Effects of Wall Emissivity on Aerodynamic Heating in Scramjets

The effects of the wall emissivity on aerodynamic heating in a scramjet are analyzed. The supersonic turbulent combustion flow including radiation is solved in the framework of a decoupled strategy where the flow field is determined first and the radiation field next. In particular, a finite difference method is used for solving the flow while a DOM (iscrete ordinates method) approach combined with a WSGGM (weighted sum of gray gases) model is implemented for radiative transfer. Supersonic nonreactive turbulent channel flows are examined for a DLR hydrogen fueled scramjet changing parametrically the wall emissivity. The results indicate that the wall radiative heating rises greatly with increasing the wall emissivity. As the wall emissivity rises, the radiative source and total absorption increase, while the incident radiation decreases apparently. Notably, although the radiative heating can reach a significant level, its contribution to the total aerodynamic heating is relatively limited.