叶片外换热计算程序STAN5收敛性改进

Convergence Improvement of Blade External Heat Transfer Program STAN5

涡轮叶片外换热计算程序STAN5,采用Patankar-Spalding方法求解可压缩边界层微分方程,获得流动及温度边界层内的参数分布,进而得到叶片表面的外换热系数分布。本文分析了STAN5程序的求解方法,研究了程序在外流场存在较强逆压梯度时出现计算不收敛及错误收敛等现象的机理,并对程序进行了两点改进:修正了逆压梯度下边界层内部速度分布,建立了边界层内部沿流向的网格分布与主流压力梯度间的联系。改进后的程序有效地避免了计算发散等问题。

The STAN5 has been widely used for turbine blade external heat transfer calculation. Through solving the compressible boundary layer differential equations with Patankar-Spalding, the distribution of parameters, like velocity and temperature, inside the boundary layer can be gained. And then the distribution of external heat transfer coefficient of turbine blade can be gotten. The numerical methods of STAN5 are discussed. Two improvements have been made according to the non-convergence and the non-reason- able convergence problems of the program operating under reverse pressure gradient conditions. One was the modification of the boundary layer velocity distribution. Another was connecting the grid density along the stream line with the main stream pressure gradient. The problem of non-convergence is effectively avoided with these improvements.