叶片V 型切割对低比转速离心泵压力脉动的影响

Effect of blade V-shaped cutting on pressure pulsation of centrifugal pump with low specific speed

为研究设计工况下叶片V型切割宽度对低比转速离心泵外特性以及压力脉动的影响,以一台比转速ns=67的离心泵为研究对象,在保证叶轮和蜗壳其他几何参数不变的情况下,对叶片出口边进行V型切割,利用N-S方程和RNG k-ε湍流模型对流场进行全三维数值计算。研究结果表明:叶片V型切割宽度对离心泵外特性有显著影响,扬程和效率随着叶片V型切割宽度增大而逐渐降低,但效率下降幅度较小,同时离心泵蜗壳内部和蜗壳出口处的压力也明显下降;各监测点压力脉动具有明显周期性特征,蜗壳隔舌、第Ⅰ断面和蜗壳出口监测点压力脉动幅值随着切割宽度增大而呈现出先减小后增大的趋势,当叶片出口相对切割宽度为33.33%时,离心泵内压力脉动幅值达到最小。

In order to study the influence of the V-shaped cutting width of the blade on the external characteristics and pressure pulsation of the low specific speed centrifugal pump under the design conditions,by taking a centrifugal pump with specific speed of ns=67 as the research object,and under the condition that other geometric parameters of impeller and volute are kept unchanged,V-shaped cutting is carried out on the outlet edge of blade,and full three-dimensional numerical calculation is carried out using N-S equation and RNG k-εturbulence model.The results show that the V-shaped cutting width of the blade has a significant effect on the external characteristics of the centrifugal pump.The head and efficiency decrease gradually with the increase of the V-shaped cutting width of blade,but the decrease amplitude of efficiency is relatively small.At the time,the pressure inside the centrifugal pump volute and at volute outlet decreases obviously.The pressure pulsation amplitude of each monitoring point has obvious periodicity.Volute tongue,the pressure pulsation amplitudes at monitoring points of the first section and the volute outlet present a trend of decrease first and then increase with the increase of cutting width,when the blade outlet relative cutting width is 33.33%,the pressure fluctuation amplitude in the centrifugal pump reaches the minimum.