1. Extinction Simulation of a Diffusion Flame Established in Microgravity presented by Guillaume Legros (1) ( legros@lcd.ensma.fr ) in collaboration with A. Fuentes (1), B. Rollin (1), P. Joulain (1), J.P. Vantelon (1), and J.L. Torero (2) (1) Laboratoire de Combustion et de Détonique (UPR 9028 du CNRS) – Poitiers (France) (2) School of Engineering and Electronics, The University of Edinburgh – Edinburgh (United Kingdom) 4 th International Conference on Computational Heat and Mass Transfer Cachan, May, 19 th, 2005

2. Plausible Spacecraft Fire Scenario: INTRODUCTION EXPERIMENT SIMULATION COMPARISON CONCLUSIONS condensed fuel oxidizer blowing velocity: V ox

3. Plausible Spacecraft Fire Scenario: INTRODUCTION condensed fuel oxidizer blowing velocity: V ox extinction ! INTRODUCTION EXPERIMENT SIMULATION COMPARISON CONCLUSIONS

4. Investigating extinction:  O 2 level  oxidizer balance gaz  V OX  condensed fuel nature INTRODUCTION need of valuable numerical simulations INTRODUCTION EXPERIMENT SIMULATION COMPARISON CONCLUSIONS

5. Investigating extinction:  O 2 level  oxidizer balance gaz  V OX  condensed fuel nature INTRODUCTION need of valuable numerical simulations INTRODUCTION EXPERIMENT SIMULATION COMPARISON CONCLUSIONS

6. Investigating extinction:  O 2 level  oxidizer balance gaz  V OX  condensed fuel nature INTRODUCTION need of valuable numerical simulations INTRODUCTION EXPERIMENT SIMULATION COMPARISON CONCLUSIONS

7. Investigating extinction:  O 2 level  oxidizer balance gaz  V OX  condensed fuel nature INTRODUCTION need of valuable numerical simulations INTRODUCTION EXPERIMENT SIMULATION COMPARISON CONCLUSIONS

8. Investigating extinction:  O 2 level  oxidizer balance gaz  V OX  condensed fuel nature INTRODUCTION need of valuable numerical simulations for steady-state phenomena INTRODUCTION EXPERIMENT SIMULATION COMPARISON CONCLUSIONS

9. Experimental Environment: Parabolic flights  microgravity duration = 22 s  a parabola every 2 minutes EXPERIMENTAL PROCEDURE easy ignition + fast transition to steady-state INTRODUCTION EXPERIMENT Environment Measurement SIMULATION COMPARISON CONCLUSIONS

10. EXPERIMENTAL PROCEDURE easy ignition + fast transition to steady-state INTRODUCTION EXPERIMENT Environment Measurement SIMULATION COMPARISON CONCLUSIONS

11. Experimental Environment: Parabolic flights  microgravity duration = 22 s  a parabola every 2 minutes EXPERIMENTAL PROCEDURE easy ignition + fast transition to steady-state INTRODUCTION EXPERIMENT Environment Measurement SIMULATION COMPARISON CONCLUSIONS

12. Experimental Environment: Parabolic flights  microgravity duration = 22 s  a parabola every 2 minutes EXPERIMENTAL PROCEDURE easy ignition + fast transition to steady-state INTRODUCTION EXPERIMENT Environment Measurement SIMULATION COMPARISON CONCLUSIONS

13. Experimental Environment: Parabolic flights  microgravity duration = 22 s  a parabola every 2 minutes EXPERIMENTAL PROCEDURE easy ignition + fast transition to steady-state INTRODUCTION EXPERIMENT Environment Measurement SIMULATION COMPARISON CONCLUSIONS

14. Experimental Environment: EXPERIMENTAL PROCEDURE easy ignition + fast transition to steady-state oxidizer blowing velocity: V ox ethylene injection velocity: V F 1 cm INTRODUCTION EXPERIMENT Environment Measurement SIMULATION COMPARISON CONCLUSIONS

15. Experimental Measurement: EXPERIMENTAL PROCEDURE INTRODUCTION EXPERIMENT Environment Measurement SIMULATION COMPARISON CONCLUSIONS

16. Experimental Measurement: CH * chemiluminescence I flame (λ=431 nm) α I CH* [1] [1] Berg et al. (2000) EXPERIMENTAL PROCEDURE INTRODUCTION EXPERIMENT Environment Measurement SIMULATION COMPARISON CONCLUSIONS

