Numerical investigation of oil droplet detachment from wall surface by a microbubble using ternary phase-field model

In this study, we investigated the detachment of an oil droplet from a wall surface by microbubbles (MBs) using the numerical simulation of a gas-liquid-liquid three-phase flow based on a phase-field model. A single MB was collided with an oil droplet adhered to a wall surface to determine whether the droplet would detach from the wall. It was confirmed that the oil droplet detached from the wall when the interfacial tension between the water and oil or between the bubble and oil was low. To clarify the mechanism, we theoretically calculated the balance of interfacial tension at the three-fluid contact line. The lower the interfacial tension between the water and oil and between the bubble and oil, the smaller the contact angle of the oil droplet on the bubble. This increased wettability was the driving force that caused the oil droplet to detach from the wall surface.