surface and rapid ac-celeration to a near-sonic (350-650m/s) speed. For mostreactive mixtures (40-80% H2), the tangential flame veloc-ity reaches the Chapman-Jouguet (CJ) detonation velocity(2100-3400m/s). The complex formed by an oblique shockwave and a subsonic deflagration in an annular channel isanalytically investigated. The ensemble has the notableproperty to propagate with the CJ velocity in the circum-ferential direction being of intrinsic subsonic nature. Thestructure is discussed in detail utilizing an algebraic ap-proach yielding an insight of apparently contradictory ex-perimental observations of a deflagration which propagateswith CJ velocity. The nature of the complex is qualita-tively presented, and the mathematical relations governingthe states of the gas in different areas of the ensemble arederived.

Mike Kuznetsov, Jorge YanezKarlsruhe Institute of Technology (KIT)

[email protected], [email protected]

MS13

Diffusion Flames and Diffusion Flame-Streets inThree Dimensional Micro-Channels

Experiments of nonpremixed combustion in microchan-nels exhibit different burning modes. Typically, a diffu-sion flame is established along/near the channel axis span-ning the entire mixing layer, separating the fuel/oxidizerregions. Often, however, a periodic sequence of extinc-tion and reignition events, termed collectively as diffusionflame-streets, is observed, with a series of separate diffu-sion flames, each with a tribrachial edge-flame structurethat is stabilized along the channel. This work focuses onunderstanding the mechanism responsible for these uniqueobservations. Numerical simulations were conducted in athermo-diffusive limit to examine the effects of confinementand heat loss on flames in 3D microchannels with low as-pect ratios. An asymptotic analysis was used to reducethe problem into a 2D one, which effectively captured 3Dnature of combustion processes. Two key burning regimeswere identified: (i) stable continuous diffusion flames and(ii) stable diffusion flame-streets. The transition betweenthese regimes is demarcated primarily by the Damkohlernumber, defined as the diffusion-to-chemical times ratio,but is also influenced by the extent of heat loss. Occasion-ally within the diffusion flame-street regime, the residualmixture would reignite but fail to evolve into stationaryauxiliary flames. This was observed at low flowrates forsubcritical Re. The behavior is periodic in time, with afrequency dependent on the removal from criticality.

Shikhar Mohan, Moshe MatalonUnivesity of Illinois at [email protected], [email protected]

MS13

DDT in Channels with Tightly Spaced Obstacles

A qualitatively new mechanism of fast flame accelerationin channels with obstacles has been recently suggested [By-chkov et al., Phys. Rev. Lett. 101, 164501 (2008)]. Theadvantage of the mechanism is that it does not dependon the Reynolds number. Obstacles have been used fora long time in DDT experiments for making flame accel-eration stronger. It was a general belief that the Shelkinmechanism controls flame acceleration both in smooth andobstructed channels, and the main role of obstacles is tomake the gas flow turbulent. In contrast to this approach,Bychkov et al. have demonstrated that the tightly spacedobstacles provide a qualitatively new mechanism of fastflame acceleration, while the role of turbulence is only sup-plementary. The theoretical predictions were supported byextensive numerical simulations and comparison to avail-able experimental data. It was demonstrated that flameaccelerates in the most effective way for thin obstacles withrelatively small spacing in between them. Here we reviewthe latest developments in theory and simulations of flameacceleration and DDT in channels with tightly spaced ob-stacles. In particular, we focus on the effect of gas com-pression in axisymmetric geometry. Also, we study howthe obstacle length, distance between the obstacles, chan-nel width, and thermal boundary conditions at the outerwalls can modify flame propagation through a comb-shapedarray of parallel thin obstacles.

