FEM ConstraintBodyHeatSource

Description

Defines an internally generated body heat given in W/kg.

1.0 and above: Can also define the heat source in W.

Heat sink with a chip underneath serving as a body heat source

Usage

1. There are several ways to invoke the command:
   • Press the Body Heat Source button.
   • Select the Model → Thermal Boundary Conditions and Loads → Body Heat Source option from the menu.
2. 0.21 and above: Press the Add button. For a 3D analysis, select a 'solid' (body) from your model, for a 2D analysis select a face. introduced in 1.1: To remove objects from the selection, press the Remove button.
3. Set the value:
   • 0.20 and below: Since the tool has no task dialog, use the Property View and set the property DataHeat Source.
   • introduced in 0.21: Enter the body heat in W/kg.
   • 1.0 and above: Select the mode:
     • Dissipation Rate - enter the dissipation rate in W/kg .
     • Total Power - enter the total power in W.

Properties

• DataEnable Amplitude - introduced in 1.1: Enables the use of CalculiX's amplitude for the time variation of the body heat source load. At a given time, magnitude of the load is multiplied by the amplitude value corresponding to that time. Linear interpolation is used between the specified values. Constant values are used outside of the specified range.
• DataAmplitude Values - introduced in 1.1: Amplitude table in the following format:

time_1, amplitude_value_1
…

Default is linear increase from 0% at t=0 to 100% at t=1:

0, 0
1, 1

Limitations

• 0.20 and below: The body heat source is applied to the whole model, meaning all bodies of the setup. It is not possible to select an individual body.
• 0.21 and below: This feature only works with the Elmer solver.

Notes

• For more information see this forum thread and following posts. This thread may also be useful.
• Elmer examples can also be found in Elmer GUI Tutorials.
• 1.0 and above: This feature uses the *DFLUX card in CalculiX.
• 1.0 and above: Since CalculiX expects body heat flux input in W/mm^3 while for Elmer it's W/kg, the conversion of the specified value (in W or W/kg) is done internally for each solver, using the volume of the selected solid and the density of the material assigned to it, if needed.