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-   -   Conjugated heat transfer problem:chtmultiregionSimpleFoam (http://www.cfd-online.com/Forums/openfoam/122072-conjugated-heat-transfer-problem-chtmultiregionsimplefoam.html)

 Ank August 12, 2013 00:54

Conjugated heat transfer problem:chtmultiregionSimpleFoam

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Dear all,

I am trying to solve a conjugated heat transfer problem. There are four rows of tubes with external circular fins on it. The tubes are given a constant temperature and then the conduction through the fins has to be considered. The outside fluid is air at a constant temperature and velocity. I am able to run the tutorial given in the openfoam but I am finding it to apply to my case. Another problem is I am making the geometry in Gmsh, can anybody help me how do I setup the case with the mesh from Gmsh. I am attaching a snapshot of my problem. Kindly have a look at it.

 elvis August 12, 2013 04:51

Hi,

what about using Engrid (it is opensource software, free of charge) it creates OF meshes and the example is made for conjugate heat transfer with OPENFOAMŪ's chtMultiRegionSimpleFoam ?
https://github.com/enGits/engrid/wik...heat-exchanger

To create Geometries engrid prefers to get geomīs from blender

and you should also should be able to import your gmesh stuff

 Ank August 12, 2013 05:20

Hey

I am not familiar with Engrid but I have downloaded it and will try to understand how it works.

I can create different volumes with gmsh also, for example fin is the solid part in my case and each fin is circular in shape with 6 faces. I have four fins, so is it like I have to make solid 1, solid 2, solid 3, solid 4 and then I have to make solid1_top, solid1_bottom etc..? Please guide me if u have any idea about this. I have single fluid region which is air, so one volume for that would be enough.

 msarkar August 13, 2013 03:37

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Quote:
 Originally Posted by Ank (Post 445119) Hey Thanks for the quick reply. I am not familiar with Engrid but I have downloaded it and will try to understand how it works. I can create different volumes with gmsh also, for example fin is the solid part in my case and each fin is circular in shape with 6 faces. I have four fins, so is it like I have to make solid 1, solid 2, solid 3, solid 4 and then I have to make solid1_top, solid1_bottom etc..? Please guide me if u have any idea about this. I have single fluid region which is air, so one volume for that would be enough.
Hi Ankur,

You can continue using gmsh if you want. It is not very difficult to convert the gmsh mesh to Foam mesh. You define all the surfaces and volumes properly in your geo file and create mesh. You use gmshToFoam utility to convert your mesh to foam format. If you have single mesh file for fluid and solid, you can use topoSet and subsetMesh to create appropriate regions. If conditions are same for all your solid regions, you can define one solid volume including all solids. A sample bash script is attached here. This shows the process for two regions.

 elvis August 13, 2013 04:25

Hi,

Engrid has it own discussion here on CFD-Online
http://www.cfd-online.com/Forums/engrid/

Engrid has itīs pros and cons, there is interesting development to come like "handling polyhedral cells directly inside engrid" or engrid is one of the few mesher supporting SU2

Oliver Gloth the "spiritus rector" of engrid is also here http://www.cfd-online.com/Forums/members/ogloth.html

 Ank August 13, 2013 05:14

Hey Msarkar,

Thanks alot for the help. I know how to use Gmsh and to run its mesh in openFoam, the only problem is the conjugate type problem in which how to divide the regions etc..but you have told me useful things and I am going to work upon it and will get back to you.

 Ank August 13, 2013 05:16

Hey Elvis,

I am going to see the Engrid also, It will take sometime to understand this new software, if I find it easier than Gmsh then will try to solve my problem by Engrid. As msarkar has replied that it is possible to make the mesh in Gmsh also so I am going to use Gmsh for now. Thanks for the help..I will see if its easy to learn Engrid.

 Ank August 13, 2013 13:42

Hey Msarkar,

Do we have to give the bounding box info ourselves? because topoSetDict.fluid1 is supposed to be already present..as I have understood.

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