关键词: 气泡脱离, 润湿性, 数值模拟

Abstract: The detachment of bubbles from the substrate is of great significance for nucleate boiling and phase-change heat transfer. In this study, the two-dimensional axisymmetric model is built up using the Level Set method, and the bubble dynamics is obtained by considering buoyant force, viscous force, inertial force, and surface tension in terms of non-dimensional parameters. The effects of Reynolds numbers, Bond numbers, and surface wettability on the bubble detachment from the substrate are revealed, and the critical parameters for bubble detachment are also obtained. We find that, with the increase in Reynolds number, the inertial force increases, leading to easy detachment of bubbles from the substrate. With the increase in Bond numbers, the bubble transits from the complete detachment to the partial detachment. With the decreases in surface wettability, the contact area between the bubble and substrate increases, leading to large interactive forces of the bubble with the substrate and the liquid near the contact area. Thus the bubble is difficult to detach from the substrate. These studies may be quite useful for the study of nucleate boiling heat transfer.

Key words: bubble detachment, wettability, numerical simulation