VALIDATING FULL CAVITATION MODEL WITH AN EXPERIMENTAL CENTRIFUGAL PUMP

Abstract

The full cavitation model is increasingly applied in the cavitating flow simulation and the cavitation performance prediction of a centrifugal pump to improve or optimize its hydraulic design. Since the model involves surface tension and non-condensable gas content, it can be potentially applied in predicting cavitation behaviour of a centrifugal pump when handling viscous oils that possess different surface tension and gas content than water. However, the model has not been validated extensively against experimental incipient cavitation and NPSHr (net positive suction head required) data so far. In the paper, the cavitation performance of an experimental centrifugal pump is investigated using the CFD code and the full cavitation model when pumping water. The incipient cavitation number-flow rate curve and head-NPSHa (net positive suction head available) relationship are established and compared with experimental observations. The relationship between the head and integrated vapour-liquid volume ratio in the impeller is argued. The influence of the non-condensable gas content and turbulence model on the head-NPSHa curve is clarified. The cavity pattern predicted is compared with the visualized one. The computational methods adopted and the results achieved here can be useful for the cavitation performance prediction of a centrifugal pump in engineering.

Keywords

• centrifugal pump
• cavitation
• incipient cavitation
• suction performance
• net positive suction head required
• net positive suction head available