Numerical model for liquid droplet motion on vertical plain-fin surface

In order to predict the performance of tube-finned heat exchangers under dehumidifying condition and to optimize the fin geometries, the behavior of a liquid droplet on vertical plain-fin surfaces needs to be investigated. The objective of this article is to develop a model for liquid droplet motion on vertical plain-fin surfaces. To achieve this goal, the mechanism of droplet motion is analyzed. The volume of fluid-continuous surface force method, with the contact angles of droplet being specified, is employed to simulate the liquid droplet motion. The sub-model for calculating varying contact angles of droplet under the interactions of gravitation, surface tension and airflow force is obtained based on the analysis of the acting forces. The prediction was verified by experimental data and verification results show that the relative deviations of minimum contact angle and velocity are within 0.4%∼1.8% and 5.7%∼10.0%, respectively.