径向回流平衡孔低比转数离心泵空化性能研究

Cavitation Performance of the Low Specific-speed Centrifugal Pump with Radial Reflux Balance Hole

选用ns=26的低比转数离心泵为计算模型,保证蜗壳和叶轮其他几何参数不变的前提下,平衡孔中的液体分别采用径向回流、传统轴向回流以及无平衡孔结构这3种方案,基于混合流体的连续性方程、动量方程、标准k-ε湍流模型、均质多相模型和Rayleigh-Plesset方程对叶轮内的空化进行数值模拟。计算得到的H-LNPSHa曲线与试验结果吻合较好,验证了计算方法的准确性。研究结果表明:具有径向回流平衡孔的低比转数离心泵平衡孔回流方向与叶轮来流方向基本一致,能够明显改善该泵的空化性能。

The low specific-speed centrifugal pump with the specific speed of 26 was selected to be the numerical model.Under the condition of other geometric parameters of the volute and impeller maintained constant,the radial reflux balance hole,the traditional axial balance hole and none balance hole were designed to couple with the low-specific centrifugal impeller respectively.Based on the continuity equation,momentum equation,standard k-ε turbulence model,homogeneous multiphase model and Rayleigh-Plesset equation,the cavitation performances of the pump with different reflux balance holes were simulated.The trend of simulated H-LNPSHa curves were consistent with the experimental data,in addition,the accuracy of numerical simulation was also verified.The results showed that with equipped radial reflux balance hole,the anti-cavitation performance of the pump can be improved obviously due to the coincidence between the balance-hole backflow with impeller inflow.