超声速欠膨胀冲击射流的数值模拟

Numerical simulation under-expanded supersonic impinging jet

关键词:  超声速射流  轴对称射流  有限体积法  非结构网格  湍流模型  数学仿真

Key words:  Supersonic jet flow  Axisymmetric jet  Finite volume method  Unstructured mesh  Turbulence model  Mathematical simulation

摘要:

利用有限体积法对轴对称可压缩的N S方程进行离散 ,对喷嘴的超声速垂直冲击射流进行了数值模拟。网格的划分采用非结构性网格 ,湍流模型为S A湍流模型 ,在近壁处采用壁面函数进行修正。分别计算压比为3和 4的超声速欠膨胀垂直冲击射流 ,得到详细的波系结构 ,激波形状和位置与实验相吻合。大压比下 ,壁面上冲击中心区域压力相对低 ,分布较平坦 ,压力最大点所在位置偏离中心冲击点 ,并且在近壁处有回流

Abstract:

Supersonic impinging jet was predicted by axisymmetric compressible Navier Stokes equations. A finite volume method with unstructured meshes and S A turbulence model were employed in the calculation. The computation was processed for under expanded supersonic impinging jet under pressure ratio 3 and 4 separately. The wave patterns were shown. The numerical results are in good agreement with experimental data. For higher pressure ratio, the pressure of the impinging region on the plate is lower and keep the same nearly along the radius direction. The position of the maxim pressure shifts from the impinging point. The reverse secondary flow occurs near the solid boundary.