Reduced Kinetic Mechanism of Methane Oxidation for Rocket Applications

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.Validerat; 20151006 (global_studentproject_submitter