서강대학교

초록/요약

Numerical simulation is performed for liquid evaporation, stick-slip contact line motion and particle deposition including line patterning in dip coating. The liquid–gas interface as well as the liquid–gas–solid contact line is tracked by a sharp-interface level-set method, which is extended to include the effect of phase change, to implement the contact angle model for the stick-slip contact line motion, and to treat the particle deposition on a moving substrate. The computations demonstrate that the particle deposition occurs spontaneously near the stationary contact line and the deposition thickness depends on the deposition rate constant and the substrate withdrawal velocity. The particle line formation is directly related to the stick-slip contact line motion. The effects of initial particle concentration, substrate withdrawal velocity, substrate temperature and contact angle on the particle line formation in dip coating are investigated. Second, Volume-of-Fluid (VOF) method, which is also track the liquid-gas interface, is developed for the film boiling of a hot plate in liquid jet impingement using the commercial code FLUENT. Numerical techniques for the film boiling in the fluid region as well as conduction in the solid region were incorporated into the VOF method using user-defined function code. The simulation results of film boiling in planar liquid jet were compared with the previous experimental numerical data. The numerical results have a similar trend to the experimental data.