CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > ANSYS Meshing & Geometry

[ICEM] Blocking and OGrid

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree5Likes
  • 5 Post By energy382

Reply
 
LinkBack Thread Tools Display Modes
Old   March 17, 2011, 08:27
Default Blocking and OGrid
  #1
New Member
 
Saikiran
Join Date: Sep 2010
Posts: 15
Rep Power: 6
Saikiran is on a distinguished road
Hello everyone.....I have to do an analysis for combustion modeling of butane brazing torch. I have the model for meshing but it looks quite difficult for me to start with blocking.Can someone give idea where to start with??

The funnel like structure at one end is modeled to capture the flame and circular faces of the two cylinders intersecting orthogonally are inlets for air.
Images of geometry are attached.
Thank you........
Attached Images
File Type: jpg geom1.jpg (17.2 KB, 84 views)
File Type: png geom2.PNG (28.2 KB, 60 views)
File Type: png geom3.PNG (74.4 KB, 59 views)
Attached Files
File Type: zip Geometry.zip (29.5 KB, 22 views)

Last edited by Saikiran; March 18, 2011 at 05:21.
Saikiran is offline   Reply With Quote

Old   March 18, 2011, 06:13
Default
  #2
Senior Member
 
AB
Join Date: Sep 2009
Location: France
Posts: 323
Rep Power: 12
BrolY will become famous soon enough
First of all, you should create one o-grid for your inner tube. Then split the O-grid everytime you have a change in the direction of the tube, and associate your edges AND points on the curves. It's important to "fix" your O -grid to avoid problems when you add others o-grids inside the 1st o-grid.
I guess your issue is located at the air inlets ? Create 2 splits to there, and use the extrude face options to capture the air inlets.
Also, another issue is located on pictures 2 : you may have have to creates 2 or 3 inner o-grids because to capture the geometry.

Try that by yourselves, and come back with a try to see what it looks like I can help you if you need.

Last edited by BrolY; March 18, 2011 at 06:48.
BrolY is offline   Reply With Quote

Old   March 19, 2011, 09:40
Default
  #3
New Member
 
Saikiran
Join Date: Sep 2010
Posts: 15
Rep Power: 6
Saikiran is on a distinguished road
Thanx for your instructions BroIY. I have followed your instructions.I have two issues:
1. The mesh near the surface of the inner tube looks fine but inside the cross it's messed up.
2. And the two intersecting cylinders. How to tacklet that one??
Pics of the same are attached
Thank you.
Attached Images
File Type: jpg mesh1.jpg (29.4 KB, 57 views)
File Type: jpg mesh2.jpg (99.6 KB, 69 views)
File Type: png mesh3.PNG (91.1 KB, 72 views)
Saikiran is offline   Reply With Quote

Old   March 21, 2011, 10:55
Default
  #4
Senior Member
 
AB
Join Date: Sep 2009
Location: France
Posts: 323
Rep Power: 12
BrolY will become famous soon enough
I attached the files of my project: .tin and .blk
I changed a few your geometry by adding new points and curves which help to fix the blocking. Here are the steps to create this mesh :
1) create an O-grid and cut it every time the section of the tube changes.
2) remove the blocks of the grid (but keep the inner one) which are located between the butane_inlet and right after the air_inlet (when the section of the tube drops)
3) associate all your points and curves
4) cut your block twice, before and after the air_inlet. Then extrude the face of the blocks (blocking -> create block -> extrude face with the option extrude along curve) to the air-inlet. Associate.
5) Create an o-grid between the butane_inlet and right after the air-inlet (when the section of the drops) and select the face of the butane_inlet and air_inlet for the ogrid
6) about the cross with the small tude inside, just cut your blocks in this area twice in the horizontale direction, and twice in the verticale direction. Associate, and delete the blocks which are not in the fluid

It should work well
I recommand you to try that by yourself, and just use my project as an example. Post some pictures if you are jamed !
Have fun
Attached Files
File Type: zip TORCH.zip (51.7 KB, 20 views)

Last edited by BrolY; March 21, 2011 at 11:34.
BrolY is offline   Reply With Quote

Old   March 22, 2011, 05:16
Default
  #5
New Member
 
Saikiran
Join Date: Sep 2010
Posts: 15
Rep Power: 6
Saikiran is on a distinguished road
Thank you BroIY. I finished it.
Saikiran is offline   Reply With Quote

Old   April 3, 2011, 11:58
Default
  #6
New Member
 
Saikiran
Join Date: Sep 2010
Posts: 15
Rep Power: 6
Saikiran is on a distinguished road
HELLO BroIY...your tips were helpful but i found some bad elements near the corners(on the cross) and i'm unable to initialize OGrid by selecting blocks and faces(ICEM gives an error). The picture is attached with the post.
Attached Images
File Type: jpg mesh.jpg (90.6 KB, 69 views)
Saikiran is offline   Reply With Quote

Old   April 4, 2011, 03:40
Default
  #7
Senior Member
 
AB
Join Date: Sep 2009
Location: France
Posts: 323
Rep Power: 12
BrolY will become famous soon enough
Once you created the two first O-grid,associate curves with edges (that's why I added some curves in your model, so you can associate your edges). Then, split your blocks around the cross (and only those blocks, do not propagate your splits) before doing the last O-grid.
Associate the curves (and points) you have splitted with the edges. Thanks to the splitting you've done for the cross, you can associate the 4 inner edges to the small curves of your small inner tube. Delete the blocks that you don't need and, at the end, you can do the last O-grid inside the small tube of the cross.
BrolY is offline   Reply With Quote

Old   April 4, 2011, 06:29
Default
  #8
New Member
 
Saikiran
Join Date: Sep 2010
Posts: 15
Rep Power: 6
Saikiran is on a distinguished road
Hey BroIY...I'm sorry...should have written the other way. My intention was to improve the mesh at the corners for which i have tried to use OGrid and it wasn't working. The model which u have shared with me also has some elements with high skewness factor(If i increase the number of nodes for an edge). I'm not pointing out anything.Just wanted to know.

Can give some general guidelines for improving the mesh quality??
Attached Images
File Type: jpg mesh.jpg (88.6 KB, 68 views)
Saikiran is offline   Reply With Quote

Old   October 2, 2012, 08:11
Default
  #9
New Member
 
nitin bansal
Join Date: Jun 2012
Location: INDIA
Posts: 27
Rep Power: 5
nitinbansal184 is on a distinguished road
Try Edge alignment,
Or try creating new Ogrid
Or try increasing number of nodes on edges with low quality mesh
nitinbansal184 is offline   Reply With Quote

Old   October 2, 2012, 09:13
Default
  #10
Senior Member
 
Christoph
Join Date: May 2011
Location: Germany
Posts: 182
Rep Power: 9
energy382 is on a distinguished road
this thread is 1,5 years old.

don't think, he's still busy with that project
Far, BrolY, stuart23 and 2 others like this.
energy382 is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
[ICEM] Blocking strategy around a sphere Mudblood ANSYS Meshing & Geometry 8 April 9, 2011 10:30
y+ Value & Aspect Ratio {Wind Tunnel Model} FabioT ANSYS Meshing & Geometry 18 October 5, 2010 15:00
[ICEM] Blocking strategy BrolY ANSYS Meshing & Geometry 0 July 22, 2010 04:46
ICEM Ogrid Brian_P ANSYS Meshing & Geometry 6 May 14, 2010 15:46
Blocking problem with ICEMCFD Charbonnier CFX 1 November 30, 2006 14:41


All times are GMT -4. The time now is 15:36.