Effects of guide cone configuration on hydraulic performance of low-head pumping station
Zhou Peijian1, Wang Fujun1, Zhang Zhimin2
1.College of Water Resources & Civil Engineering, China Agricultural University, Beijing 100083, China; 2.Tianjin Institute of Hydroelectric and Power Research, China Institute of Water Resources and Hydropower Research, Tianjin 301900, China
Abstract：In order to investigate effects of guide cone on hydraulic performance of low-head pumping station, five different guide cone configurations, namely straight, hyperbolic, quadratic, arc and elliptical cones are designed for Xinkaihe Pumping Station. The 3D flow field in the flow passages accommodating an axial-flow pump in that station is simulated by employing CFD method. It is turned out that the guide cone has a large effect on flow pattern in the pump sump. All the guide cones can prevent the occurrence of the floor-attached vortices in the pump sump. For the straight, hyperbolic, pa-rabolic and arc cones, one sidewall-attached vortex and two free surface vortices emerge. For elliptical cone, however, only one sidewall-attached vortex and a free surface vortex are identified. Comparing with the case without guide cone, the elliptical cone has reduced the number of vortices. Additionally, guide cones also have a remarked effect on hydraulic loss in the pump sump. The hydraulic loss is the minimum for the sump with elliptical cone, but the loss for the rest cones is larger than the one without guide cone. Comparing the flow at the outlet of sump across the configurations by means of the axial velocity uniformity and velocity-weighted average swirl angle, it was shown the elliptical cone has the best rectification effect on flow. Finally, the hydraulic efficiency was analyzed for the flow passages with various guide cones, and it was demonstrated that the elliptical cone can result in an improved hydraulic efficiency compared with the others.
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