Heat Source

This node describes heat generation within the domain. You express heating and cooling with positive and negative values, respectively. Add one or more nodes as needed — all heat sources within a domain contribute to the total heat source.

The node adds a source term Q to the right-hand side of the heat equation:

Specify Q0 as the heat rate per unit volume, as a linear heat source, or as a heat rate.

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 Q0 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 Q0 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 take into account 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.

Heat Source

Select an option from the list:

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For (default) enter a value for the distributed heat source Q0 when the default option () is selected. See also Additional General Source Options to use predefined heat sources available from other interfaces.

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For enter a value for the qs used in the predefined linear expression. The advantage of writing the source on this form is that it can be accounted for in the streamline diffusion stabilization. The stabilization applies when qs is independent of the temperature, but some stability can be gained as long as qs is only weakly dependent on the temperature.

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For enter a value for the heat rate P0. In this case Q0 = P0⁄V, where V is the total volume of the selected domains.

Additional General Source Options

For the general heat source Q0 there are predefined heat sources available (in addition to a heat source) when simulating heat transfer together with electrical or electromagnetic interfaces. Such sources represent, for example, ohmic heating and induction heating. Depending on additional physics interfaces, the following are available:

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With the addition of an Electric Currents interface, the heat source is available from the list.

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With the addition of any version of the Electromagnetic Waves interface (which requires the RF Module), the and heat sources are available from the list.

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With the addition of a Magnetic Fields interface (a 3D component requires the AC/DC Module), the heat source is available from the list.

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With the addition of a Magnetic and Electric Fields interface (which requires the AC/DC Module), the heat source is available from the list.

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For the Heat Transfer in Porous Media interface, with the addition of interfaces from the Battery Design Module, Corrosion Module, Electrodeposition Module, or Fuel Cell &Electrolyzer Module, heat sources from the electrochemical current distribution interfaces are available.

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Handling Frames in Heat Transfer

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Stabilization Techniques in the COMSOL Multiphysics Reference Manual


	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.


	For the definition of a localized heat source, see Line Heat Source, Line Heat Source and Point Heat Source. For the definition of a heat on a boundary, see Boundary Heat Source.


	Forced Convection Cooling of an Enclosure with Fan and Grille: Application Library path Heat_Transfer_Module/Power_Electronics_and_Electronic_Cooling/electronic_enclosure_cooling


	For a detailed overview of the functionality available in each product, visit https://www.comsol.com/products/specifications/

Location in User Interface

Context Menus

Ribbon

Physics tab with interface as , or any version of the Heat Transfer interface selected:

Physics tab with or selected in the model tree: