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-   -   Heat transfer between fluid-solid-fluid (http://www.cfd-online.com/Forums/fluent/110837-heat-transfer-between-fluid-solid-fluid.html)

wista59 December 22, 2012 04:28

Heat transfer between fluid-solid-fluid
 
I am new user and am trying on heat transfer in Fluent .I have three domain (fluid-solid-fluid).I want to make Conjugate heat transfer here . I cant see a -shadow boundary condition of type wall for each interface wall .And I dont open coupled in thermal conditions.I am adding my system project pictures and files.

http://img690.imageshack.us/img690/2...nletoutlet.png
http://img19.imageshack.us/img19/423...nletoutlet.png
http://img850.imageshack.us/img850/9...weensolida.png
http://img694.imageshack.us/img694/4...eenfluidan.png
http://img831.imageshack.us/img831/6...conditions.png

Now , What I must do ?

For system drawing file download : https://hotfile.com/dl/185675827/a61...nsfer.rar.html


Best Regards...

macfly December 22, 2012 14:15

There should be no interface in your model.

Inner pipe surface BC should be set to wall.

Outer pipe surface BC should be set to wall as well.

LuckyTran December 23, 2012 01:08

Quote:

Originally Posted by macfly (Post 398688)
There should be no interface in your model.

Inner pipe surface BC should be set to wall.

Outer pipe surface BC should be set to wall as well.

There should be interfaces. There should also be shadow walls.

Though I'm also not sure why the shadow walls are not appearing.

Edit
I managed to open the files. The mesh imported by Fluent is already incorrect. So the problem is in the mesh.

wista59 December 23, 2012 03:42

Quote:

Originally Posted by LuckyTran (Post 398737)
There should be interfaces. There should also be shadow walls.

Though I'm also not sure why the shadow walls are not appearing.

Edit
I managed to open the files. The mesh imported by Fluent is already incorrect. So the problem is in the mesh.

How can I fix it ? What I must do ?

macfly December 23, 2012 08:56

2 Attachment(s)
Quote:

Originally Posted by LuckyTran (Post 398737)
There should be interfaces.

I did it without any interface. Look at the attached model with simpler mesh (I had some difficulties with the cylinder mesh...). It looks to me as if fluid dynamics and heat transfer are doing their job, the hot air in small pipe is cooled by the surrounding air. Boundary conditions for inner_pipe and outer_pipe are automatically set to 'coupled'.

Here are the files: http://dl.dropbox.com/u/64952262/z.zip

LuckyTran December 23, 2012 14:01

Quote:

Originally Posted by macfly (Post 398776)
I did it without any interface. Look at the attached model with simpler mesh (I had some difficulties with the cylinder mesh...). It looks to me as if fluid dynamics and heat transfer are doing their job, the hot air in small pipe is cooled by the surrounding air. Boundary conditions for inner_pipe and outer_pipe are automatically set to 'coupled'.

Here are the files: http://dl.dropbox.com/u/64952262/z.zip

I also took a look at your's. You have the wall with corresponding shadow wall that forms the two-sided wall or interface between the two zones. The two-sided wall is a mesh interface that transmits information from one mesh zone to another, otherwise there is no ability for the two zones to interact.

But wista is missing the wall and shadow-wall pair forming the two-sided wall / interface and that is why it is not working. The two-sided wall is built by the mesher and must be present when it is imported into Fluent.

macfly December 23, 2012 14:32

Yes, in ICEM CFD I created the blocking parts 'PIPE', 'AIR' and 'HOT_AIR', then the 3 mesh volumes are created when the Pre-Mesh in converted to unstruct mesh. Wista, check/uncheck everythig under 'Parts' in ICEM CFD and you will understand the mesh generation process.


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