The Local Thermal Nonequilibrium 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 for which the solid and fluid phase temperatures are not in equilibrium. A
Porous Medium model is active by default on all domains, with
Porous medium type set to
Local thermal nonequilibrium. All functionality for including other domain types, such as a solid domain, is also available, and surface-to-ambient radiation may be considered.
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.
In the heat source features available under the Fluid and
Porous Matrix subnodes, the user input corresponds to the heat production per total unit volume. It is multiplied by the volume fraction of each phase and added into the corresponding heat equation.
In the heat flux features available under the Fluid and
Porous Matrix subnodes, the user input corresponds to the heat flux per total unit surface. It is multiplied by the volume fraction of each phase and added into the corresponding heat equation. The surface fraction is approximated by the volume fraction.