Study of the performance and internal flow in centrifugal pump with grooved volute casing

An innovative structure of longitudinal grooves was designed on the volute casing of a centrifugal pump to improve the performance and internal flow characteristics. Comparisons were made between the model with grooved volute casing (GVC) and the model with original volute casing (OVC) operating in different working conditions. To get a better understanding of the influence of grooves on the centrifugal pump, some preliminary studies were performed with a simplified model. The results indicated that the application of GVC offers better pump performance under the large flow rate, also can stabilize the operating range of the centrifugal pumP. In addition, the drag reduction effect of GVC is quite considerable compared with the pump with OVC. The pump with modified volute casing can suppress and eliminate the instability flow inside the impeller channels and volute casing. By using the GVC, the pressure and velocity distribution inside the impeller channel ameliorated especially for the 0.85 Ri near the region of rotor-stator interaction between impeller and volute casing. Furthermore, the effects of GVC on flow passing ability may be recognized clearly for the flow area of the model with GVC increased by 5% at one impeller channel compared to the pump with OVC.