Analysis Of The Affect Caused By The Slip Factor To The Characteristics Of The Centrifugal Pumps

Slip factor is the key to the calculation of the theoretic head when we design pumps. But because of the affect of many factors, the development of the centrifugal pump design theory is restricted by the precision of the slip factor. This paper modifies the flow slip value at the end of the impeller by analysis the cause of the factors which affect the slip factor. And by comparison of the experimentation data with the value got by the numerical simulation, the affect caused by the slip factor to the characteristics of the centrifugal pumps had been analyzed.Firstly, by the analysis of the axial eddy, secondary flow and change of the impeller blade shape, we know that these factors will enlarge the flow slip value and reduce the slip factor. According to the definition of the slip factor, the calculation of the flow slip value is right or not affects the precision of the slip factor. So, this paper modifies the flow slip value.Secondly, this paper analyzes the connection between the slip factor and characteristics of the centrifugal pumps. The formula that calculates the theoretic head must be different because of the different definition of the slip factor to insure the precision.Thirdly, the three-dimensional models of the impeller and volute channel are built by the PRO/E. The grid of the flow field is created and the boundary conditions and body types are presented in Gambit. The model is simulated in FLUENT and the data of the flow field can be got. By dealing with the flow field data, we get existent evidence of the factors which affect the slip factor and pickup the data which is needed when calculate the characteristics of the centrifugal pumps.Finally, by contrast the experimental data with the simulation data and the value after modifying, the efficiency of the modify process can be validated. The function between the modify modulus and the specific speed can be found by regression analysis. And the result of the modification can be validated.