Flow characteristics of low-lift and large flow rate pump installation in saddle zone
Zheng Yuan1, Mao Yuanting1, Zhou Daqing1, Zhang Dan2
(1.School of Energy and Electrical Engineering, Hohai University, Nanjing, Jiangsu 210098, China; 2.Ertan Hydropower Development Company Ltd., Chengdu, Sichuan 610021,China)
Abstract：Numerical and experimental methods were applied to investigate the axial pump flow characteristics in the saddle zone. The standard k-εturbulence model and SIMPLEC algorithm were chosen in computation fluid dynamics software Fluent, the Reynolds averaged Navier-Stokes equation was dispersed by the finite volume method, and external characteristics of axial pump model were numerical simulated in a test facility from 20% to 130% of designed flow rate. The results between numerical calculation and model experiment were compared. Flow characteristics in saddle zone were studied by comparing flow patterns between designed condition and small flow rate condition. The results show that unsteady operation saddle zone exists between 50% of designed flow rate and 65% of designed flow rate. Large range recirculation and vortex exist at the inlet and outlet of the impeller under small flow rate condition. Intensive power exchange is the main cause of the pump unstable operation.The results of three dimensions CFD simulation and test results agree well near the best efficiency point, and deviations are up to 5% at part load condition, which indicates the effectiveness and accuracy of numerical simulation.
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