Material-dependent catalytic recombination modeling for hypersonic flows

A new model to predict catalytic recombination rates of O and N atoms over silica re-entry thermal protection system is reported. The model follows the general approach of Halpern and Rosner, but adds estimates of some key physical mechanism parameters based on realistic surface potentials. This novel feature can therefore produce rate expressions for any surface for which structure is known, Testing the model for N over W, and N and O over SiO2 produces recombination probabilities in good agreement with published measurements at high surface temperature, In the case of N and O over SiO2, the model accounts for surface NO production due to O and N cross recombination.