Abstract: To study the impact and thermal effect of the takeoff vacuum exhaust plume to the celestial probe separation，the Computational Fluid Dynamics - Direct Simulation Monte Carlo (CFD-DSMC) coupled model is used to simulate the taper deflector vacuum exhaust plume flow filed. The species transportation model is used to calculate the three-dimensional continuous flow. The local Knudsen is obtained，which is used to distinguish the continuous flow and discrete flow. The Direct Monte Carlo method (DSMC) based on molecular dynamics is used to simulate the discrete flow filed. The Variable Soft Sphere (VSS) model and Larsen and Borgnakke model are used to calculate the molecular energy transfer of the discrete flow. By the contrast of the calculated results and the experimental data，the reliability of the computation method is proved. The results show that，the lateral disturbance moment of A probe is 62N·m. The maximum pressure at the bottom is 100Pa，and the maximum heat flux is 100kW/m2. The lateral disturbance moment of B probe is 558N·m. The maximum surface pressure is 8kPa，and the maximum heat flux is 600kW/m2.The shock waves have been removed from the interior of the nozzle when the nozzle and the deflector top surface distance is 400mm.

Key words: CFD-DSMC coupled method；Vacuum exhaust plume； Celestial probe takeoff；Impact and thermal effect

摘要： 为研究地外天体起飞真空羽流对探测器分离产生的力热扰动，使用计算流体力学-直接模拟蒙特卡洛(CFD-DSMC)耦合计算模型对锥面导流的真空羽流场进行了计算。采用组分输运模型计算三维连续流场，并获取当地的克努森数作为判断连续流和离散流的依据。使用基于分子动力学的直接模拟蒙特卡洛方法(DSMC)计算离散流场，采用可变软球(VSS)碰撞模型和Larsen and Borgnakke传能模型计算离散流分子间的能量传递，将计算结果与试验进行了对比，验证了计算方法的可靠性。研究结果表明，A器受到的侧向干扰力矩为62N·m，底部受到的最大压力为100Pa，最大热流密度为100kW/m2；B器受到的侧向干扰力矩为558 N·m，表面最大压力为8kPa，最大热流密度为600kW/m2，喷口与导流装置顶面距离为400mm时，激波已移出喷管内部。

关键词: 计算流体力学-直接模拟蒙特卡洛耦合方法；真空羽流；地外天体起飞；力热效应