Numerical study of the effects of dissolved gas release in cavitating flow

Formation of vapor and air bubbles in hydraulic liquids can lead to significant degradation of the performance and lifetime of hydraulic systems. Vapor bubbles and cavities are generated due to phase transition. Formation of air and vapor-air bubbles takes place due to diffusion of dissolved gas molecules through the bubble interfaces. The goal of the present study was to formulate a mathematical model of dissolved gas diffusion process in high-speed unsteady liquid flows with cavitation. The proposed model is based on consideration of diffusion driven by the gradients of the dissolved gas concentration both in pure liquid and in liquid-vapor mixture. Convective transport of the dissolved and released gas is also taken into account. The formulated model was applied to the problem of cavitating flow in a planar throttle. The obtained results demonstrate that the dissolved gas release into vapor cavities significantly impact on the two-phase system behavior.