CAE Software【Femtet】Murata Software Co., Ltd.
Example6 Heat Radiation by Natural Convection(Transient Analysis)
General
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The model is the same as Exercise 5: The heat radiation from an aluminum plate is analyzed. This is a transient analysis.
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The temperature distribution and the heat flux vectors are solved.
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Unless specified in the list below, the default conditions will be applied.
Analysis Space
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Item |
Settings |
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Analysis Space |
3D |
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Model unit |
mm |
Analysis Conditions
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Item |
Settings |
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Solvers |
Thermal Analysis [Watt] |
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Analysis Type |
Transient analysis |
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Options |
N/A |
The transient analysis is set up in transient tab as follows. The total number of steps is 30. The time step is 10 second.
Therefore, the temperature distributions for 300 seconds are solved.
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Tab |
Setting Item |
Settings |
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Transient analysis |
Table |
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Initial Temperature |
25[deg] |
Model
The same as Exercise 5. The material properties and the boundary conditions are the same as well.
Aluminum plate, defined by a rectangular solid body, is placed vertically. The bottom face is set with the Temperature boundary condition.
The other faces are set with the Heat transfer/Ambient radiation boundary condition.
Body Attributes and Materials
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Body Number/Type |
Body Attribute Name |
Material Name |
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0/Solid |
VOL1 |
404 Pure-Al1100 * |
* Available from the Material DB
Boundary Conditions
The coefficient for the natural convection is calculated as follows. See [Heat Transfer/Ambient Radiation] for more information.
The coefficient can be calculated automatically if that is preferred.
2.51×C×（1/L)＾（1/4） = 2.50 [W/m2/deg5/4]
where
C = 0.56
L = 0.1
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Boundary Condition Name/Topology |
Tab |
Boundary Condition Type |
Settings |
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Temp/Face |
Thermal |
Temperature |
80[deg] |
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Outer Boundary Condition |
Thermal |
Heat Transfer/Ambient Radiation |
Natural convection: 2.50[W/m2/deg5/4] Room Temperature : 25[deg] |
Results
The temperature distributions in 20 sec, 60 sec and 120 sec are shown below.
At Minimum/Maximum Value on the Contour tab of [Graphics Setup], deselect “Automatic” and set 25 => 80.
In 20 seconds
In 60 seconds
In 120 seconds
The heat creeps up as the time goes by.
The chart below shows the temperature of the tip of the plate.
It is getting stabilized in 200 seconds.