Radiative Heat Transfer
Heat transfer by radiation.
blockType: AcausalFoundation.Thermal.Elements.Radiation
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Description
Block Radiative Heat Transfer It is a transfer of heat by radiation between two bodies. The process is described by the Stefan—Boltzmann law:
where
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— heat flow;
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— the radiation coefficient;
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— surface area;
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and — temperatures of two bodies .
The radiation coefficient is determined by the geometric shapes, dimensions, and radiation coefficient of the surface. For example, the radiation constant for heat exchange between two parallel plates is calculated as:
where
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— the Stefan—Boltzmann constant;
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— the radiation coefficient of the surface of the emitting plate;
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— the radiation coefficient of the receiving plate surface.
Similarly, the emission coefficient for concentric cylinders is determined by the formula
where and — radii of the emitting and receiving cylinders, respectively.
A and B are thermal ports corresponding to different bodies. Since the positive direction of the block is from port A to port B, the heat flow is positive if it flows from A to B.
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.
Parameters
Parameters
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Area —
heat exchange area
m^2 | um^2 | mm^2 | cm^2 | km^2 | in^2 | ft^2 | yd^2 | mi^2 | ha | ac
Details
Heat exchange area.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Radiation coefficient —
coefficient of heat transfer by radiation
W/(m^2*K^4) | Btu_IT/(hr*ft^2*deltadegR^4)
Details
The coefficient of heat transfer by radiation between two bodies, based on their geometric shape, size and surface radiation coefficient.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |