气固相互作用对吸气式电推进系统进气道性能的影响  

Effects of gas-surface interaction on the inlet performance of an atmosphere-breathing electric propulsion system

作　　者：周靖云 靳旭红 程晓丽[1] 艾邦成[1] ZHOU Jingyun;JIN Xuhong;CHENG Xiaoli;AI Bangcheng(China Academy of Aerospace Aerodynamics,Beijing 100074,China;School of Aerospace Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]中国航天空气动力技术研究院,北京100074 [2]清华大学航天航空学院,北京100084

出　　处：《清华大学学报（自然科学版）》2024年第9期1536-1546,共11页Journal of Tsinghua University(Science and Technology)

基　　金：中国博士后科学基金(2023M741912)。

摘　　要：针对上层大气层吸气式电推进系统进气道设计问题,采用直接模拟Monte Carlo(DSMC)方法对吸气式电推进系统的进气道内流问题进行系统的数值模拟,考虑气固相互作用(GSI)模型对进气道内流特征、进气道收集和压缩性能的影响,并从气体动理论的角度阐明了其作用机理。结果表明:GSI模型对进气道的压缩和收集性能具有巨大的影响,适应系数的降低即GSI中镜面反射比例的升高,能显著提高压缩因子和收集效率,适应系数从1.0降低到0.2使得压缩因子增大7倍多,收集效率增大将近4倍。适应系数的降低能有效增大进气道压缩因子和收集效率的机制是气体分子在内凹型压缩段壁面发生镜面反射之后汇聚通过焦点,进入电离加速段。上层大气层吸气式电推进系统的进气道应该采取几何外形/表面材料相互耦合的设计思路:既采用内凹型压缩段的进气道,更需要通过材料选取或表面加工降低GSI适应系数,使得GSI尽量接近镜面反射。[Objective] The atmosphere-breathing electric propulsion(ABEP)system has become a highly promising candidate for drag compensation in spacecraft operating in very low Earth orbit.To improve the inlet design of ABEP systems,this study performs a comprehensive numerical investigation of gas flows inside the inlet.The primary objective is to gain insight into the effects of the gas-surface interaction(GSI)model on the flow features,compression,and collection performances.[Methods]This paper explores ABEP inlet flows using the direct simulation Monte Carlo(DSMC)method.A typical altitude of 180 km in the upper atmosphere is considered,and four GSI accommodation coefficients(σ=1,0.8,0.5,and 0.2)are selected.The DSMC method simulates gas flows according to the motion of a cluster of simulation particles,where each particle represents a large number of real gas molecules.In the DSMC method,particle motions are computed deterministically,whereas intermolecular collisions are calculated statistically.Each simulation particle travels at a constant velocity until it collides with another simulation particle or a solid surface.In the event of an intermolecular collision,an appropriate molecular collision model is employed to compute post-collision velocities,and in the event of gas-surface collisions,a suitable GSI model is adopted to calculate the molecular velocity after reflection.In this work,the internal energy exchange is modeled using the Larsen-Borgnakke scheme.Further,the intermolecular collision is handled using the variable hard sphere model and the no time counter-collision sampling technique.The simulation is always evaluated as an unsteady flow,and a steady result is obtained as the large-time state of unsteady simulation.After achieving a steady flow,the simulation particles in each cell are sampled for a sufficient duration to decrease statistical scattering.All macroscopic field quantities(such as mass density,velocity,and temperature)and surface quantities(such as surface pressure,shear stress,and heat flux

关 键 词：上层大气层 稀薄气体流动 低密度气体流动 进气道 直接模拟Monte Carlo(DSMC)方法 

分 类 号：V211.25[航空宇航科学与技术—航空宇航推进理论与工程]