Influence of the channel inclination on the exchange flow and vorticity transport characteristics in a regenerative flow pump

To enhance the overall performance of regenerative flow pump (RFP) to achieve efficient and stable operation over a broad range, this paper employs numerical simulation to study the internal flow conditions of RFP models with three different inclination coefficients (I-c = -0.25, Ic = 0, I-c = 0.25). The analysis focuses on the pressure distribution, energy exchange, velocity variation, and vorticity distribution characteristics within the impeller and channel. The comparison indicates that at I-c = -0.25 with an outward channel, the flow within the pump is stabilized, and the rate of pressure growth and exchange intensity are increased. When I-c = 0 with a semi-circular channel and I-c = 0.25 with an inward channel, there are narrower flow space at the channel's outer diameter, impeding effective fluid motion along the channel and inducing chaotic flow. This condition escalates flow losses and adversely affects the hydraulic performance of the RFP. Additionally, the analysis based on the vorticity transport equation reveals that the Coriolis force term significantly contributes to the generation and transport of vortex in the impeller, while the vortex stretching term dominates the transport of vortex in the channel.