Surface-to-Ambient Radiation (Heat Transfer in Thin Shells Interface)
Use this node to add surface-to-ambient radiation to edges of a thin shell. 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.
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.
Surface-to-Ambient Radiation
Surface emissivity
The default Surface emissivity ε (a dimensionless number between 0 and 1) is taken From material. For User defined, 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.
Ambient temperature
For User defined, enter an Ambient temperature Tamb. Else, select an Ambient temperature defined in the Ambient Settings section of a Heat Transfer or Heat Transfer in Shells interface.
In 2D, the equation has an additional factor, dz, to account for the out-of-plane thickness.
Theory for Heat Transfer in Thin Structures
Location in User Interface
Context menus
 Heat Transfer in Thin Shells>Surface-to-Ambient Radiation
 Heat Transfer in Thin Shells>Pairs>Surface-to-Ambient Radiation
Ribbon
Physics Tab with Heat Transfer in Thin Shells selected:
Support>Heat Transfer in Thin Shells>Surface-to-Ambient Radiation
Pairs>Surface-to-Ambient Radiation
with Support as Egdes in 3D and Points in 2D.