Abstract: Three regenerative flow pumps with floating impeller(RFP), different in the thickness of inlet/outlet axial clearance, are designed. The SST k-ω turbulence model is employed in the numerical simulation of RFP’s inner flow characteristics. The external characteristics and full three-dimensional flow field of RFP with the impeller floating in different axial positions are calculated. The pressure distribution characteristics in each component and mass exchange mechanism in RFP are discussed, and the varying rules of the axial force exerting on the floating impeller is further revealed. The results show that the growth pattern of pressure in pump channel and axial clearance are consistent in three pump models, where the fluid flows from the flow development region to flow acceleration region and then enters into the stripper region. The flow in development region is not stable, but in acceleration region, the exchange flow between the impeller and channel is stable and sufficient. Besides, in stripper region, the flow pressure changes rapidly to prevent the flow leakage. Compared with the pump model C1J1 taking equal clearance thickness, the head and hydraulic efficiency of pump models C1J3 and C3J1 are relatively lower. Under the effect of the impeller deviation, the intensity of energy exchange between the impeller and channel is weaker, and the pressure growth rate on the monitoring points of each component is comparatively slow. Additionally, the axial force of impeller is related to the impeller’s floating position, and the impeller tends to deviate to the direction with larger thickness of axial clearance.

Key words: regenerative flow pump with floating impeller, inner flow characteristics, energy exchange, axial force, clearance thickness