A numerical model for partially-wetted flow of thin liquid films

Abstract

A model for simulating thin liquid film transport over solid surfaces has been developed. The film transport for mass continuity and momentum were formulated as a two-dimensional set of equations using thin-film assumptions. These equations have been implemented in an open-source CFD code (OpenFOAM). Treatments for partial-wetting phenomena have been included in the model to account for the behavior near the contact-line. A surface-tangential force along the contact line has been developed to allow for the simulation of rivulets and dry patches in two-dimensional surface flow. An approach for applying contact angle effects to the model for a real stochastic surface is outlined. Additionally, experimental measurements were made for film flow over an inclined surface for a wide range of flow rates. Using these experimental results, the model has been validated for partially wetted flow over an inclined panel. The critical flow rate of a film over a given surface was used as validation for the model. Results show that for flow rates below the critical flow rate, the partially wetted behavior of the flow was reproduced. Comparisons to experimental flow patterns and wetted-area fractions were made.