Damir M. ValievCombustion Research Facility

NC17 Abstracts 91

Sandia National [email protected]

Orlando UgarteDepartment of Aerospace Engineering, University ofMarylandCollege Park, MD 20742, [email protected]


MS14

Modelling of a Coaxial Lox/gh2 Injection Elementunder High Frequency Transverse Acoustic Veloc-ity Forcing

A specialized high frequency combustion instability experi-ment, designated BKH, has been conducted at the DLR In-stitute for Space Propulsion. The BKH experiments oper-ate with liquid oxygen and gaseous or liquid hydrogen pro-pellants at supercritical conditions analogous to real rocketengines. In the experiment the response of 5 coaxial ele-ments to imposed acoustic disturbances is observed via lineof sight optical access to the combustion zone. Analysis ofhigh speed optical data shows that the flames positionedin a pressure node are both transported by the acousticvelocity and shortened during excitation of the first trans-verse acoustic mode. A URANS model of a BKH injectionelement subjected to representative acoustic forcing hasbeen computed using a specialized release of the DLR TAUcode. This release includes a finite rate chemistry combus-tion model and a real gas capability for modelling cryogenicpropellant injection. The single injector model reproducesthe transverse transport and shortening of the flame ob-served experimentally. The model also provides additionalinsight into the deformation of the flame which could notbe observed experimentally. A range of excitation ampli-tudes were studied to compare with previously publishedexperimental results correlating flame length with acousticvelocity amplitude. The same trend observed experimen-tally was successfully reproduced by the numerical model.

Scott BeinkeGerman Aerospace Center (DLR)[email protected]


Justin HardiGerman Aerospace Center (DLR)[email protected]

Sebastian KarlGerman Aerospace [email protected]

Michael OschwaldGerman Aerospace Center (DLR)[email protected]

Bassam DallyThe University of AdelaideDepartment of Mechanical [email protected]

MS14

Experimental Test Ccases for Modelling Supercrit-ical Combustion in Rocket Engines

Due to their challenging nature, there are a limited numberof high quality experiments which can be used as test casesfor modelling supercritical combustion in liquid propellantrocket engines. The German Aerospace Center (DLR), In-stitute for Space Propulsion operates several experimentalrocket combustors with optical access which are able toprovide data useful for the validation of numerical mod-elling. Three such experiments running cryogenic oxygen-hydrogen propellants have recently been used to generatedata sets for this purpose. They range in scale from lowpower, single injector to high power, multi-injector config-urations representative of upper stage engines. Two of theexperiments are also used to study thermo-acoustic cou-pling phenomena relevant to combustion instabilities, in-troducing further aspects of complexity to the experimentsand the models. These test cases are currently being mod-elled both internally at the DLR and by external part-ners in the frame of modelling workshops. Through thecollaboration with modellers, the experimentalists are alsoaddressing the challenges in comparing results from differ-ent modelling approaches with experimental data. Recentlessons learned are leading to improved methodologies tobridge the divide between the two types of data and pro-vide better validation of the models.

Justin Hardi, Scott Beinke, Dmitry Suslov, MichaelOschwaldGerman Aerospace Center (DLR)[email protected], [email protected],[email protected], [email protected]

MS14

Robust Treatment of Thermodynamic Nonlineari-ties in the Simulation of Transcritical Flows

High-pressure flows are known to be challenging to simu-late due to thermodynamic nonlinearities occurring in thevicinity of the pseudo-boiling line. This study investigatesthe origin of this issue by analyzing the behavior of ther-modynamic processes at elevated pressure and low temper-ature. We show that under transcritical conditions, non-linearities significantly amplify numerical errors associatedwith construction of fluxes when a fully conservative ap-proach is employed. These errors generate pressure vari-ations that can be significant close to the pseudo-boilingline in thermodynamic space. For solvers based on a con-servative system of equations, these perturbations hindernumerical stability and degrade the accuracy of predictionsas non-physical turbulence may appear or unstable acousticmode triggered. To circumvent this problem, the governingsystem can be reformulated to a pressure-based treatmentof energy. This work presents comparisons between thepressure-based and fully conservative formulations usinga progressive set of canonical cases, including a cryogenicturbulent mixing layer at rocket engine conditions. Advan-tages and drawbacks are discussed and new ideas on howto simulate such flows are proposed.

