Optimal Design And Test Research Of Low-specific-speed Centrifugal Pump Based On CFD Technology

Low-specific-speed centrifugal pumps with a small flow, high head characteristics, arewidely used in the fields of petroleum, chemical. The centrifugal impeller is a critical flowcomponent for energy conversion, so optimizing design of impeller has important significance ofsaving energy and reducing consumption. In this paper, combined with the characteristics oflow-specific-speed centrifugal pump, the centrifugal impeller with main blade and splitter bladeis optimized based on the efficiency as optimization object. In the process of optimization, theimpeller blade outlet bias extent, circumferential position and initial diameter of splitter blade areselected as the control parameters. The ranges of these three parameters are set according to theprototype pump. Finally, the optimal model is obtained combined with genetic algorithm andartificial neural network. And the flow field in centrifugal pump with the impellers before andafter optimization is numerically simulated, the flow and performance of the pump arecomparatively analyzed. The numerical result of performance is verified by the externalcharacteristics of the experiment.(1) The solid model of flow components in pump was built using UG3d modelingsoftware, including the inducer, centrifugal impeller with main blade and splitter blade,volute. Their flow passage is meshed using hexahedral structured grid by NUMECAsoftware.(2) The geometry of impeller was parametric modeling. And two optimization programshad been proposed based on the efficiency as object. One program is that only initialdiameter of splitter blade is considered as optimization variable, the other is that thecircumferential position θ of splitter blade and impeller blade outlet bias extent H4areconsidered as optimization variable. So centrifugal impeller is optimized and two optimalmodels with high efficiency are obtained adopting two programs..(3) Based on Navier-Stokes equation and Spalart-Allmaras turbulence model, the wholeflow field of centrifugal pump with three impellers before and after optimization werenumerically simulated. The reason of performance improvement for optimized pump is analyzedby comparing the change of the flow field inside the pump. (4) The external performance experiments for centrifugal pumps with impeller before andafter optimization are also carried out. The accuracy of numerical simulation and reliability ofoptimization is verified by the external characteristic curve.