Abstract:The dynamic cavitation model of airwatertwophase flow was established according to the time variation of airprecipitation and digestion process in water

which was used in FLUENT threedimensionnumerical simulation to simulate the airwater twophase flow

and the variationlaw of venturi tube throat diameter、inlet pressure and tandem venturi on vaporvolume fraction were obtained The results of numerical simulation andexperiments show that the vapor volume fraction increases with pressureincreasing，Butnot infinitely increasing

there are limits;As the throat diameter increases

the cavitation effect of the venturi tube gradually decreases;Under the sameconditions

the cavitation effect of the tandem venturi is not as good as thecavitation effect of a single venturi

that is

the twostage cavitation cannotbe realized by the tandem venturiThe above research is of great significance tothe engineering application of venturi tubes