Study On Hydraulic Optimization And Performance Of Large-size Vertical Centrifugal Pump

The distribution of water resources in China is very uneven,which does not match with the population,land and economic structure of our country.In order to solve this problem,our country has implemented a series of large-scale water diversion projects,which has greatly improved the urban and industrial water use in the corresponding areas,and promoted the rapid development of regional economy.In this paper,Niulanjiang-Dianchi water project dry river pumping station of high power and high lift centrifugal pump research project,with the largest shaft power in China than the low speed vertical single-stage single suction centrifugal pump as the research object.The paper discusses the development process of the large centrifugal pump in the dry river pumping station and the corresponding results obtained.Firstly,according to the basic design parameters and operating conditions of the pump station,the speed of the pump and the installation height are determined.Reference to the selection of specific speed of pump impeller model based scheme,hydraulic development with CFD technology using local and global optimization method combining with the test results of pump model,optimize the index of cavitation performance of the pump,and system analysis to optimize the pump model under three operating conditions of pump internal flow characteristics and the corresponding performance index.Secondly,the comprehensive performance of the model pump is analyzed by the system of high head hydraulic test bench.Experimental research includes aspects such as efficiency characteristic test,cavitation characteristic test,pressure pulsation test and the four quadrant test.The experimental results show that the efficiency of the pump in the operating range of high efficiency characteristic curve is wider,the head curve to avoid the hump area,the pump cavitation and pressure pulsation index meet the design requirements.Finally,the characteristics of the centrifugal pump under the condition of zero flow rate and small flow rate are study.Combining the CFD analysis and the field test,the characteristics of the head under the condition of small flow rate and zero flow rate were analyzed.The results show that the head of zero flow conditions is higher than the maximum design head,and there is a certain margin,zero flow head prototype pump field test is far greater than the results of model test;numerical simulation of CFD pump head characteristic analysis,model test and the actual conversion difference,zero flow and small flow pump CFD mathematical analysis model,model and prototype conversion methods need to be further improved.The results show that the head of the zero flow operating point is higher than the maximum design head,and there is a certain margin,the zero flow head of the prototype pump field test is much larger than the model test results;CFD numerical simulation of pump head characteristic analysis,model test and the actual conversion difference,zero flow and small flow pump CFD analysis mathematical model,the model and the prototype conversion methods need to be further improved.