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-   -   heat flux on boussinesq (http://www.cfd-online.com/Forums/openfoam-solving/95254-heat-flux-boussinesq.html)

Andrev December 11, 2011 12:18

heat flux on boussinesq
 
Dear Foam's,

Im trying to set heat flux as a boundary condition of my buoyantboussinesqSimpleFoam case. But my solution is too dependent of the mesh resolution, as I refine my mesh the final temperature of the fluid descreases each time more.

Qflux = k*(gradT)
gradT = qflux/k ; k=0,17 , Qflux = 10000

so Im setting in the T file :

fixedWalls
{
type fixedGradient;
gradient uniform 58823;
}

Can anyone tell me what am I doing wrong ?

Thanks for the attention.

Andrev December 11, 2011 12:19

(Im considering K constant...)

romant December 12, 2011 02:27

does the temperature become less than the temperature that you calculate with the a simple heat balance?

what kind of turbulence modeling do you use?

Andrev December 12, 2011 06:05

Yes, it become less then that i calculated with simple heat balance as I refine mesh.

Its a laminar flow.

romant December 12, 2011 06:11

Quote:

Originally Posted by Andrev (Post 335525)
Yes, it become less then that i calculated with simple heat balance as I refine mesh.

Its a laminar flow.

what kind of geometry are we talking about, what is your yPlus of your first cell and what kind of fluid do u treat (Pr = 1, Pr > 1 or Pr < 1)

Andrev December 12, 2011 06:23

Its a simple rectangular channel section flow with constant heatflux on the fixed walls (4 walls), ethanol is the fluid (Pr ~ 16.5).


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