Investigation on the added mass effect of centrifugal impellers with splitter blades

Abstract

During the operation of the centrifugal pump, the impeller is easily resonated by multi-frequency fluid excitation, so it is necessary to perform modal analysis on the impeller to ensure the safe operation of the unit. In this paper, taking a certain type of centrifugal pump impeller as the research object, the dry and wet modal characteristics of the impeller are studied by acoustic fluid-structure interaction method, and the effects of the number of splitter blades and circumferential position of the splitter blades in the duplicated sector on the natural frequency are analyzed. The results show that the natural frequency of the impeller decreases significantly compared with the natural frequency in air due to the added mass effect of the fluid. Adding splitter blades between the main blades of the impeller will reduce the natural frequency of the impeller in air and water, and the frequency drop rate and added mass coefficient will decrease; the position of the splitter blades in the circumferential direction of the impeller has little effect on the natural frequency of the impeller.