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Home / Examples / Thermal Analysis [Watt] / Example 4: Block Containing Heating Element (Transient Analysis)
Example 4: Block Containing Heating Element (Transient Analysis)
General
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The model is the same as the example 3: A heating element is placed in a block; the ambient temperature is constant. This is a transient analysis.
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The temperature distribution and the heat flux vectors are solved under the transient condition.
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Unless specified in the list below, the default conditions will be applied.
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Obtain this session's project file. (Right-click and choose 'Save link as')
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Results will vary depending on Femtet version and the PC environment.
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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Solver |
Thermal Analysis [Watt] |
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Analysis Type |
Transient Analysis |
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Options |
N/A |
The transient analysis tab is set up as follows. The number of calculation steps is 120. The timestep is 2 sec.
Therefore, the temperature distributions for 240 sec are solved.
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Tab |
Setting Item |
Settings |
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Transient Analysis |
Table |
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Initial Temperature |
0 [deg] |
Model
The same as the example 3. The body attributes, the material properties and the boundary conditions are the same as well.
A cylindrical heat source (Nichrome) is placed in the center of a glass-epoxy block.
The heat quantity is set in the body attribute. The ambient temperature is set to 0[deg] in the external boundary condition.
Body Attributes and Materials
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Body Number/Type |
Body Attribute Name |
Material Name |
Mesh Size |
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0/Solid |
VOL1 |
006_Glass_epoxy * |
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1/Solid |
VOL2 |
109_Nichrome * |
2 |
* Available from the material DB
The heat quantity of VOL2 is set up as follows.
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Body Attribute Name |
Tab |
Settings |
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VOL2 |
Heat Quantity |
10 [W] |
Boundary Conditions
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Boundary Condition Name/Topology |
Tab |
Boundary Condition Type |
Settings |
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Outer Boundary Condition |
Heat |
Temperature |
0 [deg] |
To set Outer Boundary Condition, go to the [Model] tab
and click [Outer Boundary Condition] 
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Results
A cross section's temperature distributions in 40 sec, 160 sec and 240 sec are shown below.
In 40 sec
In 120 sec
In 240 sec
The temperature vs. time is plotted for the center of the heat source.
The temperature is stabilizing at around 250 deg in 240 sec.