ElmerGUI Multi-body heat transfer problem

The graphical user interface of Elmer
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insainsa
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Joined: 26 Mar 2019, 14:49
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ElmerGUI Multi-body heat transfer problem

Post by insainsa » 26 Mar 2019, 15:10

Hello,
I am conducting a project where I have to simulate the flow of the coolant in a geothermal probe and its influence on the surroundings. I consider only a section of the probe as seen in the pictures.
maillage.png
maillage.png (120.33 KiB) Viewed 221 times
Arround is the ground, the circle is the bentonite, the 4 circles inside are the tubes (PEHD) and inside them is the fluid.
The mesh is 2D (x,y). I consider every element static, so I only used the heat equation and not Navier-Stokes.
I put a body force (-500) in the fluid circles to simulate the power taken from the probe. All the bodies are at 13.5 degrees Celsius at t=0. I chose .vtk for the output results and I view them with Paraview. Here is what I get :
simulation.png
simulation.png (17.86 KiB) Viewed 221 times
We can see that no conduction or convection operates in the system between the bodies. I tried to mimic the example of the Glacier and Bedrock from the Elmer Documentation but in vain.
Question :
How can I force the heat transfer between the different bodies ?
Here is my case :
case.sif
(4.13 KiB) Downloaded 12 times
Please help me, I've run out of ideas to solve this.

Thank you.

EDIT : my mesh was generated with GMSH and it seems to be conformal, but I'm not sure. How can you tell ?

mzenker
Posts: 1902
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: ElmerGUI Multi-body heat transfer problem

Post by mzenker » 26 Mar 2019, 18:11

insainsa wrote:
26 Mar 2019, 15:10
my mesh was generated with GMSH and it seems to be conformal, but I'm not sure. How can you tell ?
View it with gmsh, zoom to the interfaces, display nodes and node numbers and check that they are not duplicated.
The picture look very much like your mesh is not conformal.

HTH,
Matthias

insainsa
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Re: ElmerGUI Multi-body heat transfer problem

Post by insainsa » 26 Mar 2019, 19:17

Hi Matthias,
Indeed I have a lot of duplicate nodes. I work with the graphical user interface of Gmsh : is there a way to remove them via this interface, or do I have to learn how to use Gmsh with the script ?

Thanks !

kevinarden
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Re: ElmerGUI Multi-body heat transfer problem

Post by kevinarden » 26 Mar 2019, 22:30

To merge nodes, use the following command:

Geometry.Tolerance = 1e-3; // adjust value here for correct merge result
Coherence Mesh;

By default, the nodes in the surface with lower surface/volume number will survive. If you want the opposite, you can either assign different numbers to them or apply this change which reverses the order.

Salome, has a remove duplicate node command as well.

insainsa
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Re: ElmerGUI Multi-body heat transfer problem

Post by insainsa » 26 Mar 2019, 22:34

Thank you but I am not familiar with the use of commands at all. Should I write this in the geo file ? Should I write it in the terminal (Windows) ? Can I enter it using the graphical user interface ?

Thank you very much.

insainsa
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Re: ElmerGUI Multi-body heat transfer problem

Post by insainsa » 26 Mar 2019, 23:05

Thank you but I am not familiar with the use of commands at all. Should I write this in the geo file ? Should I write it in the terminal (Windows) ? Can I enter it using the graphical user interface ?

Thank you very much.

kevinarden
Posts: 155
Joined: 25 Jan 2019, 01:28
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Re: ElmerGUI Multi-body heat transfer problem

Post by kevinarden » 27 Mar 2019, 12:29

I could not find a way to do it in the graphical user interface. I would put it at the end of the geo file.

Kevin

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