火星大气模型参数对MSL气动特性的影响

火星大气与地球大气截然不同，飞行器在进入火星时气动特性不同于地球再入. 大气模型的差异主要表现为气体组份、密度和温度等物理参数. 针对火星进入器MSL在进入-下降-着陆过程中的高超声速进入段，利用三维并行程序求解耦合真实气体模型的流体动力学Navier-Stokes方程，分析MSL进入火星大气时大气模型参数对进入器气动特性的影响. 结果表明，通过与海盗号飞行数据的对比，验证了所采用的火星气体模型和计算方法，且其与NASA的 LAURA代码气动特性计算结果也较为一致；大气模型气体性质，即CO₂环境对进入器阻力系数和俯仰力矩系数影响较大，利用空气得到的计算和实验数据必须考虑CO₂效应；密度增大促进了化学非平衡效应，但对进入器气动特性基本没有影响；温度升高大大增强了化学非平衡效应，而对进入器气动特性影响较小. 

Impact of Martian Atmosphere Model Parameters on Aerodynamic Characteristics of Mars Science Laboratory

The difference between Martian atmosphere and Earth atmosphere results in the different flow field and property around the entry vehicles, and the possible change of aerodynamic characteristic on account of chemical non-equilibrium will differ from that in Earth re-entry process. The differences between Martian and Earth atmosphere include species, density and temperature. Three-dimensional Navier-Stokes equations coupling real gas model are solved by a parallel code to analyze the change of aerodynamic characteristic of Mars Science Laboratory (MSL) introduced by CO₂ effect as well as the uncertainty of density and temperature in hypersonic entry phase of Entry-Descending-Landing procedure when MSL entering the Martian atmosphere. The results show that the computational data of Viking based on current Martian atmosphere model and numerical methods has a good agreement with both the flight data and LAURA results. Gas species in the model, which are mainly CO₂ for Mars, have a great influence on the drag and pitching moment coefficients compared to the air model of Earth, so CO₂ correction should be considered while the aerodynamic data is derived from air. Increase of the density in atmosphere model enhances chemical non-equilibrium effect, but produces no distinctness for aerodynamic characteristic; increase of the temperature improves chemical non-equilibrium effect greatly, and has a small influence on aerodynamic characteristic.