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radiative heat wall flux

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Old   March 15, 2017, 06:45
Default radiative heat wall flux
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nta
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Hello everyone,
I wanted test the buoyantSimpleRadiationFoam, and therefore I set a 2D Mesh 0.1x0.1

with:
  1. grayDiffusive boundaries left and right and wideBandSpecularRadiation on the top and bottom
  2. on the right side 1K and on the left side 0.01K
  3. using the fvDOM radiationModel with no emission and absorbtion of the fluid
viscosity is choosen high, so no velocity occure.
From theory the value of the radiative wall heat flux should be the value of the stefan boltzmann constant, 5.6*10**-8, but the value openFoam calculate is 3 times higher, 1.78*10**-7.
This factor of 3 is observed at different temperatures, so my question is:
Is this Qr calculated in the solver not the radiation wall heat flux, but a value proportional to it? Or is there some other mistake?
cheers
nta
Attached Files
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File Type: gz cavity.jou.tar.gz (677 Bytes, 1 views)
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Old   March 15, 2017, 08:14
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Uwe Pilz
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What is about your z coordinate? It should have a spread of 1, because all values are calculated in 3D.
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Old   March 15, 2017, 08:24
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The value is not depended of the length of the z coordinate. I simulated it wit a width of 0.1 and 1.
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