Prediction of cavitation performance of radial flow pumps

Cavitation is a major problem in pump design and operation because this phenomenon may lead to various types of instabilities, including hydraulic performance loss and catastrophic damage to the pump material caused by bubble collapse. Therefore, it is critical to predict the cavitation performance of the pump in the design phase itself. The motivation of this study is to develop a systematic methodology to calculate the cavitation performance of radial flow pumps. In the first step of the present work, a cavitating nozzle flow case for which the bubble dynamic behavior is accurately resolved in literature is studied numerically. Subsequently, the capabilities of three cavitation models, implemented in the commercial code Fluent, are evaluated for three radial flow pumps designed at specific speeds n_s = 10.4, 22.4, and 34.4. The numerical results are validated with global quantities based on net positive suction head (NPSH) measurements. The results led to the determination of reasonably accurate NPSH values for the defined range of specific speeds.