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Master's Thesis MASTER'S THESIS Reduced Kinetic Mechanism of Methane Oxidation for Rocket Applications Alan Kong 2015 Master of Science (120 credits) Space Engineering - Space Master Luleå University of Technology Department of Computer Science, Electrical and Space Engineering Reduced Kinetic Mechanism of Methane Oxidation for Rocket Applications Author: External Supervisor: Fa Quan Alan Kong Dr. Victor Zhukov Examiner: Dr. Victoria Barabash A thesis submitted in the partial fulfilment of the requirements for the Joint European Master in Space Science and Technology Lule˚aUniversity of Technology Universit´ePaul Sabatier Toulouse III Department of Computer Science, Facult´edes Sciences et d'Ing´enierie Electrical and Space Engineering D´epartement de Physique Division of Space Technology October 2015 Abstract Methane, which has properties intermediate between hydrogen and kerosene, is a fuel of several developed and designed rocket engines. Detailed kinetic mechanisms of methane oxidation consist of around 200 or more reactions and about 40-50 species. At the current moment CFD simulations with the use of detailed methane mechanisms can be performed only on supercomputers. However, detailed kinetic mechanisms can be reduced, taking the specifics of rocket combustion chambers. The aim of the present project is to develop a reduced kinetic mechanism of methane oxidation suitable for CFD simulations for rocket applications. The main objective of this thesis work will be a skeletal kinetic mechanism of methane oxidation which is optimized for rocket application. A full detailed methane kinetic mechanism was chosen and reduced to form a skeletal mechanism for rocket application. The resultant skeletal mechanism contains 23 species and 49 reactions and were validated with two separate set of experimental data of ignition delay time at pressure of 50 atm. It is also verified with ignition delay time and counterflow flame temperature profile at rocket condition with pressure of 60 bar. The resultant skeletal mechanism was created through the elimination of species and reactions that are not important to the prediction of ignition delay time and temperature in counterflow non-premixed flame. Reaction path analysis and sensitivity analysis were used to reduced the full mechanism. C3,C4 species were found to be insignificant for methane combustion in rocket condition. C2 species and sub-mechanism were considered important to describe fuel rich methane combustion. The skeletal mechanism had a performance increase in computation time of up to 10 times as compared to computation time of the full mechanism. The ignition delay time and temperature profile predicted by the skeletal mechanism are within 5% difference with values predicted by the full mechanism. The resultant skeletal mechanism is attached as Appendix A in this thesis in CHEMKIN format. Acknowledgements This master thesis work was conducted at the Deutsches Zentrum f¨urLuft- und Raumfahrt (DLR), Institute of Space Propulsion, Lampoldshausen, Germany. The master thesis was carried out in fulfillment of the requirements for the Joint European Master in Space Science and Technology (SpaceMaster) program. This work was done under the supervision of Dr. Victor Zhukov from the Raketenantriebe (Rocket Engine Development) Department. I would like to thank my supervisor and DLR for giving me the opportunity to conduct my master thesis at DLR Lampoldshausen. Special thanks goes to Dr. Zhukov for providing me guidance, feedback and time to answer my questions on the topic of chemical kinetics. I would like to thank my LTU examinar, Dr Victoria Barabash who is always helpful in answering questions on the bureaucratic and administrative matter regarding the master thesis and also for giving tips on how to go about completing the master thesis. I would also like to thank Anette Brandstrom and Maria Winneb¨ack, the two lovely and extremely helpful administrative staff at LTU Kiruna Rymdcampus who were always attending our questions and taking good care of me and my fellow SpaceMaster students in Kiruna. I would also like to thank Sven Mollin for the discussion on the SpaceMaster program, its history and what the future holds for this program. I was also very grateful for his help in providing the contact for my internship in the Satellite Research Center at the Nanyang Technological University in Singapore. I would also like to thank my colleagues in the Raketenantriebe Department as well as the M¨ockm¨uhlWohnheimers for making my time in DLR Lampoldshausen really enjoyable with all the parties, schnitzel challenges, DLR Cup and Motorman Run. Special thanks also goes to Lionel, Scott, Bombardieri, Sam, Jeremy Wang and Chan, Sebastian, Baskar and Sukruth for the wonderful atmosphere living at Wohnheim. I