Modeling of heat transfer attenuation by ablative gases during the stardust reentry

Modern space vehicles designed for planetary exploration use ablative materials to protect the payload against the high heating environment experienced during reentry. To properly model and predict the aerothermal environment of the vehicle, it is imperative to account for the gases produced by ablation processes. The present study aims to examine the effects of the blowing of ablation gas in the outer flow field. Using six points on the Stardust entry trajectory at the beginning of the continuumregime, from 81 to 69 km, the various components of the heat flux are compared to air-only solutions. Although an additional component of the heat flux is introduced by mass diffusion, this additional term is mainly balanced by the fact that the translational-rotational component of the heat flux, the main contributor, is greatly reduced. Although a displacement of the shock is observed, it is believed that themost prominent effects are caused by a modification of the chemical composition of the boundary layer, which reduces the gas-phase thermal conductivity.