core research on hydrogen safety and epsrc challenge project · core research on hydrogen safety...
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D. Makarov, V. Molkov
Hydrogen Safety Engineering and Research Centre, University of Ulster
Core research on hydrogen safety
and EPSRC Challenge project
“Integrated safety strategies for
onboard hydrogen storage system”
SUPERGEN HUB Research and Advisory Board meeting
Newcastle University, 30-31 July 2014
Core research
Work Package 3: Hydrogen and Fuel Cell Safety
Challenges: Breakthrough safety strategies and engineering solutions to
underpin safety of emerging HFC technologies
Approach: Fundamental research to close knowledge gaps:
hydrogen concentration decay in highly under-expanded jets
behaviour of under-ventilated hydrogen fires (self-extinction and
reignition)
combustion instabilities (e.g. Rayleigh-Taylor)
Applied research directions: Safety of hydrogen buses and cars
Rely on CFD expertise of HySAFER Centre
Control of release and blowdown from H2 storage
Reduction of separation distances for H2 releases, jet fires, pressure
effects of deflagrations/detonations
Research outline
PhD student Mr David Yates, thesis title “Innovative solutions to reduce separation
distances in hydrogen systems”
PhD student Mr Sergii Kashkarov, thesis title “Fire resistance of onboard high
pressure storage tanks for hydrogen-powered vehicles”
UU RA (to be hired), research to focus on hazards assessment of HFC technologies,
development of engineering safety models/tools
Other research activities in line with SUPERGEN Hub strategy:
EPSRC SUPERGEN Challenge project “Integrated safety strategies for onboard hydrogen storage” (EP/K021109/1),
EC FP7 project H2FC (“Research Infrastructures for Hydrogen & Fuel Cells facilities”),
FCH-JU projects HyIndoor (“Pre-normative research on safe indoor use of fuel cells and hydrogen systems”), SUSANA (“Support to safety analysis of hydrogen and fuel cell technologies”), HyResponse (“European Hydrogen Emergency Response training programme for First Responders”),
PhD study Mr Jean Meyer (PhD enrolment 2014, PhD title “Optimisation of onboard hydrogen storage fire resistance”),
seeding research on predicting hazards of delayed ignition of hydrogen jets
Separation distance (1/2)
“Innovative solutions to reduce separation distances in hydrogen systems”
Modelling of hazards from hydrogen jet fires
Scientifically informed measures to control of jets from H2 storage
Engineering solutions for reduction of separation distances (e.g.
plane nozzle)
Progress:
The model (Makarov and Molkov, 2013) was advanced to
account combustion in a near field and compressibility at far
field.
The results are in agreement with experiments (Mogi and
Horiguchi, 2009), and simulation (Makarov and Molkov, 2013)
Validity of applied approach in the later paper
Separation distance (2/2)
Mogi and Horiguchi,2009
Simulation
AR=12.8
AR=1.0
Simulated vs experimental H2 jet flame
Control of H2 release
Control of blowdown from H2 storage
Variable aperture TPRD targeting jet fire length ~1 m
Simulation using deforming grids (work-in-progress)
“Closed” TPRD:
700 bar, mass flow rate 4.0 g/s, flame length 1.1 m
“Open” TPRD:
37.5 bar, flow rate 1.3 g/s, flame length 0.62 m
Fire resistance
“Fire resistance of onboard high pressure storage tanks for hydrogen-powered vehicles”
Longer blowdown requires increase of storage fire resistance
Reduction of separation distances for H2 releases, jet fires
Pressure effects of tank raptures/deflagrations/detonations
Progress
Bare tank bonfire – formulated model, running simulations
Pre-tests with propane and methane-air burners in line with
Global Technical Regulation (GTR 2013)
Qualitative testing of simplified tank failure criterion (based on
temperature of resin melting)
Qualitative agreement with type 4 tanks Fire Resistance Rating
(FRR) approx. 15 min
Propane burner
Tamura et al., 2012
CFD, 336.5 kW
FRR=13 min
Methane-air pretest
KIT (Germany) facility
CFD, 336 kW
FRR=15 min
Bonfire dynamics
EPSRC project “Integrated safety strategies for
onboard hydrogen storage systems” (project No. EP/K021109/1 )
Progress at University of Ulster
Project overview
Participants
University of Ulster (Dr D Makarov, Prof V. Molkov, Dr P. Joseph)
University of Bath (Dr T. Mays)
University of Warwick (Prof J. Wen)
Motivation
Fire resistance rating (FRR) of tanks made of carbon-fibre reinforced polymer (CFRP) are
currently unacceptably low – 6-12 minutes.
