Effect of stationary diffuser size on performance and pressure field characteristics of an axial-flow pump in pump mode

The axial flow pump (AFP) application in water irrigation and flood prevention systems is used widely worldwide. Therefore, improving the efficiency of AFP in the supply and demand of clean energy plays a vital role. In this paper, the influence of stationary diffuser size on the pump performance, flow uniformity at the outlet channel and pressure field is studied. So, a model of AFP, experimentally tested, and the unsteady flow uniformity and the pressure characteristic of the models are simulated in Ansys fluent CFD based on the k-epsilon turbulence model. The flow rate on both symmetrical outlet-channel for five different stationary diffuser sizes was analyzed, velocity distributions along the model were obtained, and vortex around the stationary diffuser and the frequency of pressure fluctuation were analyzed. The result showed when the stationary diffuser length is 1902.66 mm and thickness is 61.54 mm, the flow regime in the outlet pipe is so uniform, efficiency of the system enhance and pressure pulsation amplitude was minor; few vortexes appeared on the stationary diffuser and at the outlet canal, which causes to enhance the efficiency of the system.