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UBC Mechanical Engineering CFD Modeling Group

Dr. Martha SalcudeanWeyerhaeuser Industrial Research ChairFellow C.S.M.E., F.C.A.A., F.R.S.C.

Dr. Ian GartshoreFellow C.A.S.I

PULP AND PAPER COMPUTATIONAL FLUID DYNAMICS APPLICATIONS

Objectives:

• Predict and control fiber fractionation according to wood species

• Develop a model of flexible fiber motion that includes wall interaction

• Compute trajectories of fibers in complex flows

• Model fractionation during screening and in hydrocyclones

Benefits:

• Improve supply of uniform fibers and increase quality and consistency of pulp

FLUID-FIBER INTERACTION

Objectives:

• Determine the air flow and moisture distribution in wood kilns

• Optimize kiln operations and improve wood quality

Model:

• 3-D curvilinear non-orthogonal computational method with transient mass and heat transfer calculations to model the drying process

End-Users:

• Kiln operators and manufactures

WOOD KILNS

Objectives:

• Develop a 3-D steady-state computational model to predict the flow and heat transfer in the lime kiln

• Use the model to solve problems in kiln operation and design

Model:

• Block-structure body-fitted coordinates with domain segmentation, implementation of vortex stretching model, combustion, radiation, and 3-D modeling of the non-Newtonian nature of the lime mud

Benefits:

• Maintain maximum operating efficiency for lime kiln and reduce energy consumption

LIME KILNS

Objectives:

• Develop a comprehensive bark boiler gas flow and combustion model

• Optimize the thermal efficiency and emissions of boilers and identify promising and cost-effective design upgrades

Model:

• Momentum and conservation equations for mass, energy and gas species concentration using the turbulence k- model are solved simultaneously

• Chip combustion includes the evaporation of water, release of volatile gases and gas radiation heat transfer

End-Users:

• Bark boiler operators and manufacturers

BARK BOILERS

FUNDINGFUNDING

- - NSERC- FRBC- B.C. Science Council- Weyerhaeuser- CANFOR- PSL

12

10

8

6

4

2

0

-2

-4

W [m /s]

50m/s

U ndergrate A ir 70,000 kg/hr

Objectives:

• Develop modeling tools to improve existing designs and operating procedures, and to lower carry-over and environmental load

• Analyze performance of different air systems and liquor firing strategies

Model:

• 3-D orthogonal computational method with k- turbulent model, liquor combustion, particle tracking, and wall and gas radiation

• Flow equations coupled to the energy and species conservation equations

• Predicts gas flows, composition, temperature, and liquor-smelt-char particulate distribution

Benefits:

• Powerful modeling tool to optimize recovery boilers, reduce plugging rates, reduce time between water washes, analyze performance of different air systems, improve operating procedures, lower carry-over, and reduce environmental load

RECOVERY BOILERS

Zhengbing Bian Paul Nowak

Eric Bibeau Mohammad Shariati

Suqin Dong Emil Statie

Xioasi Feng David Stropky

Mike Georgallis Zhu Zhi Xiao

Pingfan He Jerry Yuan

Jason Zhang Kegang Zhang

5 10 15 200.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

R=0%

R=8%

R=15%

Tube Position

Ave

rage

Vel

ocity

(m/s

)

Objectives:

• Investigate experimentally flows in headboxes with a range of fiber concentration

• Develop computational-based methods to simulate the complex flows occurring in headboxes

Model:

• 3-D curvilinear non-orthogonal computational method with low Reynolds k- model and with non-isotropic, non-linear versions of the k- model

End-Users:

• Headbox manufactures and paper mills

HEADBOXES

ws0.00100.0002-0.0006-0.0014-0.0021-0.0029-0.0037-0.0045-0.0053-0.0061-0.0069-0.0076-0.0084-0.0092-0.0100

Axial ChipVelocity

Cold BlowNozzles(15 l/s)

WashDischarge(25 l/s)

Upper CookDischarge(85 l/s)

QuenchDischarge(4 l/s) Extraction

Screens(42 l/s)

LowerCookScreens(120 l/s)

UpperCookScreens(85 l/s)

Lower CookDischarge(120 l/s)

Blowline

Chips (26.5 l/s)Liquor (40 l/s)

w0.00200.00150.00100.00050.0000-0.0005-0.0010-0.0015-0.0020-0.0025-0.0030-0.0035-0.0040-0.0045-0.0050

AxialLiquorVelocity

Cold BlowNozzles(15 l/s)

WashDischarge(25 l/s)

Upper CookDischarge(85 l/s)

QuenchDischarge(4 l/s)

ExtractionScreens(42 l/s)

LowerCookScreens(120 l/s)

UpperCookScreens(85 l/s)

Lower CookDischarge(120 l/s)

Blowline

Chips (26.5 l/s)Liquor (40 l/s)

Objectives:

• Model the delignification process occurring within digesters

• Calculation of liquid and solid conservation equations for multi-dimensional flow

Model:

• Liquid-solid two-phase flow model coupled to the energy and conservation of species equations

Benefits:

• Better understanding of process to improve yield and fiber strength

Y

Z

X

5003002001501007550302010

NO *106

massfraction

BASE CASEUGA 1m/sOFA 30m/s

MODIFIED CASEUGA 0.8m/s20% of UGA moved to OFAOFA interlaced, 60m/s:30/s

Y

Z

X

5003002001501007550302010

NO *106

massfraction

---- drying

---- pyrolysis

---- char

---- smelt

Base Modified

x

z

-0.0025 0 0.0025

-0.004

-0.0035

-0.003

-0.0025

-0.002

-0.0015

-0.001

-0.0005

0

0.0005

0.001

Fiberpassesthroughtheslotaftercontactingslotwall

1

23

-4 -2 0 2 4

-4

-2

0

2

4

Flexible Fiber Rotation

Objectives:

• Improve predictions of swirling flows

• Develop mathematical models to predict the classification of fibers

Model:

• Discretization using block structured curvilinear grids

• Modified k- model for highly curved turbulent flows

• Particle tracking through explicit time marching based on force balance

End-Users:

• Pulp mills requiring high efficiencies for fiber cleaning and fractionation

HYDROCYCLONESDIGESTERS

Other Institutions

Government Industry

TECHNOLOGY TECHNOLOGY TRANSFER

License agreement

Serviceagreements

Consultingagreements

Customagreements

Licenseagreements

PSL

0

10

20

30

40

50

60

70

80

90

100

12

34

56

1020

3040

5060

70

89.677.765.753.841.829.917.96.0

diameter (microns)

length (mm)

carried over (%)

x (m)

r(m)

0 0.1 0.2 0.3 0.4 0.50

0.02

0.04

x (m)

r(m)

0 0.1 0.2 0.3 0.4 0.50

0.02

0.04

152430501423610013229150122222001121525010208300920135081944007187450618050051735504166600315965021527001145750

x (m)

r(m)

0 0.1 0.2 0.3 0.4 0.50

0.02

0.04

2.82.72.52.32.11.91.71.51.31.10.90.80.60.40.2