Numerical Analysis of Microbubble Rising in an Oil–water Liquid Layer under Gravity Based on Three-phase Field Method

In this paper, we conduct two-dimensional simulations based on three-phase field method to analyze the bubble rising behaviors in an oil–water liquid layer. During the rising process, if the inertial force is higher than the combined effect of interfacial tension and viscous force, the bubble will deform and successfully pass through the oil–water interface, otherwise, it will be trapped by the fluidic interface. And the microbubble will carry some water fluid into the oil phase when it passes through the oil–water interface. The effects of various factors including bubble diameter, liquid density, interfacial tensions, fluid viscosity and non-Newtonian properties of fluids on single bubble rising, deformation and entrainment are systematically studied. What’s more, the rising behaviors of two closely distributed bubbles are further analyzed. These conclusions can help to understand the mechanism of bubble rising in an oil–water liquid layer under gravity and give useful guidelines for those applications concerning bubble rising such as the flow boiling for heat sink in space science.