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Boundary condition for conjugate thermal heat conduction

Hi all;

What kind of boundary condition is suitable for interface of two solid part jointed together (in the presence of conjugate conduction heat transfer )?
If the answer is mixed boundary, what kind of mixed boundary should I select in OF2.3.1?

Thx for any answer& help.:)

Quote:

Originally Posted by Asghari_M (Post 541147)

look in the tutorial examples heatTransfer/chtMultiRegionFoam/multiRegionHeater and heatTransfer/chtMultiRegionSimpleFoam/multiRegionHeater for without and with radiation

Dear Derekm,
Thanks!
I look in them. The codes are similar to following ones:

Code:

            "leftSolid_to_.*"

            {

                type            compressible::turbulentTemperatureCoupledBaffleMixed;

                Tnbr            T;

                kappa           solidThermo;

                kappaName       none;

                value           uniform 300;

            }

I have some questions in relation with the above code:
1-What is the difference between compressible::turbulentTemperatureCoupledBaffleMix ed and calculated?
2-What's the reason for use of turbulent and compressiblenomeclature in this boundary condition type? Specially, since there isn't any fluid region
in the my problem .
3-What is the deference in terms of thicknessLayer and kappaLayers between above and following code (used in the same changeDictionaryDict file)?

Code:

            leftSolid_to_heater

            {

                type            compressible::turbulentTemperatureCoupledBaffleMixed;

                Tnbr            T;

                kappa           solidThermo;

                kappaName       none;

                thicknessLayers (1e-3);

                kappaLayers     (5e-4);

                value           uniform 300;

            }

I would appreciated for any help for finding my answers.

Hi Asghari

I am also struggling with the boundary conditions for CHT cases.

From my experience I can answer a bit of your 1st question. The BC "compressible::turbulentTemperatureCoupledBaffleMix ed" is used primarily for coupling between a solid and a fluid region through interface. And the BC "calculated" is used when one does want to give the value directly rather derive it from other values using equations.

I hope this helps you. Please let me know if I am wrong somewhere.

Regards
Gautam

Quote:

Originally Posted by Asghari_M (Post 541220)

2-What's the reason for use of turbulent and compressiblenomeclature in this boundary condition type? Specially, since there isn't any fluid region
in the my problem .

3-What is the deference in terms of thicknessLayer and kappaLayers between above and following code (used in the same changeDictionaryDict file)?

Code:

            leftSolid_to_heater

            {

                type            compressible::turbulentTemperatureCoupledBaffleMixed;

                Tnbr            T;

                kappa           solidThermo;

                kappaName       none;

                thicknessLayers (1e-3);

                kappaLayers     (5e-4);

                value           uniform 300;

            }

I would appreciated for any help for finding my answers.

Hi Mehdi,

I am a newbie in OF, though it's been about two months that I am working on a multi-region conduction (so far) problem. I guess I improoved enough to be able to answer or at least give some insight to your questions.

2- Neither I have a fluid region yet (though I hope I will get to the point to add some), but if you use any different coupling condition as can be found in the forum regarding old OF version, an error message will pop up in log showing a list of possible entries. None of them will be suitable-er than that one indeed. I guess most people using OF are more interested in solid couplings with compressible turbulent fluid regions and so far there is no multiRegionLaplacian (or Conduction) solver...

3- The second code quoted has some addictional thermal contact resistance between two solids with properties defined by the two entries, thickness and conductivity of the resistance layer...

Hope it helped you out!

Quote:

Originally Posted by gomsy1987 (Post 541367)

Dear Gautam,
I think it is possible to use compressible::turbulentTemperatureCoupledBaffleMix ed for solid to solid interfaces.
My reason for this comment is this fact that in CHT tutorial and in changeDictionaryDict, I saw follow interface type:

Code:

            

leftSolid_to_heater  

           {  

  type            compressible::turbulentTemperatureCoupledBaffleMixed; 

  Tnbr            T;  

  kappa           solidThermo;   

  kappaName       none; 

  thicknessLayers (1e-3);            

  kappaLayers     (5e-4);            

  value           uniform 300;    

         }

Since both leftsolid and heater are solid, therefore I conclude that this boundary type can be used for pure solid to solid interfaces.
But this is something that I do not understand why compressible and turbulent has been used in nomenclature of this interface type (compressible::turbulentTemperatureCoupledBaffleMixed).

Hello Asghari

I completely agree with you. That is why I mentioned in my post "used primarily". I meant to say it has nothing much to do with the nomenclature.

Regards
Gautam

Dear Friends!

All of your replies were actually helpful.

Best wishes for you.
M.Asghari