Boundary Heat Source
This node models a heat source (or heat sink) that is embedded in the boundary. When selected as a Pair Boundary Heat Source, it also prescribes that the temperature field is continuous across the pair. Note that in this case the source term is applied on the source side.
Pair Selection
If this node is selected from the Pairs menu, choose the pair on which to apply this condition. A pair has to be created first. See Identity and Contact Pairs in the COMSOL Multiphysics Reference Manual for more details.
Boundary Heat Source
Click the General source (the default) or Heat rate button.
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For General source enter a value for the boundary heat source Qb when the default option, User defined, is selected.
A positive Qb corresponds to heating and a negative Qb corresponds to cooling. For the general boundary heat source Qb, there are predefined heat sources available when simulating heat transfer together with electrical or electromagnetic interfaces. Such sources represent, for example, ohmic heating and induction heating.
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For Heat rate enter the heat rate Pb. In this case Qb = Pb ⁄ A, where A is the total area of the selected boundaries.
Frame Selection
The settings are the same as for the Heat Source node and are described under Frame Selection.
Source Position
To display this section, click the Show button () and select Advanced Physics Options.
Select a Source position to define a side where the heat source is defined: Layer (the default), Upside, or Downside. This setting has no effect unless the temperature differs from one side of the boundary to the other. Typically when Boundary Heat Source contributes with a Thin Layer feature.
To define the boundary heat source Qb as a function of the temperature, use the local temperature variable on the selected boundary, ht.bhs1.Tvar, that corresponds to the appropriate variable (upside, downside, or average temperature of a layer, wall temperature with turbulence modeling), depending on the model configurations. See Boundary Wall Temperature for a thorough description of the boundary temperature variables.
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.
Upside and downside settings can be visualized by plotting the global normal vector (nx, ny, nz), that always points from downside to upside. Note that the normal vector (ht.nx, ht.ny, ht.nz) may be oriented differently.
See Tangent and Normal Variables in the COMSOL Multiphysics Reference Manual.
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Handling Frames in Heat Transfer
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About the Heat Transfer Interfaces
Location in User Interface
Context menus
Heat Transfer>Boundary Heat Source
Heat Transfer in Solids>Boundary Heat Source
Heat Transfer in Fluids>Boundary Heat Source
Heat Transfer in Porous Media>Boundary Heat Source
Heat Transfer in Building Materials>Boundary Heat Source
Bioheat Transfer>Boundary Heat Source
Heat Transfer with Surface-to-Surface Radiation>Boundary Heat Source
Heat Transfer with Radiation in Participating Media>Boundary Heat Source
Heat Transfer in Solids>Pairs>Pair Boundary Heat Source
Heat Transfer in Fluids>Pairs>Pair Boundary Heat Source
Heat Transfer in Porous Media>Pairs>Pair Boundary Heat Source
Heat Transfer in Building Materials>Pairs>Pair Boundary Heat Source
Bioheat Transfer>Pairs>Pair Boundary Heat Source
Heat Transfer with Surface-to-Surface Radiation>Pairs>Pair Boundary Heat Source
Heat Transfer with Radiation in Participating Media>Pairs>Pair Boundary Heat Source
Ribbon
Physics Tab with interface as Heat Transfer, Heat Transfer in Solids, Heat Transfer in Fluids, Heat Transfer in Porous Media, Heat Transfer in Building Materials, Bioheat Transfer, Heat Transfer with Surface-to-Surface Radiation or Heat Transfer with Radiation in Participating Media selected:
Boundaries>interface>Boundary Heat Source
Pairs>interface>Pair Boundary Heat Source