水斗非定常自由水膜流三维贴体数值模拟

本研究采用水斗三维非正交贴体坐标系进行了非定常自由水膜流动的数值解析。对不规则水斗内表面采用三维非正交贴体坐标系下离散点进行拟合,推导了曲面离散点的法向矢量和曲面微元面高斯曲率、平均曲率等几何特征量的计算公式,进而导出流体粒子在运动方向上曲率计算式。在水斗三维贴体坐标系中,还推导了流体粒子在水斗曲面上的运动控制方程。最后对某水轮机水斗内表面非定常自由水膜流进行了数值模拟,得到其非定常水膜流态分布。

NUMERICAL SIMULATION FREE WATER SHEET FLOW ON PELTON BUCKET USING 3-D BODY-FITTED COORDINATE SYSTEM

This paper simulated the unsteady free water sheet flow on bucket surface using 3-D non orthogonal Body-Fitted coordinate system. The irregular bucket surface discrete by high density grids on BFC firstly. By deducing the equations to compute the unit normal vector, Gaussian curvature and mean curvature for bucket grids, the equation of curvature along fluid particle flow direction can be educed. The governing equation of motion for fluid particles moving on bucket was deduced on BFC at the same time. Finally, the water sheet flow patterns on bucket surface were computed by Bucket-Flow-Analysis (BucFlAs) code.