Variable Thermal Resistance
Variable thermal resistance.
blockType: AcausalFoundation.Thermal.Elements.VariableResistance
|
Path in the library: |
Description
Block Variable Thermal Resistance It allows modeling the time-varying heat transfer process in generalized terms, regardless of whether it is carried out by thermal conduction, convection, radiation, or a combination of both. Thermal resistance is an abstract quantity that combines thermal conductivity, convection, and thermal radiation. The thermal resistance of this unit varies according to the input scalar signal on the R port.
Heat transfer equation for the thermal resistance unit:
where
-
— thermal resistance;
-
— heat flow;
-
— the temperature difference between the layers.
Thermal resistance is related to other heat transfer values as follows:
where
-
— the distance between the layers, that is, the thickness of the material;
-
— the cross-sectional area perpendicular to the direction of the heat flow;
-
— thermal conductivity of the material;
-
— coefficient of convective heat transfer;
-
— the radiation coefficient;
-
and — temperatures at ports A and B respectively.
Variables
Use the parameter group Initial Targets to set the priority and initial target values for the block parameter variables before modeling. For more information, see Configuring physical blocks using target values.
Ports
Conserving
#
A
—
layer
heat
Details
Thermal port corresponding to the layer .
| Program usage name |
|
#
B
—
layer
heat
Details
Thermal port corresponding to the layer .
| Program usage name |
|
Input
#
R
—
the value of thermal resistance, K/W
scalar
Details
The input signal setting the value of thermal resistance.
| Data types |
|
| Complex numbers support |
I don’t |
Parameters
Parameters
#
Minimum thermal resistance —
minimum allowable value of thermal resistance
K/W
Details
If the input scalar signal falls below this value, the resistance remains at this value.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |