摘要
针对火星和地球大气分子热力学和化学行为的差异性,采用理论分析和数值模拟两种手段,研究探测器进入过程高超声速流动的分子振动激发、离解反应及热力学和化学非平衡等真实气体效应,获得不同气体模型条件下的高超声速气动加热规律,探究引起地火差异的根本原因。分析认为,探测器进入火星大气层的稀薄气体效应明显;激波层内发生CO_2气体为主的大规模离解,在极高温环境下O_2和CO也将离解;沿进入轨道的高超声速流动基本处于化学非平衡但热力学平衡状态;激波层内能量储存和分配模式因分子振动激发和化学反应而改变,分子振动激发会增强气动加热量,但均介于化学反应模型的完全非催化和完全催化壁结果之间;相同来流条件下CO_2介质高超声速气动加热强于空气介质,但真实的火星进入热载荷因大气稀薄而弱于地球再入环境。相关研究为我国未来火星探测器热防护系统设计提供技术支持。
Based on the distinction of the thermal and chemical behaviors between the Martian gas and air,hypersonic real-gas effects,including the vibrational excitation,dissociation,and thermal and chemical non-equilibrium,are firstly analyzed by means of the theoretical analysis and numerical simulation. The aerodynamic heating rates are thereafter obtained with the different gas models so as to investigate the essential distinction between the Mars and Earth. The analysis results show that the rarified effect is remarkable at the early high-altitude entry stage; a large amount of the post-shock CO_2 dissociates while O_2 and CO only do at higher temperature; the hypersonic flowfield exhibits strong chemical nonequilibrium but thermal equilibrium during the whole entry process; the vibrational excitation and chemical reactions alter the disposition of the energies and the heat flux with thermally perfect gas model is higher than that with calorically perfect gas model,both of which are within chemical results with the non-and fully catalytic conditions; the Martian aerodynamic heating is more severe than that of air,but the thermal load for the Mars entry process is weaker than that for the Earth reentry process due to the rarefied Martian atmosphere. The current investigation can provide the technical support for the thermal protection system design of the future Mars entry capsules.
作者
杨肖峰
国义军
唐伟
桂业伟
杜雁霞
YANG Xiao-feng;GUO Yi-jun;TANG Wei;GUI Ye-wei;DU Yan-xia(State Key Laboratory of Aerodynamics,China Aerodynamics Research and Development Center,Mianyang 621000,China)
出处
《宇航学报》
EI
CAS
CSCD
北大核心
2018年第9期959-967,共9页
Journal of Astronautics
基金
国家自然科学基金(11702311
11472295)
