Study on the effect of an inducer on the cavitation characteristics of low-specific-speed onboard cooling pumps

Abstract

Abstract In this study, numerical simulations using the SST k-ω turbulence model and the Zwart-Gerber-Belamri cavitation model are coupled with experimental validation to systematically analyze the effect of an inducer on the internal flow field and cavitation performance of a pump under various operating conditions. The optimal matching angle between the inducer and the impeller is also investigated. The results indicate that following the pressurization and preswirl induced by the inducer, the areas of the low-pressure and low-velocity zones at the impeller inlet are significantly reduced, while the size and intensity of the vortices near the outlet region within the impeller also decrease. Under rated and high-flow-rate operating conditions, the inducer enhances the cavitation resistance of the centrifugal pump and mitigates the formation and growth of cavitation bubbles inside the impeller. However, with increasing impeller speed, when the speed reached 12,500 r/min, severe cavitation occurred within the inducer, thereby diminishing its cavitation suppression effect and intensifying the cavitation phenomenon within the impeller. The matching angle between the inducer and the impeller not only affects pump performance but also significantly influences its cavitation resistance. This angle θ is formed by fixing the impeller and rotating the inducer circumferentially, which denotes the circumferential offset angle of the inducer blade outlet edges before and after rotation. When the angle θ  = 120°, the inducer exhibits the most pronounced cavitation suppression effect within the impeller. These findings offer valuable engineering guidance for the study of cavitation resistance in low-specific-speed onboard cooling pumps operating at high speeds.