Visualization of Vortices in Pump Sump

Abstract

Large pump and axial pump are sensitive to adverse vortices in pump sump. The sump should be designed to prevent free-surface and submerged vortices within the fixed limits, and allow the pump to achieve its optimum hydraulic performances. This paper illustrates the visualization methods and examples of vortices in pump sump by experiment and CFD. In TSJ standard for model test vortex types are identified by the naked eye, while in HI standard vortices are visualized with the help of dye and artificial debris. Both in these standards, free-surface and submerged vortices entering the pump must be less severe than the acceptance criteria. Recently CFD for vortex prediction in pump sump has developed rapidly. RANS and LES methods can be classified according to the difference of viscosity model. RANS method has important achievements due to the actual calculation cost.