Simulation of Substrate Cooling during Evaporation of Pure Vapor from the Surface of a Thin Liquid Film and Droplets

Abstract

A numerical study of the process of cooling a substrate under the conditions of evaporation of pure vapor from the surface of a liquid film and droplets was carried out. The lattice Boltzmann method was used for modeling such a two-phase system taking into account the thermal conductivity of the substance and the evaporation. We used the van der Waals equation of state describing the liquid–vapor phase transition. A new method is proposed for setting the boundary conditions on a flat surface for modeling the contact wetting angles in the lattice Boltzmann method. The latent heat of phase transition is taken into account. It is shown that the process depends on the film thickness and the rate of vapor removal from the film surface. The cases of forced outflow of vapor, as well as the method of vapor condensation on a cooled condenser are considered. It is shown that the heat flux from the substrate increases sharply in the vicinity of the droplet contact lines. A comparison is made of the heat fluxes during the evaporation of the film and droplets on substrates with different wettabilities.