Study of drying process a vertical porous channel by developing a numeric solver in OpenFOAM

Abstract

In this study, the phenomenon of evaporation in a porous medium of a vertical channel is analyzed. Numerical simulations of the partial evaporation process of the water in porous channel is conducted using an In-house developed code. First, by adding the thermal phase change to the base solver, the solver containing the evaporation phenomenon was generated and then, considering the hydrodynamic and thermophysical characteristics of the porous region, the final solver was obtained. The Initial state of the system consists of a water phase and a porous medium made of copper particles. However, with the partial evaporation of water, the vapor phase appears as the second fluid phase. It was assumed that water and vapor are incompressible and incompatible and the phenomenon of evaporation occurs unevenly. The Volume of fluid method (VOF) governs the interface between phases and the Lee model was used to account for the mass transfer between liquid and vapor phases. For surface tension between phases, the continuous surface force method was considered. Comparison of simulation results with experimental results showed that the new solver could well estimate the evaporation rate in different sections of the channel. The characteristics of this flow were introduced by examining the distribution of water volume fractions, temperature variations, time evolution of the porous channel drying process, porosity, permeability and contact angle between fluid phases and wall.