Head degradation mechanism research on mixed-flow pump under cavitation conditions
Shi Wei1,2, Zhang Daqing1, Pan Zhongyong1, Li Yanjun1, Yuan Shouqi1
1. Research Center of Fluid Machinery Engineering and Technology, Jiangsu University, Zhenjiang, Jiangsu 212013, China; 2.Jiangsu Water Supply Co.Ltd., for East Route of South-to-North Water Diversion, Nanjing, Jiangsu 210029, China
Abstract：The cavitating flow in a mixed-flow pump with volute collector(the specific speed ns=449)under design condition was simulated numerically based on the cavitation model Rayleigh-Plesset equations and the SST turbulence model. The NPSHA-H curve was obtained accordingly.To investigate the inherence of mixed-flow pump cavitation breakdown condition and head degradation, the cavitation phenomenon in the impeller were comparatively analyzed under the inception,critical and severe cavitation conditions.The numerical simulation results and experimental ones were consistent with the error less than 5%. When the cavitation bubble in the flow passage adds up to a certain extent, it will make the liquid boundary layer separation and produce vortexes, which can be observed from the picture of vapor volume fraction distribution in impeller passage and streamline distribution on blade suction side. Vortex is the main cause of the mixed-flow pump cavitation breakdown and head degradation. The regularities of distribution of mixed-flow pump cavitating flow field were revealed.
施伟,, 张大庆, 潘中永, 李彦军, 袁寿其. 蜗壳式混流泵空化工况扬程下降机理[J]. 排灌机械工程学报, 2013, 31(10): 851-855.
Shi Wei,, Zhang Daqing, Pan Zhongyong, Li Yanjun, Yuan Shouqi. Head degradation mechanism research on mixed-flow pump under cavitation conditions. Journal of Drainage and Irrigation Machinery Engin, 2013, 31(10): 851-855.
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