Abstract: 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.

Key words: blade wrap angle, centrifugal pump with medium-high specific speed, numerical simulation, hydraulic vibration, pressure fluctuation