The Heat Transfer in Films (htlsh) interface (), found in the Thin Structures physics area under the Heat Transfer branch (), is used to model heat transfer by conduction, convection and radiation in layered materials represented by boundaries. The interface is active on all boundaries where a layered material is defined, with a Fluid model active by default. All functionalities for including other boundary contributions, such as surface-to-ambient radiation, are also available.

Although the layered material is represented as a boundary in the model, the through-thickness variation of the temperature is accounted for. It means that the convection-diffusion equation is solved also in the layered material’s thickness direction. In addition, a single boundary may represent several layers with different thermal properties varying through the thickness of the layered material. This uses the Extra Dimension tool which defines the equations on the product space between the boundary and the additional dimension for the thickness of the layered material. See Modeling Layered Materials for details.

For thermally thin boundaries, it is possible to bypass the use of the product space, by selecting Nonlayered shell in the Shell type list, and setting a user defined value for the Thickness Lth directly in the interface. A lumped formulation assuming that heat transfer mainly follows the tangential direction of the boundary is then available.

See Theoretical Background of the Different Formulations for a description of the different formulations.

When this version of the physics interface is added, these default nodes are also added to the Model Builder: Fluid, Thermal Insulation (an edge condition), and Initial Values. Then, from the Physics toolbar, add additional nodes that implement, for example, boundary interface or edge conditions, and heat sources. You can also right-click Heat Transfer in Films to select physics features from the context menu.

See Boundary Selection for a description this section, common to all versions of the Heat Transfer in Shells interface.

See Shell Properties for a description this section, common to all versions of the Heat Transfer in Shells interface.

See Physical Model for a description of the Reference temperature setting under the Physical Model section.

By default, the Heat transfer in porous media check box is not selected. Select it to make the Porous Medium boundary feature available.

This section is available by clicking the Show More Options button () and selecting Stabilization in the Show More Options dialog box. See Consistent Stabilization for more details.

This section is available by clicking the Show More Options button () and selecting Stabilization in the Show More Options dialog box. See Inconsistent Stabilization for more details.

See Discretization for more details.

By default, the shape functions used for the temperature are Linear. This setting affects also the discretization of the temperature field in the thickness direction.

See Dependent Variables for details.