通过探讨主流对壁面流动特性的影响 ,研究三维流动侧向压力梯度产生的边界层内二次流动 ,求解旋转正交曲线坐标系下的边界层方程 ,理论推导出考虑旋转效应的三维分离流动判别准则 ,该判别准则包含了壁面与轴向间夹角的影响 ,根据主流参数的变化判断流动是否发生分离。应用推导出的判别准则研究了旋转角速度、叶片与轴向夹角变化等对叶轮机械内部分离流动的影响 By discussing the influence of the mainstream on the flow characteristics of the wall, the secondary flow in the boundary layer caused by the three-dimensional flow lateral pressure gradient is studied and the boundary layer equation in the rotation orthogonal coordinate system is solved. The three-dimensional flow separation considering the rotation effect is deduced theoretically Criterion, which includes the influence of the included angle between the wall and the axial direction. According to the change of the mainstream parameters, it is determined whether the flow separation occurs. The discriminant criterion derived from this paper is used to study the influence of the rotation angular velocity, the variation of the included angle between the blades and the axial direction on the internal flow in the impeller