Radiative Thermal Resistor
This feature models a two-port passive component of the thermal system. It connects two nodes, by creating a difference in the temperatures of its two connecting ports. It models heat loss by surface-to-surface radiation in a domain.
It adds equations for the heat rates Pp1 and Pp2 and the temperatures Tp1 and Tp2 at the connecting ports p1 and p2 of the component, and defines the following relation between the heat rate P and the temperature difference ΔT:
where R (SI unit: K/W) is the radiative thermal resistance, which is defined to account for radiative heat transfer between two opaque diffuse gray surfaces in an enclosure.
See Theory for the Radiative Thermal Resistor Component for details about the underlying theory.
Identifier
Enter a Component name for the radiative thermal resistor. The prefix is RR.
Node Connections
Set the two Node names for the nodes connected by the radiative thermal resistor.
Component Parameters
Select a Radiation type for the surfaces. By default, Blackbody radiation is assumed, which sets ε1=ε2=1 in the expression of the radiative thermal resistance R. When the Radiation type is Graybody radiation, select any material from the Material lists to define the Surface emissivity ε1and Surface emissivity ε2 From material. For User defined enter values or expressions.
Select a Surface configuration from the following options:
User defined (default): specify the View factor, F12, and the Area of surface 1, A1, used in the expression of the radiative thermal resistance.
Large (infinite) parallel planes: specify the Area of surface 1, A1, used in the expression of the radiative thermal resistance. In this configuration, F12=1.
Long (infinite) concentric cylinders: specify the Height of the cylinders, H, the Radius of the Inner cylinder, r1, and the Radius of the Outer cylinder, r2, used in the expression of the radiative thermal resistance. In this configuration, F12=1.
Concentric spheres: specify the Radius of the Inner sphere, r1 and the Radius of the Outer sphere, r2, used in the expression of the radiative thermal resistance. In this configuration, F12=1.
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 at node 1
Temperature at node 2
Location in User Interface
Context Menus
Ribbon
Physics Tab with Lumped Thermal System selected: