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.