Heat Source, Interface (Heat Transfer in Shells Interface)

This node models a heat source (or sink) on the exterior interfaces of a shell and, for the case of a layered shell, at the interfaces between its layers. It adds a heat source q = Qb or q = Pb ⁄ A. A positive q is heating and a negative q is cooling.

Interface Selection

Set the interfaces for which the heat source contribution should be applied. These can be internal interfaces between layers or the top and bottom surfaces. Select the applicable layers (the default setting is ) in the list. If no layered materials have been included yet, there is a shorthand available for creating a , a , or a (the plus, next to the setting).

For a , the heat source is applied on both sides by default. Unselect the and check boxes for another behavior. This setting has no effect unless the temperature differs from one side of the boundary to the other.

When a layered material stack or link is selected from the list, unselect the check boxes corresponding to layer interfaces where the node should not be applied in the table.

You can visualize the selected interfaces by clicking the and buttons.

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For a general description of layer and interface selections, see The Layer Selection and Interface Selection Sections.

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You can provide material parameters with a through-thickness variation by explicitly or implicitly using expressions containing the extra dimension coordinate as described in Using the Extra Dimension Coordinates.


	The desired selection for the node may correspond to boundaries with different layered materials. The All layered materials option allows to gather these materials to make the desired selection applicable for the node on the union of the boundaries where the layered materials are defined. See Layered Material, Layered Material Link, Layered Material Stack, Layered Material Link (Subnode), and Single Layer Material in the COMSOL Multiphysics Reference Manual.

Material Type

Select an option in the list to specify if the inputs of the section are defined in the material or spatial frame:

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The default option for the node is , which specifies that the heat source Qb is defined in the material frame. Because the heat transfer variables and equations are defined in the spatial frame, the inputs are internally converted to the spatial frame. See Conversion Between Material and Spatial Frames for details.

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The option defines Qb in the spatial frame. No frame conversion is needed.

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The option uses the option selected in the list of the section of the material applied on the domain on which the node is active.


	This option has no effect when the component does not contain a moving frame because the material and spatial frames are identical in such cases. With a Deformed Geometry or a Moving Mesh interface, the heat transfer features automatically account for deformation effects of the material and spatial frames on heat transfer properties. In particular the effects of volume changes on the density are considered. See Handling Frames in Heat Transfer and Material and Spatial Frames for details.

Boundary Heat Source

Click the (the default) or button.

For , enter the boundary heat source Qb. A positive Qb is heating and a negative Qb is cooling.

For enter the heat rate Pb. In this case Qb = Pb ⁄ A, where A is the total area of the selected layers interface.


	In 2D components, the equation contains an additional factor, dz, to account for the out-of-plane thickness. This is because the selected points correspond to edges in a 3D geometry.


	You can specify the source to be a harmonic perturbation in a frequency domain analysis. To mark the source as being a harmonic perturbation, right-click the node and choose Harmonic Perturbation. Note that this updates the node’s icon. See Theory for Harmonic Heat Transfer for more details.

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Theory for Heat Transfer in Thin Structures

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Handling Frames in Heat Transfer

Location in User Interface

Context menus

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Physics Tab with selected in the model tree: