1. Vortragstitel 1 Kinetic Mechanism For Low Pressure Oxygen / Methane Ignition and Combustion N.A. Slavinskaya, M. Wiegand, J.H. Starcke, U. Riedel, O.J.Haidn Institute of Combustion Technology, Institute of Space Propulsion, German Aerospace Centre (DLR)

2. Folie 2 Vortragstitel 2 Introduction Methane in Aerospace Propulsion in Europe Kinetic Mechanisms for O 2 /CH 4 Low Pressure Methane Combustion Mechanism Development Mechanism Validation Analysis Pollution formation: CO, NO x, PAH Conclusions & Outlook OVERVIEW

3. Folie 3 Vortragstitel 3 CH 4 - related Propulsion Activities in Europe Development of detailed and reduced chemical kinetic schemes for high pressure CH 4 /O 2 combustion including the formation of soot precursors (PAH) (EU FP6 project LAPCAT 1, closed 2008) CFD modeling injection and combustion and nozzle performance studies of CH 4 /O 2 at low pressure using commercial and in-house CFD tools (EU FP7 project GRASP, ongoing) Chemical Kinetics Modeling and CFD modeling for CH 4 /O 2 Ignition (EU FP7 project ISP-1, ongoing) Establishment of CH 4 /O 2 Thermodynamic and Transport Properties Data Base (EU FP7 project ISP-1, ongoing) Numerical Studies and Chemical Modeling

4. Folie 4 Vortragstitel 4 CH 4 - related Propulsion Activities in Europe LOX/LCH 4 and GOX/GCH 4 ignition and combustion studies (EU FP7 project ISP-1, ongoing) LOX/CH 4 gas generator (fuel rich) ignition studies (EU FP7 project LAPCAT II, ongoing) CH 4 film cooling (EU FP7 project ISP-1, ongoing) LOX/CH 4 staged combustion testing at P8 (FLPP, closed 2009) LOX/CH 4 subscale testing at FAST 2 (Avio, nat. program, closed 2009) LOX / CH 4 LM10-Mira demo testing at CADB (Avio, nat. program, 2011) Experimental Studies

5. Folie 5 Vortragstitel 5 The detailed investigations of the interaction of the rocket plumes, i.e. the exhaust gases, particles of the propellants with the atmosphere. MOTIVATION The final step of the reaction mechanism development is its extension to the NOx sub mechanism. The large number of launches is foreseen, which exceeds by far the current launch rate of about 40 launches per year. Numerical Studies and Chemical Modeling the possible formation of CO, CO 2, NO, NO 2, N 2 O, and PAHs.

6. Folie 6 Vortragstitel 6 Methane kinetic mechanisms and their validation data base ISP-I operating conditions 0.001 atm < p < 1 atm and 0.5 < Ф < 3.0

7. Folie 7 Vortragstitel 7 Input Model: DLR_LS Mechanism Sub Mechanism Species/ Reaction Validation Parameters Validation Data CH4/CH3OH/O2/ Air 46 / 398 (93 / 729) p = 1- 60 bar,  = 0,5 – 2, T 0 = 300 – 1200 K Laminar flame speed, Ignition delay times, PAH/Soot Formation consistent hierarchical structure “first principals” continuous adaptation, validation and optimization of the kinetic characteristics Slavinskaya, Frank, Comb.Flame, 2009 Slavinskaya, Haidn, AIAA 2008-1012, 2008

8. Folie 8 Vortragstitel 8 New data provoked with the syngas activities, validated on the syngas data Mechanism development : strategy A.Konnov Mechanism

9. Folie 9 Vortragstitel 9 ReactionMean value  % H + O2 = OH + O8,22E-148,19 OH + H2 = H2O + H2,12E-1210,53 H2 + O =OH + H3,54E-1320,82 H+HO2 = H2 + O22,92E-1135,10 H2O2 + H = HO2 + H21,11E-1251,36 OH + OH (+M) =H2O2(+M)3,05E-321,99 H + O2 (+M) = HO2 (+M)1,01E-3211,67 O2 + CO = CO2 + O1,29E-2233,90 CO + O (+M) =CO2 (+M)6,58E-3482,31 CO + OH =CO2 + H2,55E-1343,36 CO + HO2 =CO2 + OH9,54E-1656,95 HCO (+M) = H + CO (+M)5,83E-1430,20 Mean values and deviations for reaction rates in H 2 /CO subsystem calculated from data of 7 different reaction models at T=1000K 1.8 – 57.4 % Slavinskaya Starke, Riedel, 2011, in preparation for H 2 /CO mixtures

