Numerical Analysis of Stress and Deformation of Impeller in the Mixed Flow Pump Based on Fluid-structure Interaction

Abstract

To improve the operational reliability of mixed flow pumps, the two-way coupling fluidstructure interaction method is applied to investigate stresses and deformations of the impeller. The Reynolds-averaged Navier–Stokes equation, coupled with the SST k-ω turbulent model, is solved in the fluid domain by using ANSYS CFX, while transient structure dynamics in the structural domain are calculated with the finite element method. The accuracy of the numerical results has been verified by experimental pump performance. The results show that the flow rate definitely has a noticeable effect on both deformations and stresses. With the flow rate increasing, the impeller deformation decreases, as well as the stress, which is completely different from centrifugal pumps, but similar to axial pumps. Moreover, a local maximum deformation occurs in the middle of blade inlet, and the maximum stress of the entire impeller fluctuates periodically. On the same shroud, the stress on the suction side is higher than the pressure side along the intersection path; and on the same side, the mean stress on the rear shroud is larger than the front shroud. This study can help understand the distribution of both deformations and stresses in the impeller and provide guidance for improving the operation safety of mixed flow pumps.