H型叶栅通道流计算网格的改进

Improvement of H-type grid for compressor cascade flow calculation

关键词:  压气机  叶栅流  流场仿真  数值计算  网格生成

Key words:  Air compressor  Cascade flow  Flow field simulation  Numerical calculation  Grid generation

摘要:

提出一种壁面正交、尾迹区网格节点分布逐渐均匀化叶栅通道网格生成方法。为了研究壁面处网格正交性对数值计算结果的影响,推导出壁面附近流动参数一阶导数离散误差与网格线交角的数学关系。采用N S方程分别对平板紊流附面层流和叶栅通道流进行计算分析。结果表明:壁面处网格正交性对附面层内流动计算预测精度影响较大,而对势流区流动影响很小;尾迹区切向网格节点逐渐均匀化分布能更准确计算尾迹区流动。

Abstract:

A new kind of H-type grid generation method was proposed, by which the generated grid lines orthogonally intersect at blade surfaces. The method was successfully applied to grid generation of several types of compressor cascade flow fields. It was also proposed that in blade wake region the grid node distribution along the cascade tangent direction should gradually tend to uniformity and adapt to flow parameter variation in the region. To analyze influence of grid line intersection angle at the wall on calculated results, expression of discrete errors of the derivatives in relation to the angle was deduced. Numerical calculation of a plate turbulent boundary layer and cascade flows were performed. The investigation demonstrates that the intersection angles of grid lines at solid walls have significantly influence on the predicted results in the boundary layer regions; but nearly have no evident influence on the results in the potential regions.