Numerical investigation of submerged cavitation jet based on stress-blended eddy simulation

Cavitation jet technology is extensively applied in fields such as mechanical processing, rock fragmentation, and energy development. To deeply understand the motion characteristics of the submerged jet and evaluate the influence mechanism of cavitation number on cavitation characteristics, the factors of boundary conditions, grid size, and turbulence model were taken into account. In this study, based on CFD numerical simulation technique, the SBES turbulence model was used to analyze the evolution mechanism of the cavitation cloud and the effects of time and jet pressure on the cavitation characteristics. The results show that the SBES turbulence model can better capture the small-scale turbulent details in jet flow and predict the shedding phenomenon of the cavitation cloud downstream. Moreover, when the downstream cavitation cloud collapses, a local high pressure of very short duration is generated and transmitted around, which affects the morphology of the cavitation cloud at the nozzle outlet. And the increase of the jet pressure has a positive effect on the length of the outlet bubble, the vapor volume fraction of the shed cavitation cloud, and the number of small bubbles generated at the gas-water interface at the tail of the cavitation cloud. Besides the effect of cavitation number on the cavitation characteristic of the jet is mainly in the early stages of cavitation, while the effect in the later stages of development is weak. The research can provide theoretical reference for improving nozzle structure and selecting working parameters to improve cavitation performance in engineering applications.