用准三元流动分析方法对4个母型叶轮和相应的派生叶轮、一组进出口参数完全相同仅轮盖形状不同的叶轮和一组子午形状完全相同而叶片数目不同的叶轮中相对速度进行了计算，并与级的性能试验结果进行了对比分析研究，得出了叶轮中相对速度分布特点与级性能的某些关系，提出了改进级性能的某些措施。 Quasi-three-element flow analysis method for the four mother-type impeller and the corresponding derivative impeller, a set of import and export parameters are the same only the cover wheel of different shapes and a group of meridian identical shape and the number of blades in different impedances relative speed Calculated and compared with the performance test results of the grade. Some relations between the relative speed distribution characteristics and the grade performance of the impeller are obtained, and some measures to improve the grade performance are put forward.