Detection of Cavitation through Acoustic Generation in Centrifugal Pump Impeller

Abstract

The most common device which transport fluid in industries, agriculture as well as domestic water supply is the centrifugal pump. Based on fluid transfer conditions, several let-downs are occur in the centrifugal pump, cavitation is one among them. The flow pattern at the eye of impeller deviates from the ideal case with the occurrence of cavitation. Due to cavitation, vibration occurs on blades that generates noise in pump. In this study, the acoustics generated in centrifugal pump impeller due to cavitation is detected with the sound pressure by using 3-Dimensional, steady and unsteady state computational fluid dynamics (CFD) analysis of an industrial centrifugal pump impeller. Harmonic force analysis with blade row model helps in finding the sound pressure. The acoustics generated with unsteady-state is compared with cavitation at steady-state CFD analysis. The Reynolds averaged Navier-Stokes equations model as well as Shear Stress Transport (SST) turbulence model are used for the CFD simulation. The results show that the sound pressure calculated increases with the increase in cavitation (i.e. formation of vapour bubbles and sudden drop in head) which shows that high noises are generated by centrifugal pump impeller at lower net positive suction head (NPSH) at a particular discharge.

Keywords

• Centrifugal pump impeller; Cavitation; Net positive suction head (NPSH); Acoustics; Sound pressure; Vapour volume fraction.