The Heat Transfer in Packed Beds interface (), found in the Porous Media physics area under the Heat Transfer branch () when adding a physics interface, is used to model heat transfer by conduction and convection, in porous media where the local thermal equilibrium is not assumed between the solid pellets of a packed bed and the fluid phase, and where the radial variation of the temperature due to conduction inside the pellets is accounted for. A Porous Medium model is active by default on all domains, with Porous medium type set to Packed bed. All functionality for including other domain types, such as a solid domain, is also available, and surface-to-ambient radiation may be considered, assuming that radiation effects are handled on the exterior surface of the pellets only.

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) overridden by Local Thermal Nonequilibrium Boundary (showing all the boundaries adjacent to domains where two temperatures are solved for solid and fluid phases), and Initial Values.

Specific subnodes are also present by default under the Fluid and Pellets subnodes of the Porous Medium node:

Other subnodes implementing boundary conditions specific to the fluid and pellets may be added, to model flow conditions, heat sources, fluxes, and phase change. This can be done by right-clicking Fluid or Pellets to select physics features from the context menu.

By default, the shape functions used for the temperature in porous media are Linear.