登月舱尺度陨石坑对羽流-月表相互作用影响的数值研究

Numerical study on effects of a module-scale crater on lunar plume-surface interaction

登月舱着陆期间,陨石坑和其他复杂地形可能会加剧发动机羽流引起的月尘扩散,给探月任务带来干扰和威胁.本文采用direct simulationMonteCarlo(DSMC)方法,研究了嫦娥五号发动机羽流与登月舱尺度陨石坑的相互作用.结果表明,陡峭陨石坑显著改变了近场流动结构,在喷管下方形成明显的回流区.回流区增加了坑壁的风化层侵蚀,将月尘吹入喷管,容易对发动机等设备造成结构损坏。同时,随着陨石坑变陡,羽流被陨石坑所偏转的角度明显增加,从而显著增加了登月舱受到的气动力和气动热;最大扬尘角也显著增大,严重干扰了着陆能见度.对于比较平坦的陨石坑,虽然羽流偏转和扬尘的角度较小,但根据Roberts侵蚀模型计算的总侵蚀通量较大,也意味着对登月舱的严重威胁。这些结果揭示了登月舱尺度陨石坑对羽流-月表相互作用的显著影响,为预测和减轻复杂地形对探月任务的威胁提供了有效参考.

During lunar landings,impact craters and other complex terrains may intensify dust dispersion produced by plume-surface interaction,posing disturbances and threats to lunar modules.This study investigates the interaction between rocket plume of the Chang'E-5 module and a module-scale crater using the direct simulation Monte Carlo method.The results show that a steep crater significantly changes near-field flow structures,leading to the formation of a large recirculation bubble beneath the nozzle.The recirculation bubble increases regolith erosion on the crater wall and entrains dust particles into the nozzle,which can cause severe damage to the engine and other devices.Meanwhile,as the crater steepens,the deflection angle of the gas flow significantly increases,elevating pressure and heat flux on the module surface.The maximum inclination angle of lunar dust also increases,seriously blocking the landing visibility.For less steep craters,although the plume deflection and dust dispersion are less severe,the total erosion flux is higher according to Roberts erosion model,implying more damage to the module.This study reveals the significant effects of a module-scale crater on the lunar plume-surface interaction and can serve as a reference to predict and mitigate threats of extreme terrains to lunar missions.