叶片包角对中比转速离心泵水力振动的影响研究

Study on the Influence of Blade Wrap Angle on Hydraulic Vibration of Centrifugal Pump

为了研究叶片包角对中比转速离心泵水力振动的影响,以一台比转速为103的中比转速离心泵为研究对象,探讨叶片包角分别为116°、122°、128°的3种离心泵在不同的流量工况下的外特性特征,设计流量下叶轮流道、蜗壳流道内监测点的压力脉动特性。研究结果表明:存在一个最佳的叶片包角122°使中比转速离心泵的扬程和效率最高,且最佳效率点向大流量点偏移;叶轮流道内各监测点的压力脉动随叶片包角的增大而逐渐降低,而各压力脉动幅值随叶片包角的增大而逐渐增大;蜗壳螺旋段内的压力脉动值沿流体流动方向逐渐减弱;随着叶片包角的增加,蜗壳流道内监测点的压力值逐渐增大,隔舌监测点和出口处监测点的压力脉动幅值也同步增大,而蜗壳螺旋段内监测点的压力脉动幅值逐渐减小。综合考虑适当地增大叶片包角可以减小离心泵的水力振动。

In order to study the influence of blade wrap angle on the hydraulic vibration of medium specific speed centrifugal pump,a medium specific speed centrifugal pump with a specific speed of 103 is taken as the research object.The characteristics under different flow conditions,and the pressure pulsation characteristics at the monitoring points in impeller flow passage and volute flow passage at design flow condition of three kinds of centrifugal pumps with blade wrap angles of 116°,122°and 128°respectively are analyzed.The research results show that,(a)there is an optimal blade wrap angle of 122°to maximize the lift and efficiency of pump and shift the optimal efficiency point to a large flow point;(b)with the increase of blade wrap angle,the pressure pulsation in impeller flow path gradually decreases and the amplitude of each pressure pulsation gradually increases;(c)the pressure pulsation value in the spiral section of volute gradually weakens along the direction of fluid flow;and(d)with the increase of blade wrap angle,the pressure value in volute flow channel gradually increases,the pressure pulsation amplitude in tongue and outlet also increases synchronously,but the amplitude of pressure pulsation in spiral section of volute gradually decreases.From a comprehensive perspective,properly increasing blade wrap angle can reduce the hydraulic vibration of centrifugal pump.