叶片包角对中比转速泵流场及水力振动的影响分析

ANALYSIS ON THE INFLUENCE OF BLADE WRAP ANGLE ON FLOW FIELD AND HYDRAULIC VIBRATION OF MEDIUM-HIGH SPECIFIC SPEED PUMP

以1台比转速为103的中比转速离心泵为例进行了叶片包角对离心泵水力振动影响的分析,分别采取116°、122°和128°的叶片包角进行不同工况下离心泵外特征的研究。通过电脑模拟仿真分别测定了3种情况下叶轮流道、蜗壳流道内监测点的压力脉动特性,并绘制了压力脉动频域分布图,最终得出以下结论:中比转速离心泵的最佳叶片包角为122°,在这个角度下,中比转速离心泵可以实现扬程与效率最高,并且最佳效率点向大流量方向延伸,叶轮流道内的压力脉动与叶片包角大小成反比,压力脉动幅值与叶片包角大小成正比;蜗壳内压力随着叶片包角增大而增大,但蜗壳内各监测点的压力脉动幅值变化规律并不相同,既有随叶片包角的增大而增大的现象,也有随叶片包角的增大而减小的现象。综合各项因素整体来看,增大叶片包角可以减小中比转速离心泵的水力振动。

In this paper,the influence of blade wrap angle on the hydraulic vibration of a centrifugal pump with a specific speed of 103 was analyzed.Three different blade wrap angles of 116°,122°and 128°were adopted to study the external characteristics of the centrifugal pump under different working conditions.Through computer simulation,the pressure fluctuation characteristics of the monitoring points in the impeller passage and volute passage under three conditions were measured,and the frequency domain distribution diagram of pressure fluctuation was drawn.Finally,the following conclusions were drawn:the optimal blade wrap angle of the medium-high specific speed centrifugal pump is 122°and under this angle,the medium-high specific speed centrifugal pump can achieve the highest head and efficiency,and the optimal efficiency point is in the direction of the pump when the flow direction is extended;the pressure fluctuation in the impeller passage is inversely proportional to the blade wrap angle,and the pressure fluctuation amplitude is directly proportional to the blade wrap angle;the pressure in the volute increases with the increase of the blade wrap angle,but the variation law of the pressure value at each monitoring point in the volute is not the same,and the pressure fluctuation amplitude at each monitoring point in the internal volute increases with the increase of the blade wrap angle as well as with the increase of the blade wrap angle;it decreases with the increase of blade wrap angle.On the whole,increasing the blade wrap angle can reduce the hydraulic vibration of centrifugal pump with medium-high specific speed.