大气环境对火星探测器气动特性影响分析  

Influence of Atmosphere Condition on Aerodynamic Characteristics of Mars Probe

作　　者：马洋 张青斌[2] 丰志伟[2] 

机构地区：[1]第二炮兵工程大学动力工程系,西安710025 [2]国防科学技术大学航天科学与工程学院,长沙410073

出　　处：《航天返回与遥感》2016年第2期18-25,共8页Spacecraft Recovery & Remote Sensing

基　　金：第二炮兵工程大学科研基金青年项目(2015QNJJ034)

摘　　要：为了探索火星大气环境与地球大气环境的差异对探测器气动性能的影响,文章以"火星科学实验室"(MSL)为研究对象,采用计算流体力学方法研究开伞阶段MSL在两种大气环境下的气动特性。分析了典型开伞阶段的来流条件,采用克努森数界定是否需要在数值仿真时考虑稀薄气体效应,认为气流满足连续介质假设。数值仿真结果表明,攻角小于20°时两种大气环境下的气动力系数较为接近,反之气动力系数差别较大,并且大部分计算状态下火星大气环境下的气动力系数大于地球大气环境下的气动力系数。马赫数为0.3和2.1时,两种大气环境下的气动力系数差异较大,马赫数为0.9和1.5时气动力系数较为接近。两种大气环境下,气动力系数随攻角的变化趋势大致相同,但随马赫数的变化趋势存在较大差别。典型超声速流场对比分析表明,火星大气的低密度特点会导致激波脱体距离更大、膨胀波束分布更广,进而导致探测器表面压力偏大。研究对于探测器减速着陆研究具有一定的参考意义。To identify the influence of atmospheric condition on aerodynamic characteristics of Mars probe, the aerodynamic characteristics of Mars Science Laboratory（MSL） in the stage of opening parachute under the condition of Mars and Earth atmosphere are researched. The Computational Fluid Dynamics（CFD） is employed to solve the flow field. The continuity of Mars atmosphere at typical simulation altitude is analyzed and the Knudsen number is used as the quantitative criterion for considering rarefied gas effect or not. According to calculating, the Knudsen number is much smaller than the critical value, so the rarefied gas effect can be ignored. Some useful conclusions are obtained from CFD computation. First, when the angle of attack was smaller than 20 degree, the aerodynamic coefficients of MSL acquired under the two atmospheric conditions are approximative. On the contrary, the coefficients are considerably different. Second, the aerodynamic coefficients of MSL acquired in Mars atmosphere are larger than those in Earth atmosphere in most computational cases. Third, when Mach number is 0.3 and 2.1, the difference of aerodynamic characteristics of MSL is obvious, while Mach number is 0.9 and 1.5, the difference is small. Fourth, under Mars and Earth atmospheric conditions, the variation trends of aerodynamic coefficients of MSL along angle of attack are approximately similar, while the variation trends with Mach number are distinct. By contrastive analysis of flow field structure under the two atmospheric conditions, some results are obtained. Because of the low density property in Mars atmosphere, the distance of bow shock is longer, and the distribution of expansion wave is wider, so the surface pressure on probe in Mars atmosphere is higher. The research can supply some references for the study of decelerating and landing on Mars probe.

关 键 词：火星探测 气动减速 火星科学实验室 大气环境 气动特性 深空探测 

分 类 号：V411[航空宇航科学与技术—航空宇航推进理论与工程]