临近空间高超声速空腔几何特性的DSMC研究

DSMC Study on Geometric Characteristics of Hypersonic Cavity in Adjacent Space

为研究稀薄流区域内空腔内流场的流动特性,采用非结构网格直接模拟蒙特卡洛方法(DSMC)对临近空间不同高度下的不同几何形状空腔进行模拟。模拟条件:高度分别为50 km,60 km,70 km,80 km,90 km;空腔的长度与深度之比分别为1,2,3,4,5,6,7,8,9,10;壁面的倾斜角为30°,45°,60°,75°;来流的马赫数分别设置为5,10,15,20。模拟结果表明:不同的几何形状对空腔内的再循环区域有着显著的影响;稀薄流区域内不同高度和速度下,空腔内流场的流动结构会在特定的长深比发生类型转变。此外,研究发现改变空腔壁面的倾斜角度可以消除空腔内的再循环区域;30°以下的角度为适合的倾斜角度。

In order to study the flow characteristics of flow field in the cavity in the rarefied flow region,the direct simulation Monto-Carlo(DSMC)method with unstructured grid was used to simulate different geometrical cavities at different heights in the adjacent space.The cases had different calculation parameters.The height was 50 km,60 km,70 km,80 km and 90 km;the length-to-depth ratio was 1,2,3,4,5,6,7,8,9 and 10;the inclination angle of the wall was 30°,45°,60°and 75°;the Mach number of inflow was 5,10,15 and 20,respectively.The simulation result shows that different geometries had a significant effect on the recirculation area within the cavity.At different heights and velocities in the rarefied flow region,the flow structure of the flow field in the cavity will change in type at a specific aspect ratio.The study shows that it can eliminate the recirculation area in the cavity to change the inclination angle of the cavity wall surface,and the angle below 30°is a suitable inclination angle.