Characterization of the Hydrogen Combustion Process in a Scramjet Engine

In this paper, by using a large eddy simulation, we study the combustion process in the HyShot II scramjet combustor. By conducting a detailed analysis of the mass-fraction distributions of the main species, such as H2 , H2O and the radicals, OH and HO2 , of the mass source terms of these main species, and of the chemical source term of the energy equation, we detect the regions where chemical reactions occur through a diffusion process and the regions where auto-ignition and premixed combustion may develop. The analysis indicates that the combustion process is mainly of diffusive type, along a thin shear layer enveloping the hydrogen plume, whereas, there could be some auto-ignition and/or premixed combustion cores inside the plume.