Abstract: The influence of high temperature gas radiation and nonequilibrium coupling effect on the flow field and aeroheating of the Pathfinder Mars probe entry process is numerically investigated in this paper, by solving three dimensional thermo chemical nonequilibrium Navier Stokes equations with the radiation source term and Martian atmosphere reaction model. The results reveal that: 1) Thermochemical non equilibrium effect is significant during the Mars entry, carbon dioxide is dissociated substantially and thermal nonequilibrium effect can be observed at an altitude as low as 28.5 km. 2) The influence of thermal and chemical nonequilibrium effect are related with surface catalytic characteristics, heat flux on the probe surface under full catalytic condition is 50% higher than that of the non catalytic condition. 3) The carbon monoxide in the flow field will produce strong radiation heating, the proportion of radiation heat flux to convective heat flux is approximately 15%~45% and reaches its peak near the shoulder region. 4) The cooling effect of the gas radiation effect would lead to a reduction of the shockwave standoff distance, and the radiative heat flux obtained by the coupled method is decreased by about 12%~25% compared to the uncoupled method.

Key words: Gas radiation, Nonequlibrium, Martian atmosphere, Aeroheating