Finite rate chemistry effects upon convective and radiative heating of an atmospheric entry vehicle

A mathematical model of the aerothermochemical environment along the stagnation line of a planetary return spacecraft using an ablative thermal protection system was developed and solved for conditions typical of atmospheric entry from planetary missions. The model was designed to predict viscous, reactive and radiative coupled shock layer structure and the resulting body heating rates. The analysis included flow field coupling with the ablator surface, binary diffusion, coupled line and continuum radiation and equilibrium or finite rate chemistry effects. The gas model used includes thermodynamic, transport, kinetic and radiative properties of air and ablation product species, including 19 chemical species and 16 chemical reactions. Specifically, the impact of nonequilibrium chemistry effects upon stagnation line shock layer structure and body heating rates was investigated. It was also concluded that, for the flight conditions considered, finite-rate chemistry effects are significant since both shock layer structure and body heating rates are markedly different from those predicted by chemical equilibrium analyses.