多级离心泵内部间隙流动与泄漏损失

Internal clearance flow and leakage loss in multi-stage centrifugal pump

为研究多级离心泵前后密封口环对整体水力性能和容积损失的影响,以某高压离心泵为分析模型,建立叶轮、导叶和密封环一体化的整体模型并进行了三维流场模拟,得到不同工况下多级泵的水力性能和口环间隙泄漏量,分析间隙内的流场结构.结果表明,考虑环形间隙结构的全模型性能预测结果与试验值取得较好的一致,在设计点附近的泄漏量预测值与经验公式计算结果接近.高压多级离心泵内部泄漏损失对性能存在明显的影响,间隙内的回流和叶片出口处的损失随流量增加而减小,相反地,叶轮入口处的损失因流量和间隙泄漏量增加而增大.

To investigate the influence of the annular seal on the hydrodynamic performance and the clearance leakage characteristics in multi-stage centrifugal pump,a high-pressure centrifugal pump model containing impeller,guide vane and annular seal was established to simulate the three-dimensional flow field.The hydrodynamic performance and leakage flux of the multi-stage pump under different operating conditions were obtained.The flow structure in the impeller clearance was analyzed.The numerical results of the whole model with impeller clearance are similar to the experimental results,and the calculation leakage flux is closer to empirical formula at best efficiency point of pump.The leakage loss of high pressure multi-stage centrifugal pump can＇t be ignored.The inverse flow in the impeller clearance was alleviated and the loss in the impeller outlet decreases with flow rate increasing.On the contrary,the loss in the impeller inlet increases because of the large flow rate and serious leakage.