The Heat Transfer in Porous Media interface (), found under the Heat Transfer branch () when adding a physics interface, is used to model heat transfer by conduction, convection, and radiation in porous media. A Porous Medium model is active by default on all domains. All functionality for including other domain types, such as a solid domain, is also available.

The temperature equation defined in porous media domains corresponds to the convection-diffusion equation with thermodynamic properties averaging models to account for both solid matrix and fluid properties. This equation is valid when the temperatures into the porous matrix and the fluid are in equilibrium. If not, use The Local Thermal Non-Equilibrium Interface instead.

The physics interface is an extension of the generic Heat Transfer interface. When this physics interface is added, the following default nodes are added in the Model Builder: Porous Medium, Thermal Insulation (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 Heat Transfer in Porous Media to select physics features from the context menu.

The capability to define material properties, boundary conditions, and more for porous media heat transfer is activated by selecting the Heat Transfer in Porous Media check box (see Figure 5-1).

This check box is selected by default when adding The Heat Transfer in Porous Media Interface.

When the Subsurface Flow Module is added, under Physical Model, select Extended from the Porous matrix model list to use a version of the matrix feature to account for multiple immobile solids and fluids, as well as for geothermal heating.