Abstract:In order to investigate the flowing mechanism of cavitation in nozzle, a visualization test was designed to directly observe cavitation in nozzle holes. Mixed multiphase model, cavitation model and k-ε equation were used to simulate the twophase cavitation flow. The effects of injection pressure, bubble volume fraction in liquid, liquid viscosity, wall physical properties and surface tension on the cavitation flow in nozzle were investigated. The results show that the initial cavitation flow developed gradually to be super cavitation with the increasing of entrance pressure. When the cavitation parameter is lower than the critical cavitation parameter, the discharge coefficient increases with the increasing of cavitation parameter. However, on contrary condition, the change of discharge coefficient can be negative with no cavitation. The larger the bubble volume fraction in liquid is, the more obvious the cavitation is. With the increase of inlet pressure, the bubble volume fraction has more influence on cavitation with smaller critical cavitation pressure. The liquid viscosity has a certain restriction on cavitation development. Enhanced liquid viscosity needs high critical cavitation pressure. The wall physical properties and surface tension has slight impact on cavitation.