Numerical study of droplet evaporation in contact with hot porous surface using lattice Boltzmann method

This paper presents a numerical simulation of a liquid droplet evaporation during penetration in a porous medium based on lattice Boltzmann method. The binary-fluid model of Lee, which is applicable to high density ratio, is combined with a passive scalar LB thermal model to simulate two-phase flow. A proper source term is incorporated at the phase interface, and the classical convective Cahn–Hilliard equation in the presence of phase change is employed in the multiphase LB framework of Lee. Effects of different non-dimensional parameters including the Archimedes number, the Bond number, the Stefan number, the Prandtl number, the porosity, contact angle and density ratio on the penetration of liquid inside the porous media and the droplet evaporation are investigated and temperature profiles, flow fields, mass source contours are analyzed. Increasing the Bond number, the Archimedes number and density ratio will decrease the penetration rate, and accelerates the evaporation. Also, increasing the Stefan number and porosity accelerate the evaporation, while increasing the Prandtl number leads reduction in evaporation rate.