Premixed Turbulent Combustion Modeling PhD student: Ehsan Yasari - - PowerPoint PPT Presentation

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Premixed Turbulent Combustion Modeling

PhD student:

Ehsan Yasari

yasari@chalmers.se

Supervisor:

Andrei Lipatnikov

Department of Applied Mechanics Chalmers University of Technology

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Outline

• Project Description
• Tools and Solver
• Results
• Problems and Difficulties
• Possible Solutions

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• Turbulent Flame Closure (TFC)
• Flame Speed Closure (FSC)

Goals

• Simulation of different premixed turbulent flames
• Turbulent combustion flux and local burning velocity

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• OpenFOAM
• XiFoam solver: compressible premixed/partially-

premixed combustion with turbulence modeling

• Combustion model: based on Weller1 model

Tools and Solver

|-- UEqn.H |-- XiFoam.C |-- bEqn.H |-- createFields.H |-- ftEqn.H |-- hEqn.H |-- huEqn.H |-- pEqn.H `-- readCombustionProperties.H

• 1:Weller HG, Uslu S, Gosman AD, Maly RR, Herweg R, Heel B. COMODIA 94, Yokohama: JSME,
• 1994. p.163

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



~ ~ Pr

2 ,

k C D t 



                

 L t t

t D D  exp 1

,

Model FSC t t t U U

L L L t t 2 1 ,

exp 1                  



  

TFC and FSC Model:

   

c U x c D x c u x c t

t u k t k k k

~ ~ ~ ~ ~

, ,

                   

 

    Model TFC u Da u U

c t t 4 1 4 1 ,

' 5 . ' 5 .          



 

2 ,

u D t

L

 





Taylor theory of turbulent diffusion

• Zimont, V.L., and Lipatnikov, A.N., 1995, Chem. Phys. Reports, Vol. 14, pp. 993-1025
• Lipatnikov, A.N., and Chomiak, J., 2002, Prog. Energy Combust. Sci., Vol. 28, pp. 1-74.

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Simulated Test Case

• P. Moreau, “Turbulent Flame Development in High Velocity Premixed Flow”,

AIAA 15th Aerospace Sciences Meeting, 1977 High Turbulence intensity

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Numerical Setup

• Geometry: 1300*100 mm
• Mesh Independency: 325*25 , 650*50, 1300*120
• Unsteady solver
• Turbulence Model:
• k-e
• Launder Sharma
• RNG
• Realizable k-e
• Combustion Model:
• Turbulent Flame Closure (TFC)
• Flame Speed Closure (FSC)
• Boundary and Initial Conditions
• Different Equivalence Ratio:

0.62, 0.80, 0.83, 0.85, 0.87, 1, 1.24

• High Turbulence intensity: ku= 100 m2/s2

kb= 793 m2/s2

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Best Turbulent Pr and Dissipation Rate for TFC and FSC at Phi=0.80

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V-shape Flame:

• Lean premixed turbulent combustion
• Low turbulence intensity: k = 0.1 m2/s2
• F. Dinkelacker, S. Hözler “Investigation of a Turbulent Flame Speed Closure Approach for Premixed

Flame Calculations”, Combustion Science and Technology, Vol. 158, pp. 321-340, 2000

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• Time dependent term in FSC model

Problems and Difficulties

Model FSC t t t U U

L L L t t 2 1 ,

exp 1                  



  

                

 L t t

t D D  exp 1

, input

U x t 

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Time Dependent term problem:

2 1 ,

exp 1                  

 L L L t t

t t t U U   

2 ,

u D t

L

 



 58 .   58 .  

                

 L t t

t D D  exp 1

,





~ ~ Pr

2 ,

k C D t 



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Possible Solution:

x dx dT x T x T     ) ( ) 1 ( x dx dU x U x U x U x U U x x dx dD x D x D U x x D

L L L L

                             ) ( ) 1 ( ) exp( 1 ) exp( 1 ) ( ) 1 ( ) exp( 1 ) (    

x-1 x x+1

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Thank you for your attention