FEM ConstraintHeatflux: Difference between revisions

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Defines a convective heat flux load on a surface at a temperature ''T'' with a film coefficient ''h'' and with the environment (sink) temperature ''T<sub>0</sub>''. The convective heat flux ''q'' will satisfy: '''''q = h(T -T<sub>0</sub>)'''''. Optionally, can also define a regular surface heat flux load.
By default, defines a convective heat flux load on a surface at a temperature <math>T</math> with a film coefficient <math>h</math> and with the environment (sink/ambient) temperature <math>T_{0}</math>. The convective heat flux <math>q</math> will satisfy: <math>q=h(T-T_{0})</math>. Optionally, can also define a regular surface heat flux load.


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{{Version|1.0}}: Can be also used to define a radiation heat flux on a surface.
{{Version|1.0}}: Can be also used to define a radiation heat flux on a surface. It satisfies: <math>q=\epsilon \sigma(T^{4}-T_{0}^{4})</math> where <math>\epsilon</math> is the surface emissivity and <math>\sigma</math> is the Stefan-Boltzmann constant.


==Usage== <!--T:3-->
==Usage== <!--T:3-->
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#* ''Surface Convection'' (default) - convective heat flux, enter the desired ''Film coefficient'' and ''Ambient temperature''
#* ''Surface Convection'' (default) - convective heat flux, enter the desired ''Film coefficient'' and ''Ambient temperature''
#* {{Version|1.0}}: ''Surface Radiation'' - radiation heat flux, enter the surface ''Emissivity'' and ''Ambient temperature''
#* {{Version|1.0}}: ''Surface Radiation'' - radiation heat flux, enter the surface ''Emissivity'' and ''Ambient temperature''
#* ''Surface heat flux'' - enter the ''Surface heat flux'' in Watts per surface area (W/m^2)
#* ''Surface heat flux'' - general heat flux, enter the ''Surface heat flux'' in Watts per surface area (W/m^2)


==Notes== <!--T:5-->
==Notes== <!--T:5-->
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* The heat flux load uses the following CalculiX cards depending on the selected mode:
* The heat flux load uses the following CalculiX cards depending on the selected mode:
** [http://web.mit.edu/calculix_v2.7/CalculiX/ccx_2.7/doc/ccx/node203.html *FILM] for the ''Surface Convection''
** [http://web.mit.edu/calculix_v2.7/CalculiX/ccx_2.7/doc/ccx/node203.html *FILM] for ''Surface Convection''
** {{Version|1.0}}: [http://web.mit.edu/calculix_v2.7/CalculiX/ccx_2.7/doc/ccx/node234.html *RADIATE] for the ''Surface Radiation''
** {{Version|1.0}}: [http://web.mit.edu/calculix_v2.7/CalculiX/ccx_2.7/doc/ccx/node234.html *RADIATE] for ''Surface Radiation''
** [http://web.mit.edu/calculix_v2.7/CalculiX/ccx_2.7/doc/ccx/node188.html *DFLUX] for the ''Surface heat flux''
** [http://web.mit.edu/calculix_v2.7/CalculiX/ccx_2.7/doc/ccx/node188.html *DFLUX] for ''Surface heat flux''





Latest revision as of 12:14, 22 May 2024

FEM ConstraintHeatflux

Menu location
Model → Thermal boundary conditions and loads → Heat flux load
Workbenches
FEM
Default shortcut
None
Introduced in version
-
See also
FEM tutorial

Description

By default, defines a convective heat flux load on a surface at a temperature with a film coefficient and with the environment (sink/ambient) temperature . The convective heat flux will satisfy: . Optionally, can also define a regular surface heat flux load.

introduced in version 1.0: Can be also used to define a radiation heat flux on a surface. It satisfies: where is the surface emissivity and is the Stefan-Boltzmann constant.

Usage

  1. There are several ways to invoke the command:
    • Press the Heat flux load button.
    • Select the Model → Thermal boundary conditions and loads → Heat flux load option from the menu.
  2. Click the Add button. In the 3D view select the face(s) on which the heat flux load should be applied. Optionally, click the Remove button to remove the selected faces from the selection list.
  3. Choose the heat flux type and specify its parameters:
    • Surface Convection (default) - convective heat flux, enter the desired Film coefficient and Ambient temperature
    • introduced in version 1.0: Surface Radiation - radiation heat flux, enter the surface Emissivity and Ambient temperature
    • Surface heat flux - general heat flux, enter the Surface heat flux in Watts per surface area (W/m^2)

Notes