Ablation Studies for a Super-Orbital Reentry Capsule Using a Three-Temperature Model

Abstract

The aerodynamic heating to a super-orbital reentry capsule with ablation heat protection was studied numerically by using thermochemical nonequilibrium full-viscous-shock layer (VSL) equations. A species model composed of 11 air species and 6 carbonic species was used. In the case of the super-orbital reentry, radiative heat flux to the wall cannot be neglected. The intensity of emission spectrum is strongly dependent on rotational, vibrational, electron and electronic temperatures, so that a thermal nonequilibrium analysis is needed to predict these temperatures more accurately. Therefore, a 3-temperature model composed of translational-rotational, vibrational and electron-electronic temperatures was adopted. Stagnation heat fluxes to the wall with and without ablation were calculated at various wall temperatures. Results for the reentry flight conditions at an altitude of 64 km showed that the stagnation heat fluxes with and without ablation are almost equal below a wall temperature of 3,200 K, whereas at wall temperatures over 3,200 K, the stagnation heat flux is reduced owing to significant sublimation of ablation material.