Numerical study of vapor phase-diffusion driven sessile drop evaporation

The focus of this paper is the numerical study of vapor phase-diffusion driven sessile drop evaporation to study the evaporation flux profile along the interface of an evaporating sessile drop and its effect on the fluid dynamics inside the drop. The spatial variation of vapor phase concentration of the evaporating liquid is governed by the Laplace equation and the fluid dynamics is governed by Stokes equation. In this study, the numerical analysis and the mesh discretization method are described thoroughly. The time dependent evaporation dynamics, drop shape, and fluid dynamics are solved simultaneously. We compared the calculated velocity profiles to the result presented in the previous work [Widjaja, E., Liu, N., Li, M., Collins, R. T., Basaran, O. A., & Harris, M. T. (2007). Computers and Chemical Engineering, 31(3), 219–232] in the case of uniform evaporation flux along the drop interface. The two cases gave different results, which confirmed that fluid velocity profiles inside the drop are influenced by the evaporation flux profiles along the drop interface.