Research on blade tip clearance cavitation and turbulent kinetic energy characteristics of axial flow pump based on the partially-averaged Navier-Stokes model

Abstract

To reveal the cavitation forms of tip leakage vortex (TLV) of the axial flow pump and the flow mechanism of the flow field, this research adopts the partially-averaged Navier-Stokes (PANS) model to simulate the cavitation values of an axial flow pump, followed by experimental validation. The experimental result shows that compared with the shear stress transport (SST) k - ω model, the PANS model significantly reduces the eddy viscosity of the flow field to make the vortex structure clearer and allow the turbulence scale to be more robustly analyzed. The cavitation area within the axial flow pump mainly comprises of TLV cavitation, clearance cavitation and tip leakage flows combined effect of triangular cloud cavitation formed. The formation and development of cavitation are accompanied by the formation and evolution of vortex, and variations in vortex structure also generate and promote the development of cavitation. In addition, an in-depth analysis of the relationship between the turbulent kinetic energy (TKE) transport equation and cavitation patterns was also conducted, finding that the regions with relatively high TKE are mainly distributed around gas/liquid boundaries with serious cavitation and evident gas-liquid change. This phenomenon is mainly attributed to the combined effect of the pressure action term, stress diffusion term and TKE production term.