Effects of impeller geometry parameters on fracture cavitation performance of centrifugal pump
KANG Junjun1*, ZHU Rongsheng1, WANG Xiuli1, LIU Yong1, ZHONG Weiyuan1, ZHANG Benying1, QI Longxi2
1.National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 2.Jiangsu Jiangjin Pump Industry Co. Ltd., Taizhou, Jiangsu 225300, China
Abstract：To improve the cavitation performance and study the cavitation fracture mechanism of the centrifugal pump, the numerical simulation of cavitation performance in a specific speed 134 centrifugal pump was carried out by changing the impeller inlet diameter, the blade inlet angle and the impeller outlet width. Then the cavitation performance was predicted according to the simulation results, and the bubble distribution in the impeller passage was analyzed under different net positive suction heads. Simulation results showed that with the decreasing of the inlet pressure, the cavitation bubble first occurs at the blade inlet of the suction side, then it diffuses to the impeller outlet with the rotating of the impeller at the same time, and the bubbles flow to the pressure side when the flow area becomes bigger. The main reason why the bubble in the impeller passage is asymmetric is that the pressure on the surface of the impeller is asymmetric because of the static coupling between impeller and volute. Compared to the impeller inlet parameters, the change of the impeller outlet width affects the cavitation performance less. The bending of the blade becomes smaller when the inlet angles become bigger, the flow areas in the blade inlet increase, the cavitation performance is improved and the value of the NPSH decreases under the same inlet pressure. There exists an optimum value for the change of the impeller inlet diameter and the blade inlet angle, which is of importance to the improvement of the centrifugal pump′s efficiency and the cavitation performance.
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