Influence of surface catalysis on coupled aerodynamic heating for Mars entries

Abstract

The integral simulation of aerodynamic heating for Mars entries encounters great challenges due to exceptional and complex high-temperature real-gas effect and gas-solid thermochemistry effect. Coupling computation strategy for hypersonic nonequilibrium aerodynamic heating and in-depth heat transfer was established in order to accurately predict the thermal environment of Mars entry vehicles. Coupling analysis for the heatshield of Mars entry vehicle was then performed to reveal the mechanism how the nonequilibrium thermochemistry affects the coupled aerodynamic heating. Computation results show that both the convection and diffusion heatflux from non-equilibrium flow field have large influences on the total aerodynamic heating rate; the diffusion component contributes the foremost to the overall aerodynamic heating, especially for that originating from CO2; the current thermal protection structure can effectively prevent the severe thermal load from transferring into the cabin, and the aerodynamic heating and the surface radiation can rapidly get close to thermal equilibrium, accounting for the validation of the radiation equilibrium assumption for uncoupled aerodynamic heating prediction; the heatflux decreases for non- and fully catalytic walls while the finite-rate catalytic heating rises and then drops due to the gas-solid interface thermochemistry effect; the linearity between the surface heatflux and temperature will get weak due to the introduction of diffusion heating induced by the gas-solid interface thermochemistry.