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-   -   Pure conduction with chtMultiRegionSimpleFoam (https://www.cfd-online.com/Forums/openfoam/221080-pure-conduction-chtmultiregionsimplefoam.html)

Bourne OpenFoam October 3, 2019 09:52

Pure conduction with chtMultiRegionSimpleFoam
 
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Dear OpenFoamers,

I have a question for which I have not yet been able to find and answser.

Context:
I would like to simulate pure conduction throught 2 solids. For training purposes I have set the same thermal properties for both materials.

Unfortunatly I obtain an error in the results at the boundary layer between the two materials. I was expecting a linear temperature gradient, however I obtain a vertical drop in the temperature at the boundary between the 2 materials --> See picture.



Does anyone have a idea how to overcome this error? I believe it must have something to do with the boundary conditions.

My boundary condition for the interfaces are as follows:

"BigSolid_to_.*"
{
type compressible::turbulentTemperatureCoupledBaffleMix ed;
Tnbr T;
kappaMethod solidThermo;
kappaName none;
value uniform 300;
}

Many Thanks,

George

carye October 4, 2019 05:14

I think this is not an error of OF, but related to the post-processing.

to my knowledge, the plot over line filter in paraview is point based, so it will interpolate the values from the cell data to plot.
I think the jump comes from the interpolation.

you can set the resolution of the line in paraview to the size of the mesh direction, in your case, the x direction.
And read in not only the internalmesh but also the interface between the two regions, such as the interface of ..._to_...
then you should get a smooth plot.

I don't know whether paraview can plot the cell data or not ( I did not find the approach... ),
but you can also apply the cell centers filter to the domain and export the cell centers and data, use excel to process the data.

hope this helps you.
and please figure out if I was wrong.:)

Bourne OpenFoam October 29, 2019 04:10

Thanks for your reply, I took me a while but I found the solution.

I needed to set the inner wall as type calculated and then it worked :)

Hvae a good day!

andrewlindsay November 23, 2019 02:59

George,
I'm trying to do a similar thing too, are you able to share your case fie with me to use as a starting point on my journey?
I'm trying to solve the following axisymmetric problem using openfoam, firstly just as a pure conduction problem. Initially I want to solve a steady state version, and then look at transient behaviour.
Then if I get that to work, I may try to turn it into a cfd problem also.
https://login.filesanywhere.com/FS/M...8f5995a17aa499

photon_ed November 24, 2019 13:04

hey, can you tell me how you set up the linear temp gradient on the surface?
thanks


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