Dynamics analysis on cavitation flow field of centrifugal pumps using modal order reduction

Abstract

Throughout the operational lifecycle of centrifugal pumps, cavitation is an omnipresent phenomenon that frequently leads to cavitation erosion and a decline in hydraulic heads, leading to mechanical failures and substantial damage to the pump assembly. Although the cavitation phenomenon has been widely studied in existing literature, it is still a challenging task for reliable flow dynamics analysis of centrifugal pumps using the modal order reduction technique. In this study, the modal decomposition and reconstruction of the flow field of a centrifugal pump considering the cavitation are conducted. The dynamic modal decomposition (DMD) based on the singular value decomposition (SVD) is employed to explore the dynamic behaviour of the cavitation flow field by reducing the modal order of the flow field. Then, the modal characteristics of the pump flow field are systematically analyzed. The results demonstrate that the DMD method can improve the accuracy of the order reduction model and reduce the modal reconstruction error, the reconstruction error loss is less than 5%, and the calculation efficiency is significantly enhanced to analyze the pump cavitation flow field. In addition, a comparison of the calculation data between the finite element simulation and the DMD reconstructed flow field indicates the potential application of the DMD method in investigating the degradation of the flow field due to cavitation, which provides new perspective and solid technique support for centrifugal pump cavitation analysis.