Radiative Heat Rate
This feature models a node (one-port component) of the thermal system, at which a heat rate due to surface-to-ambient radiation is prescribed.
Node Connections
Set the Node name for the radiative heat rate node.
Node Parameters
The heat rate P due to radiation on a diffuse-gray surface from the ambient surrounding is:
where σ is the Stefan-Boltzmann constant, ε is the emissivity of the surface, A is the area of the surface, Tamb is the ambient temperature, and T is the surface temperature.
In the thermal system, the corresponding heat rate applied on the selected node can be expressed in function of the difference between the ambient temperature, Tamb and the node temperature, T, by mean of the radiative thermal resistance, Rrad:
where
First, set the surface Area A. Then, select any material from the Material list to define the Surface emissivity ε From material. For User defined enter a value or expression.
Finally, set the Ambient temperature, Tamb. For User defined, enter a value or expression. Else, select an Ambient temperature defined in an Ambient Properties node under Definitions.
Initial Values
Set a user defined value or expression for the Initial temperature, Tinit, to be used at initialization, in particular to evaluate the surface emissivity.
Results
Select appropriate options in the Add the following to default results in order to include the following global variables (space-independent) in the default plots:
Heat rate
Temperature
Location in User Interface
Context Menus
Ribbon
Physics tab with Lumped Thermal System selected: