Correlation study between internal flow and vibration characteristics in centrifugal pumps at different cavitation levels

The vibration signal is commonly used to detect the cavitation phenomenon in centrifugal pumps in order to investigate the vibration characteristics of centrifugal pumps with different cavitation degrees and then provide the basis for predicting the critical cavitation point of the pump in advance. This paper takes ns = 35 centrifugal pump as the research object and establishes the quantitative relationship between vorticity and entropy generation and vibration energy by studying the internal flow and vibration response of the centrifugal pump under different cavitation degrees. The study shows that with the development of cavitation, the bubble volume inside the impeller channel gradually increases, and vortices with a larger area appear inside the channel and gradually move toward the impeller outlet. The vorticity and entropy generation of the secondary information of the internal flow field during cavitation have a good third-order fit to the vibration energy, and with the increase in the vorticity and entropy generation, there exists a relationship of a third-order polynomial that first increases and then slows down and finally increases rapidly.