Guilhem Lacaze, Anthony RuizSandia National Laboratories

92 NC17 Abstracts

[email protected], [email protected]



MS14

Diffuse Interface Transcritical Flames Models: AComparison

Diffuse interface models are extensively used in the field ofsubcritical combustion and allow the numerical representa-tion of phenomena occuring in the narrow dense-to-diluteinterface. This representation may be either direct thanksto models such as Van der Waals/Korteweg models or in-direct in the case of multifluids approaches. Continuousdescription of the interface ease computation of geometri-cally complex situation such as droplets fragmentation orligament breaking. Diffuse interface models retain theirrelevance under supercritical conditions when the smoothdense-to-dilute transition is narrowed through stretch, mo-tivating developpment of transcritical models. We per-form an a priori comparison between extended Van derWaals/Korteweg models (P. Gaillard, V. Giovangigli, andL. Matuszewski, A Transcritical Diffuse Interface H2/LOXflame model, Comb. Theory Mod. 20 (2016), pp. 486–520) and multifluids approaches in term of thermodynam-ics, flux and entropy production. Transcritical flame struc-tures obtained through these modellings are also comparedas well as numerical efficiency of these approaches.

Vincent GiovangigliCMAP, Ecole [email protected]

Lionel Matuszewski, Pierre [email protected], [email protected]


