论文部分内容阅读
准确模拟羽流流场是合理评估空间推力器真空羽流效应的基础。因羽流流场同时包含连续和稀薄两种流动机理,通常采用解耦方式的Navier-Stokes(N-S)方程和直接模拟蒙特卡罗(DSMC)混合方法对其进行模拟。为保证解耦N-S/DSMC方法应用于羽流计算时的准确性并尽量提高其计算效率,对计算中的DSMC入口和喷管壁面等边界条件设置问题开展了研究。通过与文献中低总压工况的羽流试验数据比较,确定了合理设置DSMC入口边界位置、壁面反射类型、壁温等边界条件的方法。针对将此方法应用于实际推力器工况计算时效率过低的问题,通过多种数值试验,表明从喷管出口处开始沿KnGL为0.05的等值线作为DSMC入口界面可同时保证仿真精度和较高的计算效率;并证明实际工况下壁温设置对羽流场仿真结果影响不大。
Accurately simulating the plume flow field is the basis for a reasonable assessment of the vacuum plume effect of a space thruster. Due to the fact that the plume flow field contains both continuous and lean flow mechanisms, the decoupled Navier-Stokes (N-S) equation and the Direct Simulation Monte Carlo (DSMC) hybrid method are usually used to simulate the flow field. In order to ensure the accuracy of the decoupled N-S / DSMC method applied to plume calculation and maximize its computational efficiency, the boundary conditions such as DSMC inlet and nozzle wall in calculation were studied. By comparing with the plume test data in the low total pressure condition in the literature, the method of setting the boundary conditions such as DSMC entrance boundary, wall reflection type and wall temperature is determined. Aiming at the problem of too low efficiency when applying this method to actual thrusters’ working condition, through numerical experiments, it is shown that the contour along the KnGL 0.05 as the entrance of DSMC can guarantee the simulation accuracy and Higher computational efficiency. It is also proved that the wall temperature setting has little effect on the simulation results of plume flow field under the actual conditions.