To facilitate low FRR temperature activated pressure relief devices (TPRD) are designed to
release hydrogen as fast as possible, creating jet fire hazard
Hydrogen jet fires may reach up to 15 m length, safe separation distance – up to 50 m
Aim
Develop novel safety strategies and engineering solutions for onboard storage of hydrogen
Objectives
Conduct parametric studies of tank performance in fires to optimize its fire resistance
Test Type 4 tanks, demonstrate performance of proposed solutions to increase fire
resistance
Improve bonfire and TPRD test protocols, including input of fire loading;
Perform economic analysis and evaluate reduction in risk of HFC vehicles with longer fire
resistance.
Project structure
WP1. Safety strategies for onboard storage (leader UU, M1-36)
WP2. Degradation and failure mechanisms (leader UW, M1-48)
WP3. Fire resistance prediction tools (leader UU, M1-48)
WP4. Testing tank prototypes with increased fire resistance (UU,M12-36)
WP5. Novel storage and safety solutions (leader UB, M1-36)
WP6. Bonfire and PRD testing protocols, outreach programme (leader UU,
M12-48)
WP7. Socio-economic effects of hydrogen safety (leader UU, M30-48)
Fire resistant oboard storage
Fire resistance: 1-2 hour (instead of 5 min)
Flame length: less than 1 m (instead of 15 m)
Automated control of tank aging
Novel
FRR prediction tools (1/4)
Task 3.1. Fire resistance model (UU, M1-36)
Simplified failure criterion: unprotected (“bare”) tank performance
Criterion
Local temperature
at 0.44 of CFRP thickness
is equal to
resin melting temperature:
𝑇 ≥ 𝑇𝑚𝑒𝑙𝑡𝑖𝑛𝑔,
FRR prediction tools (2/4)
Task 3.2. Optimisation of fire protection solutions (UU, M18-48).
Towards development of intumescent paint coated tank bonfire performance
Tank structure Tank structure Tank structure
Unreacted coating Unreacted coating
Tank structure
Unreacted coating
reacting coating reacting coating
char
char
char
Heat flux
1. Physical process
Melting: The polymer matrix melts and degrades to form a viscous fluid
Intumescence: Components within the coating decomposes producing
gas, some fraction is trapped within the molten matrix
Char formation The molten fluid hardens
