Cavitation Characteristics and Internal Flow of a Closed-Type Single Blade Centrifugal Pump

Abstract

In this study, cavitation tests and cavitation CFD analysis were conducted to elucidate the mechanism of head reduction when cavitation occurs in a closed-type single blade centrifugal pump. In addition, the hydraulic loss during the cavitation process was evaluated, and the relationship with the vortex structure in the impeller in the point of no pressure change and at the head drop point was investigated. As a result, the vortex generated in the impeller was larger at the head drop point than in the point of no pressure change, and impeller loss, in particular, increased. Vortices are generated in the impeller at the head drop point due to cavitation on the shroud side of suction surface near the blade inlet. Cavitation and the vortices generated due to cavitation were found to be the cause of increased impeller loss. As a result, it is possible to effectively improve the cavitation performance of the pump by suppressing the vortices that cause head reduction and the cavitation that induce these vortices.