would like to also thank all my fellow SpaceMaster friends, Ferran, Nick, Steffen, Jeremy, Toby, Garima, Manisha, Martin, Chuck, Yo, Sam, Tommy and many more who had made these two years one of the best years of my life. The auroras, epic skiing and snowboarding trips, large dinner parties we have and the sauna session were some of the fond memories that I will cherish and carry with me wherever I go. I would also like to thank all my LTU peers from Ringv¨agen,Oscar, Emil, Joakim, Pappis for making my second semester in Kiruna just as enjoyable as the first with the house party, the celebration for Santa Lucia and the awesome pool session every Friday at the Kiruna Bad House. Last but not least, I would like to thank my family for their support in giving me the opportunity to participate in this master program. ii Contents Abstract i Acknowledgements ii Contents iii List of Figuresv List of Tables vi Nomenclature vii 1 Introduction1 1.1 Methane: An Alternative Choice For Rocket Propellant............1 1.2 A Brief Introduction to Chemical Liquid Propellant Rocket Engine......2 1.2.1 LPRE Combustion Chamber.......................3 1.2.2 Determining the Performance of LPRE.................4 1.2.3 Operating Condition in Rocket Combustion Chamber.........5 1.3 Problem definition.................................7 1.3.1 Combustion Modelling in Rocket Engine.................7 1.3.2 Challenges of Combustion Modelling in Rocket Engine.........7 1.4 Thesis Motivations.................................8 2 Literature Review 10 2.1 Focus of Literature Review............................ 10 2.2 Chemical Kinetics................................. 10 2.3 Thermodynamics Properties............................ 13 2.4 Transport Properties................................ 13 2.4.1 Mixture-Averaged Transport Properties................. 16 2.5 Choice of kinetic mechanism for reductions................... 17 3 Reduction Methods 18 3.1 Choice of Simulations and Initial Condition................... 18 3.2 PSR and Batch Reactor.............................. 18 3.3 Counterflow Non-Premixed Laminar Flame................... 22 3.4 Reductions Techniques............................... 26 3.4.1 Reaction Path Analysis.......................... 26 3.4.2 Sensitivity Analysis............................ 27 iii Contents iv 3.5 Cantera, An Objected Oriented Software for Chemical Kinetics, Thermodynamics and Transport Problems.............................. 28 3.6 Summary of the Reduction Procedure...................... 29 4 Simulation and Analysis 31 4.1 Reaction Path Analysis.............................. 31 4.1.1 0D Reaction Path Analysis........................ 31 4.1.2 1D Reaction Path Analysis........................ 33 4.1.3 Conclusion of Reaction Path Analysis.................. 37 4.2 Sensitivity Analysis................................. 38 4.2.1 0D Sensitivity Analysis.......................... 39 4.2.2 1D Sensitivity Analysis.......................... 40 4.2.3 Conclusion of Sensitivity Analysis.................... 42 4.3 Final Skeletal Kinetic Mechanism......................... 42 5 Validation, Verification and Performance 44 5.1 Validation With Ignition Delay Time....................... 44 5.1.1 Validation With Past Experiments.................... 44 5.1.2 Verification With Rocket Condition................... 45 5.2 Verification against Temperature Profile From Counterflow Flame Simulation 46 5.3 Performance Of Final Skeletal Mechanism.................... 47 6 Summary, Conclusions and Future Work 48 6.1 Conclusions..................................... 48 6.2 Future Work and Outlook............................. 48 Bibliography 50 A Final Skeletal Mechanism, CHEMKIN Format 54 B Major Species Profiles 57 List of Figures 1.1 Theoretical Vacuum Isp of Various Propellant [12]...............1 1.2 Schematics of a Gas Generator Rocket Engine [35]...............3 1.3 Typical Stress Load and Temperature Profile Near Chamber Wall [35]....4 1.4 Parameters In A Rocket Combustion Chamber [35]...............4 1.5 Methane Rocket Engine Demonstrator Unit by Aerojet [16]..........6 3.1 PSR with H radical ignitor............................ 20 3.2 Major Species Mole Fractions for PSR...................... 20 3.3 Batch Reactor at Constant Pressure of 60 bar.................. 21 3.4 Experimental imaging of gaseous hydrogen and liquid oxygen in single coaxial fuel oxidizer injector (TOP) and the idealized counterflow flame problem in 1D (BOTTOM) by Juniper et al [17]....................... 24 3.5 1D Counterflow Flame Structure......................... 25 3.6 Temperature and heat release profile of counterflow flame with fuel/oxidizer inlet T = 300K, a = 9400s−1 and p = 60 atm. normal line: T profile, dashed line: Q profile, dots: positions where Sr are calculated.............. 28 3.7 Reduction
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