大型水泵装置全流道数值模拟与性能预测

采用计算流体动力学方法，对某大型混流泵装置进行了全流道数值模拟，对有泵与无泵进、出水流道的内部流动及水力损失进行了对比分析，实现了水泵装置性能预测．研究发现，水泵叶轮旋转和导叶出口剩余环量与进、出水流道的内部流场相互作用，进水流道的出口水流条件和出水流道的进口水流条件与单独计算时的假定有本质不同，对进、出水流道的水力损失和装置性能有显著的影响．在水泵装置中，进水流道的水力损失小于无水泵时的流道水力损失，在一定流量范围内，仍基本符合二次抛物线规律．与此相反，出水流道的水力损失远大于无水泵时的水力损失，在设计流量附近出现局部极小值，不再完全符合二次抛物线规律．数值计算结果得到了模型试验的验证．

Numerical simulation and performance prediction for large pumping systems

The method of computational fluid dynamics is adopted to simulate the internal flow of a large mixed-flow pumping system. Comparison and analysis are made on the internal flow and hydraulic losses of suction box and discharge passage with and without pump, and the performance of the pumping system is predicted. The computational results show that the rotation of impeller and the residual circulation in the outlet of diffuser interact mutually with the internal flow fields of suction box and discharge passage. The flow conditions in the outlet section of the suction box and in the entrance section of discharge passage are substantially different from those assumed in numerical computation, resulting in notable influence on hydraulic losses and pumping system performance. The hydraulic loss of suction box in the pumping system is less than the numerically computed value. On the contrary, the hydraulic losses of discharge passage in the pumping system are much greater than that without pump, and a minimum extreme value exists in the vicinity of designed flow rate, not obeying the rule of second parabolic curves any more. The validity of simulation results is verified by model tests.