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-   -   How to model a fan/propeller (http://www.cfd-online.com/Forums/openfoam/84700-how-model-fan-propeller.html)

Aerospace February 7, 2011 05:03

How to model a fan/propeller
 
Hi everybody

I would like to simulate the tail rotor of an helicopter, and I would like try it without modelling the rotating blades (I am trying to avoid 3D model and MRF).

I am trying modelling a pressure jump between two walls pretty close, setting the same input/output velocity (as I use an incompressible solver, the mass flow rate should be the same too) and a total pressure jump between them. I am not sure about the final results.

Has anyone alredy tried it? I need some advices to continue my simulation or new ideas about how to model it.

Thank you.

nimasam February 7, 2011 06:00

fan type
 
1 Attachment(s)
Quote:

Originally Posted by Aerospace (Post 293918)
Hi everybody

I would like to simulate the tail rotor of an helicopter, and I would like try it without modelling the rotating blades (I am trying to avoid 3D model and MRF).

I am trying modelling a pressure jump between two walls pretty close, setting the same input/output velocity (as I use an incompressible solver, the mass flow rate should be the same too) and a total pressure jump between them. I am not sure about the final results.

Has anyone alredy tried it? I need some advices to continue my simulation or new ideas about how to model it.

Thank you.

search for "fan" in froum
look at attached file

Aerospace February 8, 2011 05:28

Quote:

Originally Posted by nimasam (Post 293939)
search for "fan" in froum
look at attached file

Hi nimasam, thank you for your reply.

I have not explied this, but I maybe have sawn all threads about this issue and I though any of them wans'n easy to apply to my case.

I have already tryed it, applying attached file structure. But in the attached file the geometry is quite simple, and you can identify handly the nodes which form fan faces. Well, in my case I'm using a mesh exported from Gambit, and I have already tryed somethin like that, but an internal face isn't recognised by OpenFOAM when you use "fluentMeshToFoam", and you lost the information of the face. So you have no internal face if you import a mesh from other program.

Have you got any solution or idea about how I can sovle it?

nimasam February 8, 2011 16:38

your solution is fan type boundary between to internal face! but now ur problem is some thing else :) , ur problem now is how to import mesh from gambit and still save the internal face and my answer is i dont know !!! so i suggest you too open new thread and ask ur question about mesh import and internal face there may be some one knows

Aerospace February 10, 2011 08:24

Quote:

Originally Posted by nimasam (Post 294279)
your solution is fan type boundary between to internal face! but now ur problem is some thing else :) , ur problem now is how to import mesh from gambit and still save the internal face and my answer is i dont know !!! so i suggest you too open new thread and ask ur question about mesh import and internal face there may be some one knows

Ok, thank you for your information.

It is probably what I will put a new thread por that question.

olivierG February 10, 2011 08:55

Hello,
You should use fluentMeshToFoam wiht the -writeSets option to get the internal wall.
Then you need to split the mesh.
An easy way is to use pyFoamAddEmptyBoundary (add fan and fan-shadow), pyFoamChangeBoundaryType (set to cyclic) and then use splitMesh

olivier


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