Effect of the relative radial position of the flow components on the exchange flow characteristics of a regenerative flow pump

Regenerative flow pumps (RFPs) are widely used in applications requiring high head and compact design, yet their hydraulic efficiency is often limited by complex internal flow losses. To address this issue, a systematic study on the influence of the radial position of flow components is essential for performance optimization. In this paper, five RFPs with flow components at different relative radial positions are designed and the influence on the internal flow and energy exchange characteristics inside the pump is investigated by theorical method, numerical simulation and experimental validation. A position coefficient P_r is proposed to quantify the relative radial position of the flow components. The results show that the RFP’s head and hydraulic efficiency are improved with the increase of P_r. In the models with larger value of P_r, the pressure’s growing speed is faster, and the high-velocity and low-velocity regions are distributed regularly. The distribution of the Ω-vorticity is corresponded with the exchange flow between the impeller and channel. However, in the models with smaller value of P_r, the mess distribution of the velocity and pressure in the flow regions induces the formation of adverse secondary flow and flow blockage, which leads to weak exchange intensity. Further, the energy loss in the RFP, measured by a dimensionless parameter E S , is gradually decreased as the value of P_r increases, which illustrates that the effective work accounts for a large proportion and the high efficiency is achieved when P_r is large.