Modeling Analysis of an Actively Cooled Scramjet Combustor Under Different Kerosene/Air Ratios

Improved delayed detached Eddy simulation (IDDES) modeling based on a developed skeletal combustion mechanism of kerosene/air is conducted for a full-scale actively cooled scramjet combustor under two different global equivalence ratios. A reformulated partially stirred reactor (PaSR) is proposed to adapt it for high mesh resolution. A skeletal mechanism consisting of only 28 species and 92 reactions is reduced for the kerosene combustion modeling. A one-dimensional solid-gas-liquid coupling method is developed to simulate the active cooling effect. The time-averaged static pressure and wall heat flux profiles are well predicted for both fuel-lean and stoichiometric cases. The supersonic flow, mixing, and combustion characteristics under the two fuel/air ratios are quantitatively compared based on the efficiency indices, Takeno Flame Index, and the correlation statistics between heat release rate and mixture fraction. The vorticity and its evolution are analyzed through the five source terms for the two cases. The turbulence-chemistry interaction is then analyzed by the aid of numerous quantitative indices, such as Damkohler number, PaSR coefficient, and scalar dissipation rate, as well as their correlation statistics to identify the main combustion modes in the scramjet combustor.