Study on external performance and internal flow characteristics in a centrifugal pump under different degrees of cavitation

Cavitation as a form of unsteady flow within centrifugal pumps can cause the reduced performance of pumps, disordered internal flow regimes, and flow loss. The present criterion used for determining the occurrence of cavitation is a 3% head drop. However, in most cases, pump cavitation already occurs with less than a 1%-2% head drop due to significant changes in the internal flow status. To examine changing patterns in internal flow characteristics as the degree of cavitation deepens in the early stage of cavitation in centrifugal pumps when the head curve does not show significant fluctuation, this paper focuses on a low specific speed centrifugal pump to analyze distributions of total internal pressure, speed, bubble volume, vortex structure, and entropy generation across different degrees of cavitation and obtain internal flow characteristics and flow loss patterns of pumps, with an aim of providing preferences for anti-cavitation hydraulic design of centrifugal pumps.

Automated summary

Cavitation in centrifugal pumps can lead to reduced performance, chaotic flow regimes, and flow loss. The current criterion for determining cavitation occurrence is a 3% head drop, but cavitation often occurs with less than a 1%-2% head drop due to significant changes in internal flow. This paper focuses on analyzing the changing patterns in internal flow characteristics during the early stage of cavitation in a low specific speed centrifugal pump. By examining distributions of total internal pressure, speed, bubble volume, vortex structure, and entropy generation, the study aims to provide insights for anti-cavitation hydraulic design of centrifugal pumps.