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介绍试验粒子Monte Carlo(test particle Monte Carlo,TPMC)方法,并采用该方法对4种航天器表面出气分子形成的环境散射返回流进行数值模拟.其中,圆球出气表面的计算结果与已有的DSMC(direct simulation Monte Carlo)结果一致,验证了方法的正确性.此外,对不同出气和来流条件下圆形平板、凸半球和凹半球3种航天器简化表面出气分子形成的环境散射返回流进行计算,结果表明:出气表面外形是影响返回通量比的一个重要因素;圆形平板和凹半球出气表面的返回通量比远大于凸半球表面的;凹半球表面的出气分子会直接和出气表面碰撞形成直接流污染,且其量级远大于返回流污染.因此,在航天器设计中尽可能使用凸形表面作为敏感的出气表面可以有效降低出气分子污染.
The experimental particle Monte Carlo (TPMC) method is introduced and the numerical simulation of the environmental scattering return flow formed by the gas molecules on the four kinds of spacecraft surfaces is carried out. The calculated results of the spherical gas exit surface are similar to those of the existing DSMC (direct simulation Monte Carlo) results verify the correctness of the method.Furthermore, for the three kinds of spacecraft with different outburst and inflow conditions, three types of spacecraft such as circular slabs, convex hemispheres and concave hemispheres, The results show that the shape of the outlet surface is an important factor that affects the ratio of the return flux. The return flux ratio of the exit surface of the circular plate and the concave hemisphere is much larger than that of the surface of the convex hemisphere. Surface collision creates direct flow pollution, and its magnitude is much larger than that of return flow.Therefore, the use of a convex surface as a sensitive outlet surface in spacecraft design can effectively reduce the molecular contamination of the gas.