Char degradation: The char layer pyrolyses leaving inert porous matrix
Flow chart
Initialize
Calculate gas trapped
among bubbles
Calculate expansion
ratio
Compute mass fraction
in each cells
Determine bubble burst
and expansion stop
Calculate volume
fraction of bubbles and
condensed phase
Determine material
properties
Calculate temperature
field
𝐾𝑗= 𝐴𝑗𝑒𝑥𝑝 −𝐸𝑖𝑅𝑇
, 𝑗 = 1,2,3
𝜕𝑚1
𝜕𝑡= −𝑚0,1𝐾1𝑌1,
𝜕𝑚2
𝜕𝑡= −𝑚0,2𝐾2𝑌2,
𝜕𝑚3
𝜕𝑡= −𝑚0,3𝐾3𝑌3,
𝜕𝑚𝑐
𝜕𝑡= 𝜈𝑐𝑚0,3𝐾3𝑌3,
𝑚 𝑔𝑜𝑢𝑡-𝑚 𝑔
𝑖𝑛 =𝜕𝑚𝑔
𝜕𝑡 - 𝜕 𝜀𝑥𝜚𝑔
𝜕𝑡
𝑥𝑠 = 𝑥0 1 − 𝜀0𝑚𝑠
𝑚0, 𝜀 =
𝑥−𝑥𝑠
𝑥
𝜚=𝑊𝑔𝑃0
𝑅𝑇
Mass Conservation
Mass continuity
Solid phase volume
State equation
𝜕
𝜕𝑥𝜆𝜕𝑇
𝜕𝑥= 𝑚𝑠𝐶𝑠+𝑚𝑔𝐶𝑔
𝜕𝑇
𝜕𝑡 + 𝐶𝑔𝑇
𝜕 𝜀𝑥𝜚𝑔
𝜕𝑡 + 𝐶𝑠𝑇
𝜕𝑚𝑠
𝜕𝑡 + 𝐶𝑔
𝜕 𝑚 𝑔𝑇
𝜕𝑥
𝜕 𝑚𝐶𝑇𝜕𝑡
+ 𝐻𝑗𝜕𝑚𝑗
𝜕𝑡
∆𝐻
𝜆∗ = 𝜆𝑠(𝜆𝑔
𝜆𝑠𝜀23 + 1 − 𝜀
23 )/(
𝜆𝑔
𝜆𝑠𝜀23 − 𝜀 + 1 − 𝜀
23 + 𝜀)
𝜆𝑔 = 𝜆𝑐𝑜𝑛𝑑+𝜆𝑟𝑎𝑑 𝜆𝑐𝑜𝑛𝑑 = 4.815 × 10−4𝑇0.717 𝜆𝑟𝑎𝑑 =2
3× 4𝑑𝑒𝜎𝑇3
Energy conservation
2. Intumescent paint model (following Di Blasi)
Node updating
Δ𝑥𝑖 = Δ𝑥0 + ∆𝑡𝑇𝑖𝛽𝑅
𝑃0𝑊𝑉2
𝜕 𝑚2
𝜕𝑡, 𝑇𝑚 < 𝑇𝑖 < 𝑇𝑐
…(3/4)
4. Preliminary simulation of expansion process (Ansys FLUENT 14.5)
𝐾𝑗= 𝐴𝑗𝑒𝑥𝑝 −𝐸𝑖𝑅𝑇
, 𝑗 = 1,2,3
𝜕𝑚1
𝜕𝑡= −𝑚0,1𝐾1𝑌1,
𝜕𝑚2
𝜕𝑡= −𝑚0,2𝐾2𝑌2,
𝜕𝑚3
𝜕𝑡= −𝑚0,3𝐾3𝑌3,
𝜕𝑚𝑐
𝜕𝑡= 𝜈𝑐𝑚0,3𝐾3𝑌3,
Mass Conservation
𝜕
𝜕𝑥𝜆𝜕𝑇
𝜕𝑥= 𝜚𝐶𝑝
𝜕𝑇
𝜕𝑡 + 𝐻𝑗
𝜕𝑚𝑗
𝜕𝑡
∆𝐻
Energy conservation
Node updating
Δ𝑥𝑖 = Δ𝑥0 + ∆𝑡𝑇𝑖𝛽𝑅
𝑃0𝑊𝑉2
𝜕 𝑚2
𝜕𝑡, 𝑇𝑚 < 𝑇𝑖 < 𝑇𝑐
Void
Paint
Air
Computational Domain
Expanding surface
…(4/4)
UU progress summary
Research in both SUPERGEN Hub (core) and in SUPERGEN
Challenge projects are being developed as planned
PhD projects are targeted at safety solutions readily available for
practical implementation:
Reduction of separation distances in hydrogen systems
Fire resistance of high pressure storage tanks for hydrogen-
powered vehicles
Focus of SUPERGEN Challenge project is engineering of integrated
safety solutions for Type 4 tanks to be used in automotive industry
Model of bonfire tank performance was formulated; modelling of
thermal protection (intumescent paint coating) is under
development
Contribution to regulations is expected as a particular result of the
project
24
Progress at University of Warwick
Prof J. Wen, Dr Z. Saldi
WP2. Degradation and failure mechanisms
Task 2.2. Finite element analysis of tank failure
Elmer
• Open source FEM solver for multiphysical
problems.