NC17 Speaker and Organizer Index


GGallot-Lavallée, Simon, CP4, 11:10 Mon

Gambino, James R., MS1, 2:00 Mon

Ghani, Abdulla, CP10, 4:10 Mon

Gierth, Sandro, CP3, 10:10 Mon

Givi, Peyman, IP3, 8:15 Wed

Goshayeshi, Babak, CP3, 10:50 Mon

Govindaraju, Pavan B., CP4, 10:10 Mon

Grana-Otero, Jose, CP18, 3:30 Tue

Grana-Otero, Jose, CP18, 5:10 Tue

Grenga, Temistocle, CP15, 2:20 Tue

Grogan, Kevin, CP11, 4:10 Mon

Grøvdal, Fredrik, CP24, 2:00 Wed

Guo, Ning, CP21, 9:30 Wed

Guven, Umut, CP6, 1:40 Mon

HHamlington, Peter, MS8, 2:00 Tue

Hansen, Michael A., CP3, 9:30 Mon

Harcombe, Geraint, MS3, 4:00 Mon

Hardi, Justin, MS14, 1:30 Wed

Hashimoto, Nozomu, CP23, 9:30 Wed

Hassanaly, Malik, CP26, 2:20 Wed

Hasse, Christian, MS6, 9:30 Tue

Hegde, Arun, MS9, 4:00 Tue

Huan, Xun, MS4, 3:30 Mon

IIavarone, Salvatore, CP21, 10:10 Wed

Ihme, Matthias, MS12, 9:30 Wed

Ihme, Matthias, MS14, 1:00 Wed

Im, Hong G., MS8, 1:00 Tue

Imren, Abdurrahman, CP9, 4:10 Mon

Ioannou, Eleftherios, MS1, 1:00 Mon

JJackson, Haran, MS3, 3:30 Mon

Jackson, Thomas, CP1, 9:50 Mon

Ji, Weiqi, CP16, 1:00 Tue

Johnson, Ryan F., CP9, 4:30 Mon

Ceranic, Nemanja, CP8, 2:00 Mon

Charchi Aghdam, Ali, CP2, 9:50 Mon

Chatelier, Adrien, CP7, 1:00 Mon

Chen, Jacqueline, MS8, 2:30 Tue

Chiquete, Carlos, CP1, 9:30 Mon

Chong, Shao Teng, CP8, 1:20 Mon

Cisneros-Garibay, Esteban, CP16, 2:40 Tue

Clayton, Parker, CP16, 2:00 Tue

Cunha Caldeira Mesquita, Leo, CP11, 3:50 Mon

Cuoci, Alberto, CP19, 3:30 Tue

DDavani, Ashkan, CP19, 4:10 Tue

Davani, Ashkan, CP24, 1:40 Wed

Davis, Michael J., MS5, 10:30 Tue

Day, Marc, MS10, 5:00 Tue

Demir, Sinan, MS13, 2:30 Wed

Denker, Dominik, CP12, 10:50 Tue

Doan, Nguyen Anh Khoa, CP2, 10:50 Mon

Domingo, Pascale, CP11, 4:30 Mon

Dunn, Dennis, CP4, 10:50 Mon

EEdoh, Ayaboe K., CP20, 4:30 Tue

Evrard, Fabien, CP4, 10:30 Mon

FFang, Jian, CP6, 2:40 Mon

Ferreira, Tatiele, CP3, 10:30 Mon

Fillo, Aaron J., CP13, 10:50 Tue

Franke, Lucas, CP3, 9:50 Mon

Franzelli, Benedetta G., CP8, 2:20 Mon

Frenklach, Michael, MS5, 9:30 Tue



Fürst, Magnus, CP13, 11:10 Tue

AAbdelgadir, Ahmed, CP8, 1:00 Mon

Ahmed, Umair, CP18, 3:50 Tue

Akkerman, V’yacheslav, MS11, 9:30 Wed



Alam, Fahd E., CP7, 2:20 Mon

Alexander, Raymond, CP8, 1:40 Mon

Alkahtani, Badr, CP12, 10:10 Tue

Armstrong, Elizabeth, CP6, 2:20 Mon

Aslam, Tariq D., MS3, 4:30 Mon

Attili, Antonio, CP22, 9:30 Wed

Aversano, Gianmarco, CP9, 3:30 Mon

BBanuti, Daniel, MS12, 9:30 Wed

Banuti, Daniel, MS12, 9:30 Wed

Banuti, Daniel, MS14, 1:00 Wed

Bauman, Paul, MS2, 2:00 Mon

Beinke, Scott, MS14, 2:00 Wed

Belhi, Memdouh, CP2, 9:30 Mon

Berger, Lukas, CP26, 1:40 Wed

Bilger, Camille, CP7, 2:40 Mon

Bioche, Kevin, CP10, 5:10 Mon

Blanquart, Guillaume, MS10, 4:00 Tue

Boehm, Benjamin, MS6, 10:30 Tue

Bolmatov, Dima, MS12, 10:00 Wed

Borghesi, Giulio, CP4, 9:30 Mon

Boulet, Lancelot, CP7, 1:20 Mon

