叶轮直径对双蜗壳离心泵压力脉动特性的影响

The Influence of Impeller Diameter on Pulsation Characteristics of Double Volute Centrifugal Pumps

为分析叶轮直径对双蜗壳离心泵压力脉动特性的影响,采用SST k-ω湍流模型和SIMPLEC算法对不同叶轮直径下的双蜗壳离心泵进行数值计算,将外特性参数试验结果与计算结果进行对比。研究表明,离心泵外特性参数(扬程H与输出功率P)随直径变化是等梯度的,并且计算值与试验值基本吻合;小流量工况下压力脉动幅值高于其他流量工况,叶轮直径变化会使叶片弯曲度发生改变,受动静干涉以及射流-尾迹的影响会出现脉动叠加现象,从而在叶片通过频率的倍频处(3fBPF或4fBPF)产生高幅值脉动;隔舌区域流动混合现象最为明显,且除D^2/D2=1(模型3)以外,隔舌位置处的压力脉动峰值均出现在叶片通过频率处。对于所选取的模型,除过隔舌区域监测点之外的其他监测点处压力脉动峰值处的脉动幅值随叶轮直径增大逐渐增大,且最大幅值波动达到23.8%。叶轮直径变化时射流-尾迹与动静干涉作用对离心泵内部压力脉动特性有重要影响。

In order to analyze the influence of impeller diameter on the pressure pulsation characteristics of the double volute centrifugal pump,the SST k-ωturbulence model and SIMPLEC algorithm are used to calculate the double volute centrifugal pump under different impeller diameters.Compared the experiment results of the external characteristic parameters with the calculated results.The research shows that the external characteristic parameters of the centrifugal pump are equi-gradient with the change of the diameter,and the calculated values are basically consistent with the experiment values.Under the low flow rates,the pressure pulsation amplitude is higher than other flow rates.The impeller diameter change will change the blade curvature,and the pulsation superposition phenomenon will occur due to the rotor-stator interaction and the jet-wake,thereby generating a high amplitude pulsation at a frequency doubling of the blade passing frequency(3fBPFor 4fBPF).The flow mixing phenomenon is most pronounced in the tongue region,and except for D^+2/D2=1(model 3),the pressure pulsation peak at the tongue position appears at the blade passing frequency.In the model selected in this paper,the pulsation amplitude at the peak of the pressure pulsation at other monitoring points except the monitoring area of the tongue area gradually increases with the increase in the diameter of the impeller,and the highest amplitude fluctuation reaches 23.8%.The jet-wake and rotor-stator interaction under the impeller diameter change have an important influence on the internal pressure pulsation characteristics of the centrifugal pump.