• Fluid dynamics, structural mechanics,
electromagnetics, heat transfer, acoustics.
• Thermomechanical problem (relevant in this
project)
• http://www.csc.fi/english/pages/elmer
25
Thermomechanical solver
• Heat transfer
• Linear elasticity
26
rcp¶T
¶t+ u ×Ñ( )T
æ
èç
ö
ø÷-Ñ× kÑT( ) = t :e + rSh
convective term (neglected) frictional viscous heating (neglected)
r¶2d
¶t2-Ñ×t = f
Initial test case: pressure vessel
• Ref:
www.openeering.com/sites/default/files/
Thermo_Elasticity_Scilab.pdf
Constant internal pressure of 1MPa
28
Results: temperature
Elmer
Ref
29
Test case: Acetylene cylinders in fire
• Ferrero et al., J. Loss
Prevention in the Process
Industries 25 (2012) 364-372
• Heat conduction problem,
convection neglected
• With heat release due to
decomposition reaction
• Fully enveloped by fire (heat
flux b.c due to convection &
radiation)
Acetylene
Steel AISI 4340
31
Sh = -Ae
-Ea
RT
æ
èç
ö
ø÷
Qdec
Initial results: inner shell temperature
(no decomposition reaction)
Cylinder radius = 0.115 m, height = 1.06 m 32
Test case for decomposition
reaction
33
Top & bottom: insulated wall
Cylinder heated at 325 K
Convective
outlet
Inlet vel =
5e-4 m/s
cA =
1000 mol/m3
Decomposition reaction: A kA¾ ®¾ F kA = Ae-Ea
RT
æ
èç
ö
ø÷
COMSOL model gallery, ID: 2164
Test case for decomposition
reaction
36
Left/right: temperature/species concentration
Top/bottom: without/with heat release
Stronger thermal decomposition in the hot area
close to the cylinder
Test case for decomposition
reaction
37
Summary
• Satisfying results from test cases on
thermo-mechanical & thermal
decomposition problem using Elmer
• Work in progress to couple thermo-
mechanical & thermal decomposition
aspects
• Elmer promising tool
• Basic know-how achieved 38
WP5: Novel storage and safety solutions
Co-I, Tim Mays, Chemical Engineering, Bath (15/10/13 – 14/10/17) 36 month FT PDRA, Dr Nuno Bimbo (17/2/14 – 16/2/17)
(funded from project) 36 month FT PhD student , Leighton Holyfield (1/10/14 – 30/9/17) (funded from University and EPSRC CDT in Sustainable Technologies)
Task 5.1: Review of innovative storage solutions (M1-6)
Focus on hybrid sorbent / high-pressure gas storage systems
Task 5.2: Comparative analysis of storage safety options (M3-36)
What are the key design and safety challenges and options for hybrid
sorbent / high-pressure gas storage systems?
Workpackage Details @ Bath
Concept
Safety aspects of integrating nanoporous sorbents into Type IV tanks
metal-organic frameworks
polymers of intrinsic microporosity
activated arbons
…
currently 70 MPa, 300 K
Compare physisorption with compressed gas
PC Storage pressure
Adsorptive storage
Compressed gas
Adsorption
favoured
Compression
favoured
Am
ou
nt o
f sto
red
hyd
rog
en
Modelling
0 5 10 15 20 25
0
10
20
30
40
5089 K - TE7 carbon beads
Hydro
gen u
pta
ke /
g L
-1
Absolute pressure, P / MPa
empty of adsorbent
quarter full of adsorbent
half full of adsorbent
full of adsorbent
Sorption Data
Research Questions
• Nanoporous sorbents in tanks increase volumetric
capacity at low pressures and temperatures
• Do these benefits extend to temperatures near
ambient?
• Are some sorbents “better” than others?
• Charge hybrid tank at cryogenic temperatures
and low pressures then allow warming to
ambient, with a consequent pressure rise. Is
this safe and techno-economically feasible?
Thank you!