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. 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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#* Press the {{Button|[[Image:FEM_ConstraintHeatflux.svg|16px]] [[FEM_ConstraintHeatflux|Heat flux load]]}} button.
#* Press the {{Button|[[Image:FEM_ConstraintHeatflux.svg|16px]] [[FEM_ConstraintHeatflux|Heat flux load]]}} button.
#* Select the {{MenuCommand|Model → Thermal boundary conditions and loads → [[Image:FEM_ConstraintHeatflux.svg|16px]] Heat flux load}} option from the menu.
#* Select the {{MenuCommand|Model → Thermal boundary conditions and loads → [[Image:FEM_ConstraintHeatflux.svg|16px]] Heat flux load}} option from the menu.
# In the [[3D_view|3D view]] select the face(s) the constraint should be applied to.
# Click the {{Button|Add}} button. In the [[3D_view|3D view]] select the face(s) on which the heat flux load should be applied. Optionally, click the {{Button|Remove}} button to remove the selected faces from the selection list.
# Choose the heat flux type and specify its parameters:
# Enter the desired surface temperature, heat transfer coefficient and environment 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''
===Option===
#* ''Surface heat flux'' - general heat flux, enter the ''Surface heat flux'' in Watts per surface area (W/m^2)

By default, this feature defines a convective heat flux. By using the option '''Surface heat flux''', one can specify a heat flux value in Watts per surface area (W/m^2).


==Notes== <!--T:5-->
==Notes== <!--T:5-->


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* The heat flux load uses the *FILM card in CalculiX. It is explained at http://web.mit.edu/calculix_v2.7/CalculiX/ccx_2.7/doc/ccx/node203.html
* The heat flux load uses the following CalculiX cards depending on the selected mode:
* The surface heat flux option uses the *DFLUX card in CalculiX: http://web.mit.edu/calculix_v2.7/CalculiX/ccx_2.7/doc/ccx/node188.html
** [http://web.mit.edu/calculix_v2.7/CalculiX/ccx_2.7/doc/ccx/node203.html *FILM] for the ''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''
** [http://web.mit.edu/calculix_v2.7/CalculiX/ccx_2.7/doc/ccx/node188.html *DFLUX] for the ''Surface heat flux''



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Latest revision as of 16:45, 18 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