A thermochemical nonequilibrium model of CO2 plasma for studying flow-field properties of the spacecraft Mars Pathfinder

Thermochemical nonequilibrium phenomena are key factors affecting the numerical simulation results of flow fields of Mars rover. In order to make clear the flow field properties of the Mars Pathfinder, a multi-physics numerical model including the Navier–Stokes equations, 11 species and 59 chemical reactions of CO2 plasma, and a four-temperature thermodynamic nonequilibrium model is established in this study. Numerical simulations on the thermal-chemical nonequilibrium flow fields of the Mars Pathfinder spacecraft are performed. The distributions of flow-field parameters such as temperature, pressure, Mach number, molar fractions of CO and CO2 around the Mars Pathfinder at different altitudes are obtained. It is found that there is a subsonic backflow at the rear of the Mars Pathfinder, resulting in slightly higher temperatures than other areas; after the shoulder, the pressure decreases rapidly; as the altitude decreases, the intensity of chemical reactions decreases, and the thermal-chemical nonequilibrium effects gradually weaken. Based on the chemical kinetic model of CO2 we proposed, the numerical simulation of the nonequilibrium flow field of the Mars Pathfinder spacecraft showed good predictive accuracy and application potential, providing reference value for subsequent studies on the thermal-chemical nonequilibrium effects of the Mars Pathfinder spacecraft.