Study of Hydrofoil Unstable Partial Cavitation Emphasizing Unstable Sheet Cavitation Phenomenon

Abstract

Unstable partial cavitation phenomenon often occurs during the operation of axial flow pumps. In this paper, the hydrofoil of an axial flow pump is taken as the research object, and the cavitation morphology at the design angle of attack is obtained by high-speed photography. And the flow characteristics under the transformation cavitation number of sheet cloud cavitation are studied by SBES turbulence model. The hydrofoil has hydrodynamic phenomena such as unstable sheet cavitation and multistage cloud cavitation. The high pressure propagating upstream from the trailing edge may be the cause of secondary cloud shedding, and the closer to the hydrofoil wall surface, the greater the intensity of this pressure. The frequency of unstable sheet cavitation shedding is 166.6 Hz. The instable closure of cavitation and the hydrofoil wall may be the main cause of unstable sheet cavitation formation. The generated quasi-periodic re-entrant jet will have a greater impact on the flow in the rear of the hydrofoil. This study provides reference for the design and operation of axial flow pumps and prevention of cavitation damage.