Brandle De Motta, Jorge Cesar, CP7, 1:40 Mon

Burke, Michael P., MS5, 11:00 Tue

Buttay, Romain, CP22, 9:50 Wed

Bykov, Viatcheslav, MS11, 10:30 Wed

CCai, Jian, CP10, 3:30 Mon

Cailler, Mélody, CP13, 10:10 Tue

Capecelatro, Jesse, CP13, 10:30 Tue

Italicized names indicate session organizers


PPaixao de Almeida, Yuri, CP11, 3:30 Mon

Palluotto, Lorella, CP14, 9:50 Tue

Pantano, Carlos, IP1, 8:15 Mon

Paul, Chandan, CP10, 4:30 Mon

Pepiot, Perrine, IP2, 8:15 Tue

Pepiot, Perrine, MS6, 9:30 Tue

Pepiot, Perrine, MS6, 11:00 Tue

Perry, Bruce A., CP26, 2:00 Wed

Pisciuneri, Patrick, CP12, 11:10 Tue

Pitsch, Heinz, MS9, 3:30 Tue

Pitsch, Heinz, MS10, 4:30 Tue

Prosser, Robert, CP5, 10:10 Mon

RRaman, Venkat, MS7, 2:00 Tue

Ren, Ning, CP25, 1:40 Wed

Ribert, Guillaume, CP20, 3:30 Tue

Ricchiuti, Valentina, CP2, 10:10 Mon

Riedel, Uwe, CP13, 9:30 Tue

Rieth, Martin, CP14, 10:30 Tue

Rodrigues, Pedro, CP20, 4:10 Tue

Romick, Christopher, MS3, 5:00 Mon

Roy, Somesh P., CP21, 10:50 Wed

Ruan, Jiangheng, CP17, 1:00 Tue

SSahafzadeh, Meysam, CP5, 10:30 Mon

Salenbauch, Steffen, CP8, 2:40 Mon

Sankaran, Ramanan, CP11, 4:50 Mon

Santner, Jeffrey, CP23, 11:10 Wed

Scholtissek, Arne, CP3, 11:10 Mon

Schulz, Oliver, CP5, 11:10 Mon

Sewerin, Fabian, CP17, 2:00 Tue

Shaddix, Christopher, MS6, 9:30 Tue

Shields, Ben, CP12, 10:30 Tue

Short, Mark, CP1, 10:50 Mon

Matalon, Moshe, MS13, 2:00 Wed

Matuszewski, Lionel, MS14, 1:00 Wed

Mcconnell, Josh T., CP6, 1:20 Mon

Mehl, Cedric C., CP12, 9:50 Tue

Meraner, Christoph, CP26, 1:20 Wed

Mi, XiaoCheng, MS1, 2:30 Mon

Michael, Louisa, MS1, 1:00 Mon

Michael, Louisa, MS3, 3:30 Mon

Millán-Merino, Alejandro, CP16, 1:20 Tue

Minamoto, Yuki, MS10, 3:30 Tue

Minuzzi, Felipe C., CP16, 1:40 Tue

Mira, Daniel, CP25, 2:20 Wed

Mortada, Mohammad, CP14, 11:10 Tue

Moureau, Vincent R., CP20, 5:10 Tue

Mueller, Michael E., MS4, 4:00 Mon

Mueller, Michael E., CP15, 1:00 Tue

NNajm, Habib N., MS5, 9:30 Tue

Najm, Habib N., MS7, 1:00 Tue



Nave, Ophir, CP26, 1:00 Wed

Nayigizente, Davy, CP22, 11:10 Wed

Nemitallah, Medhat A., CP23, 9:50 Wed

Nez, Robin, CP23, 10:10 Wed

Niemeyer, Kyle E., CP16, 2:20 Tue

Niemeyer, Kyle E., CP19, 4:50 Tue

Nivarti, Girish, CP18, 4:10 Tue

Nivarti, Girish, CP24, 1:00 Wed

OO’Brien, Jeffrey D., CP14, 9:30 Tue

Oefelein, Joseph C., MS7, 1:30 Tue

Oliver, Todd A., MS2, 1:00 Mon



Oreluk, James, MS5, 10:00 Tue

KKempf, Andreas, MS6, 9:30 Tue

Khan, Salam, CP26, 2:40 Wed

Kiyanda, Charles B., CP5, 9:30 Mon

Klippenstein, Stephen, MS9, 4:30 Tue

Kolla, Hemanth, MS8, 1:00 Tue

Kolla, Hemanth, MS10, 3:30 Tue

Kolla, Hemanth, CP21, 11:10 Wed

Konduri, Aditya, CP22, 10:10 Wed

Koniavitis, Panayiotis, CP13, 9:50 Tue

Kramer, Boris, MS2, 1:00 Mon



Krisman, Alex, CP22, 10:30 Wed

Kronenburg, Andreas, MS6, 9:30 Tue

Kuznetsov, Mike, MS13, 1:30 Wed

