Evaluation of Rotor-Stator Interface Models for the Prediction of the Hydraulic and Suction Performance of a Centrifugal Pump

The effects of a rotor-stator interface model on the hydraulic and suction performance of a single-stage centrifugal pump have been evaluated. A three-dimensional Reynolds-averaged Navier-Stokes (RANS) analysis was performed using the shear-stress transport turbulence model. The cavitating flow was simulated using a homogeneous two-phase mixture model and a simplified Rayleigh-Plesset cavitation model. Three performance parameters were selected to compare different cases: the hydraulic efficiency, head coefficient, and critical cavitation number for a head-drop of 3%. Frozen-rotor and stage models were evaluated for the rotor-stator interface. The evaluation was done using three different computational domains: one with a single passage of the impeller with a vaneless diffuser, one with a single passage of the impeller with the whole shape of volute casing, and another with the whole passage of the impeller with the whole shape of volute casing. Two different volute shapes were also tested. The results show that it is desirable to use the whole domain of the impeller and volute with the frozen-rotor model for accurate prediction of the suction performance. The stage model is not recommended for the prediction of the suction performance of the centrifugal pump with the volute in severe off-design conditions.