17. Experimental Measurement: CH * chemiluminescence I CH* α volumetric combustion rate [2] [2] McManus et al. (1995) EXPERIMENTAL PROCEDURE INTRODUCTION EXPERIMENT Environment Measurement SIMULATION COMPARISON CONCLUSIONS

18. Experimental Measurement: Map by CH* chemiluminescence EXPERIMENTAL PROCEDURE oxidizer blowing velocity: V ox ethylene injection velocity: V F 1 cm INTRODUCTION EXPERIMENT Environment Measurement SIMULATION COMPARISON CONCLUSIONS

19. Experimental Measurement: Map by CH* chemiluminescence EXPERIMENTAL PROCEDURE oxidizer blowing velocity: V ox 1 cm α map of volumetric combustion rate INTRODUCTION EXPERIMENT Environment Measurement SIMULATION COMPARISON CONCLUSIONS

20. Validating numerical extinction:  O 2 level = 35%  oxidizer balance gaz = N 2  fuel = C 2 H 4  V ox = parameter comparison based on volumetric combustion rate NUMERICAL PROCEDURE INTRODUCTION EXPERIMENT SIMULATION Goal Tool Domain COMPARISON CONCLUSIONS

21. Validating numerical extinction:  O 2 level = 35%  oxidizer balance gaz = N 2  fuel = C 2 H 4  V ox = parameter comparison based on volumetric combustion rate NUMERICAL PROCEDURE INTRODUCTION EXPERIMENT SIMULATION Goal Tool Domain COMPARISON CONCLUSIONS

22. Validating numerical extinction:  O 2 level = 35%  oxidizer balance gaz = N 2  fuel = C 2 H 4  V ox = parameter comparison based on volumetric combustion rate NUMERICAL PROCEDURE INTRODUCTION EXPERIMENT SIMULATION Goal Tool Domain COMPARISON CONCLUSIONS

23. Validating numerical extinction:  O 2 level = 35%  oxidizer balance gaz = N 2  fuel = C 2 H 4  V ox = parameter comparison based on volumetric combustion rate NUMERICAL PROCEDURE INTRODUCTION EXPERIMENT SIMULATION Goal Tool Domain COMPARISON CONCLUSIONS

24. Validating numerical extinction:  O 2 level = 35%  oxidizer balance gaz = N 2  fuel = C 2 H 4  V ox = parameter comparison based on the map of volumetric combustion rate NUMERICAL PROCEDURE INTRODUCTION EXPERIMENT SIMULATION Goal Tool Domain COMPARISON CONCLUSIONS

25. Numerical Tool: Variant of Fire Dynamics Simulator (FDS):  transient 3D Navier-Stokes equations (low Mach number approximation)  allowing large density and temperature changes  Direct Numerical Simulation  mixture fraction / finite kinetics – no soot model  Radiative Transfer Equation (non-scattering approximation) RTE  Finite Volume Method  Wideband model ( H 2 O + CO 2 ) NUMERICAL PROCEDURE INTRODUCTION EXPERIMENT SIMULATION Goal Tool Domain COMPARISON CONCLUSIONS

26. Numerical Tool: Variant of Fire Dynamics Simulator (FDS):  transient 3D Navier-Stokes equations (low Mach number approximation)  allowing large density and temperature changes  Direct Numerical Simulation  mixture fraction / finite kinetics – no soot model  Radiative Transfer Equation (non-scattering approximation) RTE  Finite Volume Method  Wideband model ( H 2 O + CO 2 ) NUMERICAL PROCEDURE INTRODUCTION EXPERIMENT SIMULATION Goal Tool Domain COMPARISON CONCLUSIONS

27. Numerical Tool: Variant of Fire Dynamics Simulator (FDS):  transient 3D Navier-Stokes equations (low Mach number approximation)  allowing large density and temperature changes  Direct Numerical Simulation  mixture fraction / finite kinetics – no soot model  Radiative Transfer Equation (non-scattering approximation) RTE  Finite Volume Method  Wideband model ( H 2 O + CO 2 ) NUMERICAL PROCEDURE INTRODUCTION EXPERIMENT SIMULATION Goal Tool Domain COMPARISON CONCLUSIONS

28. Numerical Tool: Variant of Fire Dynamics Simulator (FDS):  transient 3D Navier-Stokes equations (low Mach number approximation)  allowing large density and temperature changes  Direct Numerical Simulation  mixture fraction / finite kinetics – no soot model  Radiative Transfer Equation (non-scattering approximation) RTE  Finite Volume Method  Wideband model ( H 2 O + CO 2 ) NUMERICAL PROCEDURE INTRODUCTION EXPERIMENT SIMULATION Goal Tool Domain COMPARISON CONCLUSIONS