LLabahn, Jeffrey, CP14, 10:10 Tue

Lacaze, Guilhem, MS14, 2:30 Wed

Lackmann, Tim, CP4, 9:50 Mon

Lancien, Thea, CP7, 2:00 Mon

Lapenna, Pasquale, CP5, 9:50 Mon

Lattimer, Alan, MS4, 4:30 Mon

Li, Tian, CP21, 9:50 Wed

Li, Wenyu, MS9, 5:00 Tue

Li, Zhiyi, CP14, 10:50 Tue

Liang, Jianhan, CP20, 4:50 Tue

Llor, Antoine, CP12, 9:30 Tue

Lu, Zhen, CP9, 5:10 Mon

Luca, Stefano, CP15, 1:20 Tue

Luo, Kun, MS11, 11:00 Wed

Lv, Yu, CP20, 3:50 Tue

MMa, Peter C., CP6, 2:00 Mon

Macart, Jonathan F., CP10, 3:50 Mon

Masselot, Damien, CP1, 10:10 Mon

Matalon, Moshe, MS11, 10:00 Wed



WWang, Hongbo, CP23, 10:50 Wed

Wang, Qing, CP17, 2:40 Tue

Watanabe, Hiroaki, MS6, 9:30 Tue

Watanabe, Hiroaki, MS6, 9:30 Tue

West, Richard, CP9, 3:50 Mon

Wick, Achim, CP21, 10:30 Wed

Wilkinson, Simon D., MS1, 1:30 Mon

Wu, Hao, CP19, 4:30 Tue

XXia, Meng, MS6, 10:00 Tue

Xie, Wenwen, CP19, 5:10 Tue

Xu, Xiao, CP24, 1:20 Wed

YYao, Jin, CP1, 10:30 Mon

Yue, Zongyu, MS12, 11:00 Wed

ZZaiger, Matthew F., CP2, 10:30 Mon

Zhang, Jian, CP15, 2:40 Tue

Zhao, Xinyu, MS8, 1:00 Tue

Zhao, Xinyu, CP17, 2:20 Tue

Zhao, Xinyu, MS10, 3:30 Tue

Zschutschke, Axel, CP18, 4:50 Tue

Sircar, Arpan, CP10, 4:50 Mon

Sirignano, William, MS12, 10:30 Wed

Slavinskaya, Nadja, MS7, 2:30 Tue

Smith, Philip J., MS5, 9:30 Tue




Sobhani, Sadaf, CP25, 2:00 Wed

Sondak, David, MS2, 1:00 Mon

Stein, Oliver T., MS6, 9:30 Tue

Stein, Oliver T., CP22, 10:50 Wed

Stewart, D. Scott, CP1, 11:10 Mon

Stoellinger, Michael, CP6, 1:00 Mon

Sui, Yang, CP24, 2:20 Wed

Sun, Mingbo, CP23, 10:30 Wed

TTang, Yihao, CP25, 2:40 Wed

Terashima, Hiroshi, CP19, 3:50 Tue

Trivedi, Shrey, CP18, 4:30 Tue

Tyliszczak, Artur, CP17, 1:20 Tue

VValiev, Damir M., MS13, 1:00 Wed

Valreau, Audrey, CP5, 10:50 Mon

Vervisch, Luc, MS8, 1:30 Tue

Vervisch, Luc, CP15, 2:00 Tue

Vicquelin, Ronan, CP25, 1:00 Wed

Vié, Aymeric, CP25, 1:20 Wed

Volpiani, Pedro S., CP17, 1:40 Tue

Volpiani, Pedro S., CP15, 1:40 Tue

Vp, Ramesh, CP9, 4:50 Mon



Conference Budget

April 3-5, 2017Orlando, FL

Expected Paid Attendance 185

RevenueRegistration Income $94,645

Total $94,645

ExpensesPrinting $1,100Organizing Committee $2,400Invited Speakers $4,100Food and Beverage $25,500AV Equipment and Telecommunication $10,800Advertising $3,300Conference Labor (including benefits) $24,771Other (supplies, staff travel, freight, misc.) $6,900Administrative $7,606Accounting/Distribution & Shipping $4,157Information Systems $7,644Customer Service $2,864Marketing $4,421Office Space (Building) $2,922Other SIAM Services $3,045

Total $111,530

Net Conference Expense -$16,885

Support Provided by SIAM $16,885$0

Estimated Support for Travel Awards not included above:

Students 14 $12,830

Sixteenth International Conference on Numerical Combustion (NC17)

NC17 Budget

Rosen Plaza HotelFloor Plan

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