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

Hollow cube creation with the top end open in design modeller

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

Reply
 
LinkBack Thread Tools Display Modes
Old   May 10, 2009, 20:31
Smile Hollow cube creation with the top end open in design modeller
  #1
New Member
 
ram
Join Date: May 2009
Posts: 6
Rep Power: 8
ram881973 is on a distinguished road
Hello! iam new to ansys design modeller.may pl anyone suggest how to create a hollow cube with top end open.while creating a plane & extruding it is giving solid model.pl help.

ram
ram881973 is offline   Reply With Quote

Old   May 11, 2009, 09:41
Default What are you trying to get?
  #2
Senior Member
 
PSYMN's Avatar
 
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,662
Blog Entries: 1
Rep Power: 36
PSYMN has a spectacular aura aboutPSYMN has a spectacular aura about
Do you want a surface model (5 surfaces) or a thin solid box with an open top?
PSYMN is offline   Reply With Quote

Old   May 11, 2009, 23:38
Default
  #3
New Member
 
ram
Join Date: May 2009
Posts: 6
Rep Power: 8
ram881973 is on a distinguished road
It is thin soild walls(hollow) with top end open.Actually iam modelling a furnace.
pl help me out.

ram
ram881973 is offline   Reply With Quote

Old   May 12, 2009, 14:58
Default Again: what are you trying to get?
  #4
Member
 
Jules Bell
Join Date: May 2009
Posts: 31
Rep Power: 8
Jules is on a distinguished road
Hey ram, to me it's also not quite clear what you are trying to get. Do you want to model the walls themselves (that is the solid walls that PSYMM ist talking about, IMHO), just draw two rectangles/squares on one plane, one inside the other, extrude the outer one first and then extrude the inner and subtract.
If you want to model (mesh) the inside of the box (furnace), a simple extrude from the top face should suffice, because you always have to model the fluid itself, not the structure around it.
Maybe a quick sketch of yours (e.g. in MS paint, or scan a pencil sketch from paper) helps to clarify.

Cheers,

Jules
Jules is offline   Reply With Quote

Old   May 13, 2009, 10:27
Default Baffle Surface?
  #5
Senior Member
 
PSYMN's Avatar
 
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,662
Blog Entries: 1
Rep Power: 36
PSYMN has a spectacular aura aboutPSYMN has a spectacular aura about
If you want a zero thickness structural model, you could create the thin solid box and midsurface it. I think you can also create the 5 surfaces as surfaces, but I have less experience with that.

I am guessing that you oversimplified what you really want to do and that is what has confused us... You probably want a zero thickness baffle? like a furnace made of sheet metal in a larger farfield flow? You want to model the flow around the sheet metal (both sides), but don’t want to model the thickness? At this point DM does not support baffles, but it is a high priority enhancement request for the next release.

In the mean time, you could build your box as a volumetric flow region cut out of your far field. Mark 5 of the sides as walls and the 6th as open. The wall boundary conditions would act as the sheet metal and the opening(s) would allow flow between the volumes.

Another option would be to use a tool like ANSYS ICEM CFD or Fluent GAMBIT that allows for the straight up use of baffles.
PSYMN is offline   Reply With Quote

Old   May 14, 2009, 00:20
Default
  #6
New Member
 
ram
Join Date: May 2009
Posts: 6
Rep Power: 8
ram881973 is on a distinguished road
Dear Mr.Psymn & Mr. Jules

ThankQ very much for ur interest in clearing my doubt.Iam very sorry for not presenting my doubt clearly.I have attached the 2d and(front view) and 3d geometry for reference.
my plan of work is as follows
1) creating the model of black liquor recovery boiler(furnace).
2) creating the air injection ports and black liquor drop injection nozzles
3)simulating the physical and chemical process(combustion and reduction process)in side the furnace
Actually iam creating the furnace geometry as a boundary of chemical and physical process and for attaching air/liquor ports .
ypu are requested to help me out.
Attached Files
File Type: zip Presentation1.zip (76.2 KB, 17 views)
ram881973 is offline   Reply With Quote

Old   May 14, 2009, 14:53
Default questions about doubts...
  #7
Senior Member
 
PSYMN's Avatar
 
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,662
Blog Entries: 1
Rep Power: 36
PSYMN has a spectacular aura aboutPSYMN has a spectacular aura about
I don’t have time to look into this properly right now… Just a few minutes while a job is running. Maybe Jules or someone else will have a chance.

