一种基于双重空间网格结合的高效DSMC实现方法  

High-efficiency DSMC implement method based on combination of dual spatial grids

作　　者：杜松蔚 王学德[1] DU Songwei;WANG Xuede(School of Energy and Power Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]南京理工大学能源与动力工程学院,南京210094

出　　处：《航空动力学报》2022年第9期1846-1854,共9页Journal of Aerospace Power

基　　金：基础加强重点研究项目(2020-JCJQ-ZD-111)。

摘　　要：基于双重空间网格结合策略,发展了一种高效率的贴体DSMC(direct simulation Monte Carlo)方法。通过将仿真分子在物理空间结构网格的位置坐标映射于计算空间的直角网格中,并在计算空间中完成分子所属网格单元的定位以及分子与边界是否发生作用的判断,从而结合结构网格的贴体性和直角网格的高效率计算的优点,提高DSMC方法的贴体性和计算效率。基于双重空间网格结合策略,通过直接映射和间接映射法分别建立DSMC程序,对微尺度收缩扩张喷管气体流动和超声速圆柱绕流进行模拟。数值结果表明:两种方法均很好地模拟出微喷管因尺度缩小导致的黏性效应和速度滑移现象以及超声速圆柱绕流发生的激波现象,具备有效性。与传统结构网格方法对比,两种方法的计算效率平均分别提高了3.85倍和2.85倍,具备高效性。Based on the combination strategy of dual spatial grids, a high-efficiency bodyfitting DSMC(direct simulation Monte Carlo)method was developed. By mapping the coordinate of the simulated molecule in structural grid in the physical space to the Cartesian grid in the calculation space, and by completing the location of the grid unit to which the molecule belongs and the judgment of whether the molecule and the boundary are interacting in the calculation space,the body-fitness and computational efficiency of the DSMC method were both improved,in combination with the advantages of the body-fitness of the structured grid and the high-efficiency calculation of the Cartesian grid. Based on the combination strategy of dual spatial grids,DSMC programs were established through direct and indirect mapping methods to simulate the gas flow through the microscale contraction expansion nozzle and the supersonic flow past circular cylinder. Numerical results showed that the two methods were effective in simulating the viscous effect and the velocity slip phenomenon due to the shrinkage of the micro nozzle and the shock wave phenomenon caused by the supersonic flow past circular cylinder,demonstrating the effectiveness of the methods. Compared with the traditional structural grid method,the calculation efficiency of the two methods was respectively increased by 3. 85 times and 2. 85 times on average,showing the high efficiency of the methods.

关 键 词：效率 贴体 直接模拟蒙特卡洛 双重空间网格 微喷管 圆柱绕流 

分 类 号：V448.2[航空宇航科学与技术—飞行器设计]