A Numerical Simulation of Head and Radial Hydraulic Forces on Screw Centrifugal Pumps with Different Clearances

Based on Navier-Stokes equations and standard κ-e turbulence model,the flow in a screw centrifugal pump is simulated to predict the performance of the pump,using SIMPLEC algorithm with different clearances between the impeller and the suction chamber.The head and radial hydraulic force on the impeller and volute with four clearances are analyzed and compared.The results indicate that the head will descend with the increase in the clearance,especially when the clearance is over 1mm.The radial hydraulic force has similar variation trend as the flow rate changes,while the radial force on the volute will decrease more than that on the impeller with the same flow rate variation.The clearances do not have a great influence on the radial hydraulic force in the impeller and volute.With four clearances the radial hydraulic forces all reach the minimum when the flow rate is 0.75 times of the design discharge,the values of which are significantly over that presented by Stepanoff.The experimental coefficient of the radial force theoretical prediction is around 0.25 in the screw centrifugal pump.