Aeroheating study of hypersonic chemical nonequilibrium flows around a reentry blunt body

Studies on the computational methods for aeroheating are performed based on a hypersonic cylinder flow experiment in German Aerospace Center (DLR). Numerical experiments show that, in addition to decrease the temperature after shock wave and the shock wave stand-off distance, high temperature gas effects can also increase the static pressure after shockwave when compared to the perfect gas results. However, this pressure rise is mainly caused by the variation of the specific heat with temperature, other than by the chemical reactions. The dual-specific-heat pressure relation across the normal shock wave proposed by Fan is proved to be able to predict this pressure rise. Moreover, for this cylinder case with a total temperature of about 11394 K, the ionization reactions would not notably influence the temperature and heat flux results. The wall catalytic effect has little influence on the convective heat flux, while would lead to another mass diffusion heat flux component, and thus largely enhance the total wall heat flux. Finally, it is found that the widely-used method to determine the distance of the first grid point off the wall for aeroheating simulation by the cell Reynolds number based on free stream parameters is not reliable for this cylinder case, and a much denser mesh is needed in order to obtain reliable wall heat flux.