Experimental and numerical research on the coupled mechanisms of cavitation effect in a Venturi-type bubble generator

Abstract

Venturi type bubble generator has a broad application in various fields and its bubble performance is closely related to the strong turbulent flow field. The interaction between bubble breakup and cavitation flow is not fully explained. In present work, the influence of cavitation on the suction performance and gas-phase transport pattern of a Venturi-type bubble generator is investigated by experiments and numerical simulations. The results show that the pressure ratio of 0.58 is the critical cavitation condition and the suction of the Venturi type bubble generator reaches the limiting value. The Venturi type bubble generator almost lost its suction capacity at the pressure ratio decreased to 0.27. However, the cavitation effect has a suppressive effect on the suction volume. The quasi-periodicity of the air inlet velocity pulsation and cavity development is highly consistent. Further research found that the blocking effect formed by return jets and pressure waves from cavity collapse is the main factor in reduced suction volume. The mechanisms of cavity shedding and collapse have a similar evolutionary model to the bubble breakup mechanisms in the Venturi-type generator.