A three-dimensional computational fluid dynamics code is developed for predicting nonequilibrium flowfields over Mars entry probes. The numerical scheme is based on the cell-vertex finite volume method for a prismatic unstructured mesh system. Internal energy excitations and chemical reactions with finite rates are considered by introducing the two-temperature model of Park. Eight chemical species, C, N, O, CO, N2, NO, O2, and CO2, and nine chemical reactions are considered in the calculations. The developed code is verified in terms of prediction of heat flux to the body surface near the stagnation point of a Mars entry probe flying with the velocity of 6 km/s. The calculated heat flux reasonably agree with the calculated result in the past studies.

Aerodynamic coefficients of a reentry bodyin hypersonic flowfiled are calculated by using a three-dimensional flow solver. The high temperature real gas effects, thermal excitations and chemical reactions of air, are accounted for in the calculation. The reasonable agreement between the calculated aerodynamic coefficients and the Apollo AS-202 flight date are obtained. The effects of thermochemical nonequilibrium on the aerodynamic predictions are shown to be non-negligible.