The Moisture Transport in Solids Interface
The Moisture Transport in Solids (mts) interface () is used to model moisture transport in the pores of a porous medium, through convection and diffusion of vapor in moist air, and convection and capillary flow of liquid water. A Porous Medium model is active by default on all domains.
The water conservation equation defined in porous media domains corresponds to the convection-diffusion equation for the total moisture content. This equation is valid when the amount of water in vapor phase and in liquid phase are in equilibrium, which corresponds to the saturation conditions. An additional equation is solved for the transport of dry air to account for changes in the moist air pressure.
When this physics interface is added, these default nodes are added to the Model Builder: Porous Medium, No Flux (the default boundary condition), and Initial Values. Then, from the Physics toolbar, add other nodes that implement, for example, boundary conditions. You can also right-click Moisture Transport in Solids to select physics features from the context menu.
By default, the shape functions used for the relative humidity and the moist air pressure are Quadratic.
See The Moisture Transport in Solids Interface in the Porous Media Flow Module User’s Guide for details.
Theory for Moisture Transport in Solids