1. Numerical Simulation of Premix Combustion with Recirculation
MAE 5310 Final Presentation
Fumitaka Goto
Instructor:Dr.D.Kirk
Dec13th,2005

2. Modeling of Gas Turbine Engines
Flow
Recirculation
Unsteady
Turbulence
Mixing
Phase change
Chemical Kinetics
Turbulence Combustion
Flame Speed
evaporation
Large/Small Eddys…etc
COMPLEX!
Simulation of Flow within aPW gas turbine-combustor
UofMinesota

3. Motivation Recirculation is observed within IC engines
Simulation identifies hot temperature region
Production of NOx and radicals
Stress/strain on structures
More economical than experiments
Enables to predict lean fuel blow out (LBO)
Fuel efficient design
Safety Improvement

4. Alternative Topic: 2-DSimulation
Axi-Symmetric Ceramic Combustor
Laminar Flame let
Experimental data available
Discrepancy with
Numerical Computation
-One Point Probability Distribution Function
288K
60m/s
(mm)
Reactor Details with Contour of eddy lifetime 10-4 s (top)
And turbulent heat release rate GW m-3 (bottom) [Derek]

5. Lean Methane-Air (f =0.84)
[Derek]

6. Preliminarily Interest: Lean Methane-Air (f =0.63)
[Derek]

7. Fluent Modeling-1 Finite Rate Chemistry 5 step mechanism
[Fluent 6.2 User`s Guide] &[Kirk]

8. Convergence and Meshing
Premix off
Energy off
2nd Order Upwind E A B
1st Order D
Ref: [Fluent Inc. July Tutorial]

9. Static Temperature
Ref: [Fluent Inc. July Tutorial]

10. Molar Concentration CH4

11. Molar Concentration CO

12. Molar Concentration CO2

13. Molar Concentration O2

14. Molar Concentration H2O

15. Molar Concentration N2

16. Molar Concentration NO

17. Molar Concentration of CO2 &CO

18. Fluent Modeling -2 Zimount Model c mean reaction progress variable
Dt the turbulent diffusivity
_ ru density of the unburned mixture
Ut the turbulent flame speed
Global mechanism
Fluent 6.2 User`s Guide and [Lipantikov]

19. Velocity Contour
Zimount
Zimount

20. Temperature B
5 step Finite Rate
Zimount

21. Turbulent Kinetic Energy and Turbulent Flame Speed
Sudden Expansion in Cross section area
Increase due to mixing ?
Velocity Increase due to recirculation

22. Reaction Rate

23. Conclusion & Recommendation
Five Step Model needs modification
25 or 26 steps might give better correlation
Zimount show the rate of global reaction,
which is governed by oxidation of carbon dioxide.
Further comparison between CFD and experiment necessary
Also check the influence meshing schemes