Surface-to-Ambient Radiation (Heat Transfer Interface)

Use this node to take into account radiation from boundaries to the ambient. The net inward heat flux from surface-to-ambient radiation is

where ε is the surface emissivity, σ is the Stefan-Boltzmann constant (a predefined physical constant), and Tamb is the ambient temperature.

Model Input

This section contains fields and values that are inputs for expressions defining material properties. If such user-defined property groups are added, the model inputs appear here.

Temperature

This section is available when material properties are temperature-dependent. By default, the temperature of the parent interface is used and the section is not editable. To edit the field, click (

). The available options are (default), (the minput.T variable, set to 293.15 K by default) and all temperature variables from the physics interfaces included in the model. To edit the minput.T variable, click the button (

), and in the node under , set a value for the in the section.

Radiation Settings

Define on which side of the boundary is the ambient domain that receives the radiation, by selecting a : or .


	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.

Surface-to-Ambient Radiation

Ambient Temperature

For , enter an Tamb. The default value is approximately room temperature, 293.15 K (20ºC). Else, select an defined in an node under .

Surface Emissivity

The default ε (a dimensionless number between 0 and 1) is taken . For , it should be specified. An emissivity of 0 means that the surface emits no radiation at all while an emissivity of 1 means that it is a perfect blackbody.

Location in User Interface

Context Menus

Ribbon

Physics Tab with interface as selected: