气体辐射与流场耦合对火星进入热环境影响

Influence of Coupling of Gas Radiation and Flow Field on Thermal Environment of Mars Entry Vehicle

采用火星大气物理化学模型,求解带辐射源项的三维热化学非平衡N-S方程,对探路者号火星探测器进入过程中的高温流场和热环境进行了数值模拟,分析了气体辐射与非平衡流场耦合效应对流场和热流的影响。结果表明:1)探路者号火星探测器流场热化学非平衡效应显著,CO_(2)气体发生大规模离解,高度低至28.5 km仍存在热力学非平衡效应;2)热力学与化学非平衡效应的影响均与表面催化特性相关,完全催化热流要高于完全非催化热流50%以上;3)高温流场中的CO组分会产生较强的气体辐射加热,辐射热流与对流热流的比值为15%~45%,靠近肩部区域比值最大;4)气体辐射对非平衡流场的冷却效应使激波脱体距离减小;与非耦合方法相比,采用耦合方法得到的辐射热流降低约12%~25%。

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.