A mixed-flow pumping system was selected as the study case based on CFD technologies. Two difference methodologies of flow field analysis and performance prediction were conducted. One method was that the system efficiency was the production of pump efficiency with passage efficiency obtained by separate numerical simulation of suction box and discharge passage without pump. The other one was based on the simulation of whole pumping system including the suction box, discharge passage and pump. The predicted results from the two different methodologies were compared with model system test results, which showed that the predicted errors were different. The error of pumping system efficiency was smaller when the numerical simulation of whole pumping system was adopted, while the error was much greater when the system efficiency was predicted by the production of passage efficiency with pump efficiency, approximately equal only near the best efficiency point. The larger errors in predicting pumping system efficiency for the first method were mainly caused by unreasonable theoretic foundation. Therefore, it is suggested that the suction box, discharge passage and pump should be taken as a whole in numerical simulation and performance prediction and the effect of pump should be considered in the optimal hydraulic design of suction box and discharge passage.%以某混流泵装置为例,采用CFD技术分别进行包括进出水流道和水泵在内的水泵装置全流道数值模拟的性能预测和由不带泵进出水流道数值模拟得到的流道效率与泵效率乘积的泵装置性能预测,并与模型装置试验结果进行比较.结果表明,根据水泵装置全流道数值模拟方法进行的装置性能与模型试验结果误差较小;以流道效率与泵效率乘积的方法预测装置效率的误差较大,仅在最优工况点附近与模型试验泵装置效率近似相等,引起较大误差的主要原因是基本理论存在不合理性.因此,建议以进水流道、出水流道和水泵作为整体进行内流数值模拟和装置性能预测,并在考虑泵对流道影响的情况下进行流道的水力设计优化.
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