Multiphase CFD Modelling and Simulation of Evaporation from Porous Medium

Abstract

Evaporation of liquids from porous media appears ubiquitously in nature and technical applications. Evaporation from the soil, drying of foods, drying of building materials and baking are some crucial examples. In general, it is a coupled process where the evaporation occurs at the interface of the porous media, which is exposed to a free flow region. In the coupled process, various physical effects occur simultaneously. The key processes influencing evaporation are the transport of liquids through porous media, pore structure, heat transfer and coupling with the boundary. Computational Fluid Dynamics (CFD) methods can be employed to improve the understanding of the effects of evaporation from porous fluid reservoirs. To develop mathematical models to study such effects, suitable coupling methods are needed. In this study, the one-domain coupling method has been utilized to study the effects of the porous medium on the evaporation of multi-phase liquids. One-domain coupling method needs a single governing equation applicable to porous and free-flow regions. In this study, the CFD method has been utilized to analyse the rate of evaporation from a porous media as a function of temperature, heat transfer, inlet free-flow velocity, the saturation of multi-species liquids, and the porous medium structure. The obtained data for evaporation in the case of the porous media is validated against the model with a direct liquid interface with no porous media. Hence, a quantitative estimation of the evaporation of different components has been put forward.