29. Numerical Tool: Variant of Fire Dynamics Simulator (FDS):  transient 3D Navier-Stokes equations (low Mach number approximation)  allowing large density and temperature changes  Direct Numerical Simulation  mixture fraction / finite kinetics – no soot model  Radiative Transfer Equation (non-scattering approximation) RTE  Finite Volume Method  Wideband model ( H 2 O + CO 2 ) NUMERICAL PROCEDURE INTRODUCTION EXPERIMENT SIMULATION Goal Tool Domain COMPARISON CONCLUSIONS

30. Numerical Tool: Variant of Fire Dynamics Simulator (FDS):  transient 3D Navier-Stokes equations (low Mach number approximation)  allowing large density and temperature changes  Direct Numerical Simulation  mixture fraction / finite kinetics – no soot model  Radiative Transfer Equation (non-scattering approximation) RTE  Finite Volume Method  Wideband model ( H 2 O + CO 2 ) NUMERICAL PROCEDURE INTRODUCTION EXPERIMENT SIMULATION Goal Tool Domain COMPARISON CONCLUSIONS

31. Methodology: choice of the iso-contour value? Sum of volumetric combustion rate threshold Max 10 % of Max Iso-contour value COMPARISON INTRODUCTION EXPERIMENT SIMULATION COMPARISON Methodology Stand-off distance Flame length Soot role CONCLUSIONS

32. Stand-off Distance: iso-contours V OX VFVF COMPARISON INTRODUCTION EXPERIMENT SIMULATION COMPARISON Methodology Stand-off distance Flame length Soot role CONCLUSIONS

33. Flame Length: COMPARISON INTRODUCTION EXPERIMENT SIMULATION COMPARISON Methodology Stand-off distance Flame length Soot role CONCLUSIONS

34. Flame length: INTRODUCTION CURSUS ENSEIGNEMENT Cadre Expériences RECHERCHE Cadre Expériences CONCLUSIONS

35. Discrepancy Evolution: COMPARISON INTRODUCTION EXPERIMENT SIMULATION COMPARISON Methodology Stand-off distance Flame length Soot role CONCLUSIONS

36. Discrepancy Evolution: V OX =150 mm.s -1 V OX =250 mm.s -1 characteristic residence time V OX COMPARISON INTRODUCTION EXPERIMENT SIMULATION COMPARISON Methodology Stand-off distance Flame length Soot role CONCLUSIONS

37. This study achieved :  coupling of radiative transfer and finite kinetics, leading to flame extinction simulation, thus better flame shape predictions  highlight the soot keyrole in the extinction at the flame trailing edge This study needs to achieve :  incorporation of a soot model CONCLUSIONS INTRODUCTION EXPERIMENT SIMULATION COMPARISON CONCLUSIONS

38. This study achieved :  coupling of radiative transfer and finite kinetics, leading to flame extinction simulation, thus better flame shape predictions  highlight the soot keyrole in the extinction at the flame trailing edge This study needs to achieve :  incorporation of a soot model CONCLUSIONS INTRODUCTION EXPERIMENT SIMULATION COMPARISON CONCLUSIONS

39. Enjeu: utilisation de l’échelle des temps de résidence pour l’étude de l’extinction de la réaction par les pertes radiatives Techniques expérimentales Analyse dimensionnelle de la couche-limite réactive: Résultats: fraction volumique de suie mesurée et rapportée à expérimental théorie

40. Techniques expérimentales Echéance:caractérisation des conditions ( T suie, f suie ) dans la zone de quenching Incandescence Induite par Laser Emission/Absorption Modulée étalonnage z y x z y x

41. Enjeu: appréhender la dynamique de l’interaction flamme non- prémélangée / particules Techniques expérimentales t ouverture caméra flash laser Résultats: Echéance:couplage de techniques pour cerner le couplage aérodynamique des flammes / formation des suies LIF LII intensité induite

42. APPENDIX X=0,1X=0,5X=0,98X=1,1 V ox =100 mm.s -1

43. Computational Domain: NUMERICAL PROCEDURE INTRODUCTION EXPERIMENT SIMULATION Goal Tool Domain COMPARISON CONCLUSIONS

44. z = 0: u = 0 T = T w  w = 0,95 y = 0: grad u = 0 T = T a  = 1 x = 0: u = V ox T = T a  = 1 y = y max : grad u = 0 T = T a  = 1 z = z max : grad u = 0 T = T a  = 1 x = x max : grad u = 0 T = T a  = 1 g = 0