Combined experimental and numerical analysis of cavitating flow characteristics in an axial flow waterjet pump

The objective of this paper is to apply experimental and numerical methods to investigate the cavitating flow characteristics in an axial flow waterjet pump. In the experiments, the hydraulic and cavitation performance of the waterjet pump model are tested under different operation conditions. In the numerical simulations, the Zwart cavitation model and the SST k-ω turbulence model are employed to simulate the cavitating flow. The results show that the cavitation process affects the structures of the attached cavitation on suction side (SS). As the pressure decreases continuously, the growth of the cavity on SS narrows the passage and changes the flow field. From the comparison of the induced velocity field (IVF) in four different cavitation numbers (i.e. σ₁ = 0.81; σ₂ = 0.74; σ₃ = 0.72; σ₄ = 0.70), the impact of the cavitation can be summarized as two patterns, namely the “In-Out” pattern and “In- Out-Back” pattern. The blade loading C_BL, which reflects the energy conversion ability, is found to be related to the cavitation process. The analysis of the upstream flow field near the leading edge (LE) demonstrates that the cavitation evolution has an influence on the incidence angle, which further interacts with the flow structures on SS.