低比转数离心泵叶轮内的流动机理和叶轮设计

Flow Mechanism inside the Impeller of a Centrifugal Pump with Low Specific Speed and Design of the Impeller

通过分析得出影响低比转数离心泵效率的主要原因是在叶轮出口存在二次流、边界层的分离等引起的射流尾迹结构 ,提出了改进的方法。提出叶轮设计方法 :加大叶轮出口宽度 ,增大泵体喉部面积 ,采用较大的叶片出口安放角、较大的叶片包角 ,叶片的线型前部采用较小曲率半径 ,后部采用较大的曲率半径。

In this paper, the influences on the efficiency of a centrifugal pump with low specific speed was analysed and it showed that the second flow, boundary layer separation, and the jet wake structure near the impeller outlet were the key factors influencing efficiency of the centrifugal pump. The theoretical analysis and engineering application indicated that a higher efficiency and better performance could be achieved if a bigger impeller width, bigger throat area of pump casing, bigger blade outlet angle ,and bigger blade warp angle were adopted, as well as a smaller curvature radius in the foreside of the blade and a bigger one in the rearward were taken.