Numerical study on pressure fluctuation of a multistage centrifugal pump based on whole flow field

Abstract

Multistage centrifugal pumps can provide high-pressure fluid flow, and is widely used in various engineering applications. However, the pressure fluctuation in the pumps strongly affects the flow and pressure stability. To gain further insight into the pressure fluctuation of multistage centrifugal pumps, a numerical model of a typical multistage centrifugal pump model was constructed and the flow investigated systematically under different operating conditions. Changes in amplitude, frequency, and phase of pressure fluctuation in the impellers, diffusers, and pump cavities were observed and analyzed in both time-domain and frequency-domain. The pressure fluctuations of the fluid in the impeller were found to originate from the inlet side of the outward diffuser, whereas that in the diffuser arose from the outlet side of the impeller blade. In contrast, the pressure fluctuations in the pump cavity were initiated from the outlet side of the impeller blade and the interstage leakage of fluid. This study also conclude that the pressure fluctuations are essentially a wave with identifiable amplitude, frequency, and phase.