CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > CFX

How to use values of a plane cutting the domain for inlet conditions?

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 27, 2012, 03:49
Default How to use values of a plane cutting the domain for inlet conditions?
  #1
New Member
 
Join Date: Mar 2012
Posts: 27
Rep Power: 14
StefanG is on a distinguished road
Dear all,

I have the case that I want to simulate a flow channel containing a combustion chamber in which I want to inject vaporized kerosene. The problem is that my computational ressources are quite limited. By now I have results for my flow channel without injecting anything. As I need a very fine mesh in the injection region (which leads to a big mesh), I want to cut my flow channel by a plane upstream the injection point and use these results from this plane as my inlet conditions for my case with injection and then just calculating this part.

By now I have no idea how I could manage this. Any help and suggestions are highly appreciated!

Best regards,
Stefan
StefanG is offline   Reply With Quote

Old   June 27, 2012, 08:39
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,665
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
Have a look at the profile boundary condition option.
ghorrocks is offline   Reply With Quote

Old   June 27, 2012, 10:05
Default
  #3
New Member
 
Join Date: Mar 2012
Posts: 27
Rep Power: 14
StefanG is on a distinguished road
Thanks for your hint, Glenn. This is exactly what I was looking for.

But now I have problems Importing it. I performed the following steps:

First I created a plane in ANSYS CFX Post. Then I exported the data on this plane to a BC Profile. Afterwards I started CFX Pre and wanted to Import it, but it crashes everytime.

I exported data for all variables except of that for heat flux.

Any idea what could be the reason?
StefanG is offline   Reply With Quote

Old   June 27, 2012, 10:22
Default
  #4
Member
 
Peter Galimutti
Join Date: May 2012
Posts: 37
Rep Power: 13
p.galimutti is on a distinguished road
in the cfd post go to file--> export--> velocity & other variables required at the plane.

you should be able to get a .csv file with physical co-ordinates and their corresponding variable values.

i don't remember importing, but i'll post the rest after i get accesss to CFX.

but if this is what you have done ignore it!
p.galimutti is offline   Reply With Quote

Old   June 27, 2012, 10:26
Default
  #5
New Member
 
Join Date: Mar 2012
Posts: 27
Rep Power: 14
StefanG is on a distinguished road
Dear Peter,

this is exactly what I did, but I want to export values for all variables. So I chose costum export and not total pressure or velocity option for export as with this options it is only possible to export a part of the variables.

But with this custom option CFX Pre crashes when I want to import my file.

When I choose total pressure option instead it works fine, but as I wrote I would like to have tha values for all variables.
StefanG is offline   Reply With Quote

Old   June 27, 2012, 10:39
Default
  #6
Member
 
Peter Galimutti
Join Date: May 2012
Posts: 37
Rep Power: 13
p.galimutti is on a distinguished road
you just need velocity or pressure and thermal bcs for initialization.

if it crashes it may be due to systems limited resources as you mentioned earlier.


Probably what you can do is give initial condition in 'Initial value specification' in the 'Solver Manager'. All you need to do is use the previous result file. however it may warn you that the initial mesh is not matching the new mesh, but it's alright, the values get interpolated.

HTH

Last edited by p.galimutti; June 27, 2012 at 13:00.
p.galimutti is offline   Reply With Quote

Old   June 28, 2012, 04:56
Default
  #7
New Member
 
Join Date: Mar 2012
Posts: 27
Rep Power: 14
StefanG is on a distinguished road
As Inlet I want to use a total pressure bc, but if I just export and import the pressure and velocity values I will loose the turbulence, right?
StefanG is offline   Reply With Quote

Old   June 28, 2012, 10:29
Default
  #8
Member
 
Peter Galimutti
Join Date: May 2012
Posts: 37
Rep Power: 13
p.galimutti is on a distinguished road
then try the last step in my previous post. it will initialize all the data! it's pretty easy...this is the screenshot of how you can use previous results using solver manager
Attached Images
File Type: jpg solver_manager.jpg (38.6 KB, 15 views)

Last edited by p.galimutti; June 28, 2012 at 12:51.
p.galimutti is offline   Reply With Quote

Old   July 2, 2012, 05:08
Default
  #9
New Member
 
Join Date: Mar 2012
Posts: 27
Rep Power: 14
StefanG is on a distinguished road
But the problem is, that in the combustion chamber the flow is completely subsonic, but if I interpolate the results from the whole flow channel, also the supersonic region in the flow channel will be taken into account, right?
StefanG is offline   Reply With Quote

Old   July 3, 2012, 09:05
Default
  #10
New Member
 
Join Date: Mar 2012
Posts: 27
Rep Power: 14
StefanG is on a distinguished road
Another question:

I have the problem that my y coordinate in the case from which I want to export the values of the plane differs from these I want to import them as my inlet boundary condition. Is it possible to make a coordinate transformation when I want to import the values?
StefanG is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
[Gmsh] Problem with Gmsh nishant_hull OpenFOAM Meshing & Mesh Conversion 23 August 5, 2015 03:09
ATTENTION! Reliability problems in CFX 5.7 Joseph CFX 14 April 20, 2010 16:45
New topic on same subject - Flow around race car Tudor Miron CFX 15 April 2, 2004 07:18
Symmetry Plane boundary conditions Tudor Miron CFX 1 March 17, 2004 01:12
A problem about setting boundary conditions lyang Main CFD Forum 0 September 19, 1999 19:29


All times are GMT -4. The time now is 03:03.