Flow performance analysis on shutoff condition in centrifugal pump based on CFD simulation

CFD simulations on flow field of centrifugal pumps at shutoff are generally performed by means of minor-flow assumption, which are different from real operating conditions and hard to well predict pump performances at shutoff. In this paper, therefore, the zero-flow boundary condition was taken to proceed to a numerical simulation of unsteady flow for the type IS125 centrifugal pump. The pump performances were predicted and verified by the pump performance test. The numerical result shows that there are different distributions of flow field and hydraulic load in the impeller channels, leading to the serious fluctuations of pumps performance. At the shutoff, the volute tongue suffers from the most serious flow impact among all operating conditions. It is also found that the channels of the impeller near the upstream of volute are water-discharging, but the channels of the impeller near the downstream of volute are water-inhaling. These results indicate that impeller channels have different flow ability while rotating at different positions. The numerical method and results can be benefit and referred for the operation and the design of centrifugal pumps.