Noise characteristics in a centrifugal pump with a fan type inducer of blades composed by multiple airfoils under cavitating conditions

Cavitation is not only a cause of decreased suction performance of centrifugal pumps, but also a source of noise, so it requires suitable handling. In a previous study, noise, and cavitation in a centrifugal pump with low solidity inducer were experimentally analyzed to clarify the relationship. However, it is not clear whether a specific trend exists between pump operation and noise, even for more complex internal flows, since the blades of this inducer have a simple, nearly flat shape. In this study, a centrifugal pump with a low solidity fan type inducer with blades composed of multiple airfoils was used as a test model. Experiments were conducted using the pump to measure pump performance and noise under various pump operating conditions, including cavitating conditions. In addition, paint erosion tests were conducted under each operating condition to investigate the area where cavitation bubbles collapse on the inducer blade, which is one of the causes of the noise. The analysis of these results showed that specific trends exist between pump operation and noise, even when an inducer with complex geometry is attached.