Evaporation is often known as the removal of moisture from the soil or capillary porous media. Evaporation in porous media is an important process in food and paper industry among others. Many physical effects must be considered: fluid flow, heat transfer and transport of participating fluids and gases. All of these effects are strongly coupled and predefined interfaces can be used to model these effects with COMSOL Multiphysics. Considering an unsaturated porous medium requires adjustments of the predefined equations. In this study, the changing water saturation inside the porous medium is computed. In contrast to the situation with a stationary liquid phase where the interfaces provided by COMSOL can be used as they are, the implementation of a multiphase flow requires some changes. This model and the instructions are based on the corresponding model and focus on the additional steps required to implement multiphase flow in porous media together with evaporation from liquid to gaseous phase.
