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-   -   [ICEM] Elliptical Geometry connector inserted in a pipe (http://www.cfd-online.com/Forums/ansys-meshing/108581-elliptical-geometry-connector-inserted-pipe.html)

alimrad110 October 26, 2012 17:12

Elliptical Geometry connector inserted in a pipe
 
3 Attachment(s)
Hi All,

I am trying to mesh an elliptical entity which connects two pipes together for a confined flow turbulence study. It is protruding from one pipe and inserted into another. The problem is that ICEM somehow doesn't recognise the insertion! as shown in figure 1. is this a face association problem?

Another problem is that on the narrow surface near the elliptical and pipe joints I get low quality mesh as shown in figure 2! I tried merging the ellipse on to the semi circle but that made everything worse as the mesh was originating from that point!

my blocking approach was starting from the ellipse, creating an oring to represent the ellipse and then extruding the blocks to the inlet and outlet.

Does anyone know how to fix these problems?

I know the blocking needs a lot of improvements but I can't go much further without fixing these two main problems.

The files are also attached!

nitinbansal184 October 29, 2012 01:57

1 Attachment(s)
Quote:

Originally Posted by alimrad110 (Post 388767)
Hi All,

I am trying to mesh an elliptical entity which connects two pipes together for a confined flow turbulence study. It is protruding from one pipe and inserted into another. The problem is that ICEM somehow doesn't recognise the insertion! as shown in figure 1. is this a face association problem?

Another problem is that on the narrow surface near the elliptical and pipe joints I get low quality mesh as shown in figure 2! I tried merging the ellipse on to the semi circle but that made everything worse as the mesh was originating from that point!

my blocking approach was starting from the ellipse, creating an oring to represent the ellipse and then extruding the blocks to the inlet and outlet.

Does anyone know how to fix these problems?

I know the blocking needs a lot of improvements but I can't go much further without fixing these two main problems.

The files are also attached!


Done in a single try..Reached minimum orthogonality 0.6
But mesh size around 2.7M.

Far October 29, 2012 02:37

All parts are included in blocking?

energy382 October 29, 2012 06:26

you've disregarded the most difficult part of geometry as far said in his previous post :D:D


Quote:

Originally Posted by nitinbansal184 (Post 389011)
Done in a single try..Reached minimum orthogonality 0.6
But mesh size around 2.7M.


alimrad110 October 29, 2012 16:41

Dear Alll,

Thanks for your effort!

Nitinbansa: As the others have expressed your blocking approach does not include the most important features of the geometry. The elliptical entry, the insertion and the chamfer of the ellipse.

I wish PSYMN took a look at this. I am getting the feeling that there could be a small glitch with ICEM in this case. because as far as I know the block has to be projecting the mesh onto the nearest surface and in the case of the insertion it is totaly ignoring it :confused: . May be I'm wrong about how ICEM works!!!

I really appreciate any effort to help me with this geometry as most of my efforts are failing!

Thank you!

diamondx October 29, 2012 18:18

@ali what did you use to make the geometry ?
is the fluid domain extracted ?? meshing can be easy if fluid domain is extracted ...
Can you share your geometry , if so can you export it in step ?

energy382 October 30, 2012 04:41

Quote:

Originally Posted by diamondx (Post 389196)
@ali what did you use to make the geometry ?
is the fluid domain extracted ?? meshing can be easy if fluid domain is extracted ...
Can you share your geometry , if so can you export it in step ?

hey ali, I don't get your point. Why is it easier to extract a negative form (in fact you're using icem hexa)!? I've never done it before and I don't understand in which way it distinguishs from "normal" approach, as blocking should be the same.

diamondx October 30, 2012 08:27

if you dont extract the fuid domain, you end up with trying to block unnecessary parts...

energy382 October 30, 2012 10:21

Quote:

Originally Posted by diamondx (Post 389272)
if you dont extract the fuid domain, you end up with trying to block unnecessary parts...

If you've a very complex geometry with many geometry features, you can extract fluid volume (altough I prefer to build topology and delete unnecessary parts). But in this geometry, you don't need that. It will definitely not simplify the blocking.

diamondx October 30, 2012 12:24

I'm reffering to places like in the red rectangle, from my understanding, fluid is not there...

https://dl.dropbox.com/u/35161486/elleptical.png

Far October 30, 2012 12:33

You mean the most difficult part ? alimrad110 should tell us which region is included in fluid domain?:(

diamondx October 30, 2012 15:52

having some free time, i opened up the geometry in designmodeler, i couldn't understand which path fluid is gonna take... special where the arrow points.

https://dl.dropbox.com/u/35161486/elleptical2.png

alimrad110 December 6, 2012 20:12

Hi All,

Sorry I have been away for a while and thank you for your efforts !!! Where you showed the arrow is sealed or if not sealed it is negligible for the sake of argument here, so the flow only goes through the elliptical opening !!!

I actually solved this case by extracting the fluid domain and re approximating the elliptical shape where it attaches the circular curve so that I end up with angles higher than 9 degrees !!!! Other method was to use a hybrid mesh and fill the low angles with tets which wasn't exactly what I wanted to do !!!

The most important thing was to associate surfaces with faces in the protrusion since the mesh does not recognise the protrusion. I will upload the mesh whenever get to my work computer!!!

I would appreciate your opinions on the approach !!!

Thank you very much everyone for your responses !!!


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