Dynamic Study of Coupled Heavy Hydrocarbon Pyrolysis and Combustion

Hypersonic flight over Mach 5 should be achieved with Supersonic Combustion Ramjet. The regenerative cooling presents the advantage to use the fuel as a coolant, which results in its pyrolysis. Both cooling channel and combustion chamber are studied numerically by coupling the transient phenomena with detailed pyrolysis and combustion chemistry (360 species and 2777 reactions). A Mach 6 flight configuration is chosen to study the impact of fuel mass flow rate on the combustion for equivalence ratio varying from 0.01 to 1. The time characteristics of the phenomena are determined. A higher flow rate provides higher hot gases temperature and faster stabilization time and auto-ignition delay. This impacts positively the flame anchoring. Several analytical laws are proposed for later development of a control strategy. A hysteresis is found because of the heat transfer dynamics. Finally, the combustion mechanism is applied and validated experimentally for kerosene pyrolysis application.