Numerical simulation of the oil peeling mechanism on a hydrophilic plate dipping underwater

Peeling is a fundamental physical behavior involving the removal of foreign substances attached to a surface, and it finds applications in various engineering problems. Most previous studies have focused on peeling thin solid films from solid surfaces. However, ocean pollution has emerged as a serious environmental concern, making it critical to effectively and continuously remove highly viscous oil from oil recovery devices to prevent oil fouling. To address this, recent technological advancements have introduced an oil recovery technique that utilizes a hydrophilic surface capable of detaching, and even peeling, oil when dipped into water. In this study, we analyzed the underlying peeling mechanism by numerically simulating the oil peeling process from a vertically situated dipping plate with hydrophilic treatment. The present work expanded the level contour reconstruction method, originally developed for two-phase interface tracking, to handle the three-phase flow involved in the peeling of oil attached to the plate by an air-water meniscus. We properly validated the proposed numerical model and investigated the effects of various input conditions, including oil thickness, descending plate speed, and oil viscosity, in detail. Furthermore, force analysis during the oil peeling process was performed, and a regime map is provided to offer a comprehensive understanding of the overall peeling process. This research aims to contribute to the development of efficient and reliable oil recovery methods, particularly in combating ocean pollution caused by viscous oil residues.