Effect of injector on the inlet flow performance of multi-stage compound impeller structural centrifugal pump

This paper aims to improve the inlet flow performance of the centrifugal pump with multi-diversion compound impeller structural, the ejector was used to decrease the secondary vortex flow characteristics and improve boosting capability of the centrifugal pump. This paper presents the numerical simulation study on multi-diversion compound impeller structural centrifugal pump by using CFD method under three kinds of flow conditions. Numerical simulation results showed that the pressure and velocity magnitude distributions were complex in the ejector. The most violent velocity and pressure magnitude were occurred at the interface of the ejector with the pump inlet and the interface of volute. The inner pressure of the ejector was gradually increased from the interface of volute to ejector guide pipe. The highest pressure area was formed in the interface of the ejector guide pipe and a secondary vortex flow characteristics were appeared in a certain small area at the interface of the volute. The velocity was gradually decreased in the increasing pressure area and the flow field distribution of velocity and pressure magnitude trends to be same in the ejector. Low-speed flow clusters were formed in the middle pipe of the ejector at the various flow conditions and low-speed flow clusters had a mass range in the large flow condition. The inlet pressure of the pump was promoted significantly by the ejector which showed that the ejector can improve the inlet flow performance of centrifugal pump effectively.