为研究超低地球轨道(ultra-low earth orbit,ULEO)环境气体对离子推进器返流的影响,将粒子网格(particle-in-cell,PIC)法与DSMC(direct simulation Monte Carlo)法相结合,采用可变硬球(variable hard sphere,VHS)模型,建立了稀薄气体与...为研究超低地球轨道(ultra-low earth orbit,ULEO)环境气体对离子推进器返流的影响,将粒子网格(particle-in-cell,PIC)法与DSMC(direct simulation Monte Carlo)法相结合,采用可变硬球(variable hard sphere,VHS)模型,建立了稀薄气体与羽流相互作用的粒子模拟模型,对不同工况下氮气、原子氧与羽流的相互作用进行了仿真分析。结果表明,推进器羽流返流通量的变化与环境气体的来流方向相关,在相同条件下,超低地球轨道原子氧环境中的返流密度约为氮气环境中的85%。展开更多
All long-duration spacecraft in low-earth-orbit are subject to high velocity impacts by meteoroids and space debris. Such impacts are expected to occur at non-normal incidence angles and can cause severe damage to the...All long-duration spacecraft in low-earth-orbit are subject to high velocity impacts by meteoroids and space debris. Such impacts are expected to occur at non-normal incidence angles and can cause severe damage to the spacecraft and its external flight-critical systems and possibly lead to catastrophic failure of the spacecraft. In order to ensure crew safety and proper function of internal and external spacecraft systems, the characteristics of a debris cloud generated by such impacts must be known. An analytical model is therefore developed for the characterization of the penetration and ricochet debris clouds created by the hypervelocity impact of an aluminum spherical projectile on an aluminum plate. This model employs normal and oblique shock wave theory to characterize the penetration and ricochet processes. The prediction results of center-of-mass trajectory and leading velocity of penetration and ricochet debris clouds are obtained and compared with numerical and experimental results in figures.展开更多
文摘为研究超低地球轨道(ultra-low earth orbit,ULEO)环境气体对离子推进器返流的影响,将粒子网格(particle-in-cell,PIC)法与DSMC(direct simulation Monte Carlo)法相结合,采用可变硬球(variable hard sphere,VHS)模型,建立了稀薄气体与羽流相互作用的粒子模拟模型,对不同工况下氮气、原子氧与羽流的相互作用进行了仿真分析。结果表明,推进器羽流返流通量的变化与环境气体的来流方向相关,在相同条件下,超低地球轨道原子氧环境中的返流密度约为氮气环境中的85%。
文摘All long-duration spacecraft in low-earth-orbit are subject to high velocity impacts by meteoroids and space debris. Such impacts are expected to occur at non-normal incidence angles and can cause severe damage to the spacecraft and its external flight-critical systems and possibly lead to catastrophic failure of the spacecraft. In order to ensure crew safety and proper function of internal and external spacecraft systems, the characteristics of a debris cloud generated by such impacts must be known. An analytical model is therefore developed for the characterization of the penetration and ricochet debris clouds created by the hypervelocity impact of an aluminum spherical projectile on an aluminum plate. This model employs normal and oblique shock wave theory to characterize the penetration and ricochet processes. The prediction results of center-of-mass trajectory and leading velocity of penetration and ricochet debris clouds are obtained and compared with numerical and experimental results in figures.
