The Influence of Vaned Diffuser Outlet Diameters on Operating Performance of a Single-Stage Centrifugal Pump

To enhance the efficiency and stable operation, the unsteady pressure fluctuations in a centrifugal pump and the radial force on an impeller are investigated for three different vaned diffuser outlet diameters. The steady-state hydrodynamic performance of the centrifugal pump with three different vaned diffuser outlet diameters was experimentally measured. Numerical simulations were used to obtain the hydrodynamic performance of the experimental centrifugal pump based on the Reynolds-averaged Navier-Stokes (RANS) and turbulence models. The numerical results of the hydrodynamic performance were in agreement with the experimental data. The accuracy of the utilized numerical approach was demonstrated. The unsteady flow characteristics of the centrifugal pump were numerically studied. With increasing diffuser vane outlet diameter, the flow field within the volute became more non-uniform, and the pressure fluctuation was more drastic. Moreover, because of the influence of the non-uniform flow field and the pressure fluctuation, the radial force on the impeller increased.