Detailed flow characteristic analysis of a three-stage centrifugal pump at design and off-design conditions

This paper presents a detailed analysis of the internal flow characteristics of a three-stage centrifugal pump at design and off-design conditions. Numerical analysis is conducted by solving three-dimensional steady and unsteady Reynolds-averaged Navier – Stokes equations with the shear stress transport (SST) turbulence model. The results of steady and unsteady numerical analyses are analyzed and compared with experimental data throughout the flow region. Moreover, a reattachment modification in the SST turbulence model is applied to better capture the characteristics of flow separations arising from boundary layers reattaching at design and off-design conditions. The results show that the unsteady numerical results are in good agreement with the experimental data. Additionally, hydraulic performance with and without the reattachment modification is similar throughout entire flow region whereas the respective flow characteristics for each impeller component are considerably different, especially at low-flow-rate conditions.