10. Folie 10 Vortragstitel 10 Review and actual data for reaction rates : H 2 /CO subsystem 2H+AR = H2+AR 2H+N2 = H2+N2 2H+H2O = H2+H2O 2H+H = H2+H OH+H2 = H2O+H 2OH(+M) = H2O2(+M) H2O2(+AR) = 2OH(+AR) H2O2(+N2) = 2OH(+N2) OH+OH (+ H2O) = H2O2 (+ H2O) O2+H(+M) = HO2(+M) O2+H(+AR) = HO2(+AR) O2+H(+H2O) = HO2(+H2O) H+O2(+HE) = HO2(+HE) H+O2(+O2) = HO2(+O2) H+O2(+H2O) = HO2(+H2O) 2O+M = O2+M H+OH+M = H2O+M H+O+M = OH+M H+HO2 = H2+O2 H+HO2 = 2OH HCO+M = H+CO+M H2+O2 = OH + OH CO+O+M = CO2+M CO+HO2 = CO2+OH Baulch, D.L., Cobos, C.J., 1994 Wooldridge, M.S., Hanson R.K., et al.,1996 Isaacson, A.D., 1997 Karach, S.P., Osherov, V.I.,1999 Baulch, D.L., Bowman, C.T. et al., 2005 You, X., Wang, H., et al., 2007 Konnov, A., 2008 Shatalov, O.P., Ibraguimova, L.B., et al.,2009

11. Folie 11 Vortragstitel 11 Mechanism validation: experimental data base

12. Folie 12 Vortragstitel 12 Mechanism validation: low pressure ignition

13. Folie 13 Vortragstitel 13 Mechanism validation: low pressure flame speed Exp. Ombrello et al., 2011, p=0.16 atm.

14. Folie 14 Vortragstitel 14 Mechanism validation: low pressure laminar flame P = 25 Torr

15. Folie 15 Vortragstitel 15 Mechanism validation: low pressure laminar flame, p=0.05 atm

16. Folie 16 Vortragstitel 16 Mechanism validation: low pressure laminar flame, p=0.05 atm

17. Folie 17 Vortragstitel 17 Mechanism validation: low pressure laminar flame, p=0.05 atm

18. Folie 18 Vortragstitel 18 Mechanism validation: CO/H2 sub mechanism

19. Folie 19 Vortragstitel 19 Mechanism validation: NOX sub mechanism CH 4 /air laminar premixed flame data, p = 1.0 atm, Ф = 0.6.

20. Folie 20 Vortragstitel 20 Mechanism validation: NOX sub mechanism ac JSR concentration profiles for CH4/O2/NO/N2 mixture, p = 1.0 atm, Ф = 0.1, residents time 120ms. Dagaut, P., Nicolle, A.,2005

21. Folie 21 Vortragstitel 21 Reactor network chain schematic Interaction of exhaust gas with the atmosphere Model schematic for rocket engines

22. Folie 22 Vortragstitel 22 Reactor input data for calculations

23. Folie 23 Vortragstitel 23 Simulations: Temperature distribution in exhaust

24. Folie 24 Vortragstitel 24 Simulations: CO and CO2 distribution in exhaust High concentration

25. Folie 25 Vortragstitel 25 Simulations: NO distribution in exhaust High concentration

26. Folie 26 Vortragstitel 26 Simulations: NO2 distribution in exhaust Low concentration

27. Folie 27 Vortragstitel 27 CONCLUSIONS Low Pressure O 2 /CH 4 Kinetic Mechanisms developed as further extension of DLR_LS mechanism for operating conditions 0.03 atm < p < 1 atm, 300 K < T 0 < 1800 K and 0.36 < Ф < 2.0 Extension of Low Pressure Scheme towards Rocket Plume Chemistry (NOx, CO, PAHs) Simulations of the low pressure reactions in the exhaust plume of a CH4/LOX rocket engine under the strato- and mesosphere conditions (0.1 - 0.01 bar) shown that the relatively high amount of NOx and CO Simulations did not support the PAH formation under given conditions

28. Folie 28 Vortragstitel 28 Thanks you for your attention Acknowledgments Part of this work was performed within the “ ISP-1” project, coordinated by SNECMA, and supported by the European Union within the 7th Framework Program for Research & Technology. (Grant agreement N° 218849.) Lots of thanks to Dr. Eric L. Petersen for the sent experimental data

29. Folie 29 Vortragstitel 29 Update for H2/CO reactions: new data for reaction rates. Mechanism reduction Full model (47/311) for low pressure CH4 Ignition,laminar flame, concentration profiles NOx mechanism addition New data provoked with the syngas activities, validated on the syngas data