Experimental investigation into effects of sump shape on suction vortex
XIAO Ruofu1,2, LI Ningning1,2
1.College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, China; 2.Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System, Beijing 100083, China
Abstract:Serious vortices in pump sumps can lead to cavitation in a pump, subsequently the pump characteristics are affected in operation. In order to improve the flow regime in a sump and prevent vortices from entering into the bell-mouth, a series of high-speed photography and PIV experiments are carried out at different submerged depths and flow rates in an open sump firstly, then, according to visualized flow patterns, two measures, namely a rectangular sump with and without bottom cross, are put forward to improve the flow pattern; finally, their effects on vortex elimination are observed. The results show that the rectangular sump without bottom cross is able to improve the flow regime in the sump and to reduce the minimum submerged depth, the surface spiral vortex intensity can be reduced under the same operating condition. For the rectangular sump with bottom cross, the effect of vortex is suppressed further, and the minimum submerged depth is reduced once more and the surface spiral vortex intensity is dampened. This study makes significant sense in lowering allowable submerged depth and reducing engineering costs of pump sump.
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