Don’t get me wrong, I have the utmost respect for engineers who learn English as a second language while still in their home country... But I think there is some terrible English teacher running around the world telling everyone to use the word “doubts” as equivalent to “questions”.

I have worked around the world and seen this as very common on three continents. I have also seen American presenters get very flustered when dozens of people from the audience (at home or abroad) all stand up to express “doubts” regarding their work… Once after my presentation, my manager expressed concern that the audience didn’t believe me, I had to explain my theory about the well traveled, but misguided English teacher.


In English, “doubts” has a very negative connotation. It means you think the other person is either mistaken or outright lying, either way you don’t believe them.


Use the word “questions” instead; unless you really didn’t believe us...
PSYMN is offline   Reply With Quote

Old   May 14, 2009, 22:31
Default
  #8
New Member
 
ram
Join Date: May 2009
Posts: 6
Rep Power: 8
ram881973 is on a distinguished road
Quote:
Originally Posted by PSYMN View Post
I don’t have time to look into this properly right now… Just a few minutes while a job is running. Maybe Jules or someone else will have a chance.

Don’t get me wrong, I have the utmost respect for engineers who learn English as a second language while still in their home country... But I think there is some terrible English teacher running around the world telling everyone to use the word “doubts” as equivalent to “questions”.

I have worked around the world and seen this as very common on three continents. I have also seen American presenters get very flustered when dozens of people from the audience (at home or abroad) all stand up to express “doubts” regarding their work… Once after my presentation, my manager expressed concern that the audience didn’t believe me, I had to explain my theory about the well traveled, but misguided English teacher.


In English, “doubts” has a very negative connotation. It means you think the other person is either mistaken or outright lying, either way you don’t believe them.


Use the word “questions” instead; unless you really didn’t believe us...
Dear Mr Psymn
Sorry........ Iam very sorry for using the word "doubt" .As told by u iam not proficient in english and really you have helped me a lot by telling it's meaning and how it hurt's someone inadvertently . But i request you ,if you have time ,pl help me out in solving my modelling problem.Even if you could not find the time,Still i will have great respect in you as you are the first person to respond to my question and shown intrest towards solving my problem.

ThankQ very much
ram
ram881973 is offline   Reply With Quote

Old   May 15, 2009, 19:14
Default
  #9
Member
 
Jules Bell
Join Date: May 2009
Posts: 31
Rep Power: 8
Jules is on a distinguished road
ram, from what I understand you have to model the solid region INSIDE the furnace, because this is where the fluids that you want to simulate, are located.
I'm not too familiar with the design modeller, I did some basic CFX tutorials (the one with flow in a static mixer) using design modeller, but this was years ago. As far as I remember it works like pretty much any solid model CAD tool.
You should make a sketch of the sideview (in design modeller) and extrude it to get the solid model. Then you can make other sketches (circles) and extrude them for the injection ports and nozzles. With any solid you create you also create the bounding surfaces, so you will have these available as boundaries later.
You could also create the geometry in another CAD program and import it.

Besides that, you might want to work through the basic cfx tutorials. After all, it seems to me like the static mixer tutorial is somewhat similar to your problem.

Best wishes,

Jules
Jules is offline   Reply With Quote

Old   May 17, 2009, 17:09
Default Agreed
  #10
Senior Member
 
PSYMN's Avatar
 
Simon Pereira
Join Date: Mar 2009
Location: Ann Arbor, MI
Posts: 2,662
Blog Entries: 1
Rep Power: 36
PSYMN has a spectacular aura aboutPSYMN has a spectacular aura about
I agree, if you just need to model the inside, Jules is right. Actually, I recomend working thru some tutorials anyway. You may just want to start with the basic shape and then imprint the surface features you want on it... You can use the sketch tool in DM.

If you want the thin sheet metal in a larger farfield, look at my earlier post.

Good luck.

Simon
PSYMN 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
Simulation of a single bubble with a VOF-method Suzzn CFX 18 October 2, 2009 04:18
No results for solid domain Gary Holland CFX 10 March 13, 2009 04:30
Concentric tube heat exchanger (Air-Water) Young CFX 5 October 6, 2008 23:17
about compresive phase James CFX 10 September 12, 2006 03:16
Two-Phase Buoyant Flow Issue Miguel Baritto CFX 4 August 31, 2006 12:02


All times are GMT -4. The time now is 14:59.