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

Will this global error cause me any problem?

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   February 9, 2006, 07:03
Default Will this global error cause me any problem?
  #1
Forrest
Guest
 
Posts: n/a
Hi all,

Here is the message: There are inconsistent radiation models specified for this problem. Radiative transport between domains requires the use of identical radiation models. If required, isolate domains by using the interface boundaries `Opaque' option instead of `Conservative Interface Flux'.

This message shows up when I turn on radiation for my fluid domain without turning it on for solid domains. CHT is modelled (without radiation) in the solid domains surrounded by the fluid domain. At interface boundaries, at solid domains, only one option â€" conservative interface flux; while fluid domain, two options - 'opaque' and conservative interface flux, so I set an emissivity under opaque option in order to represent the 'opaque' surface of the solids (bit confused here cos I thought I should be able to set it in the solid domains).The question is: do I model the radiation coming and going at the solid surfaces? If yes, should I just ignore the global error warning for this case to continue?

Thanks a lot

Forrest

  Reply With Quote

Old   February 9, 2006, 10:06
Default Re: Will this global error cause me any problem?
  #2
opaque
Guest
 
Posts: n/a
Dear Forrest,

You are fine.. It seems CFX-Pre is off on this check..

If a material is considered/modeled as Opaque, implies that radiation is absorbed in an infinitesimal layer near the boundary. Then, the radiation boundary condition for the fluid domain does not need to know there is a solid on the other side. It could even be an external wall with no CHT region..

Good luck, Opaque
  Reply With Quote

Old   February 9, 2006, 10:33
Default Re: Will this global error cause me any problem?
  #3
Forrest
Guest
 
Posts: n/a
opaque, thank you very much for your comments on this.

The solids I was modelling have a very small finite thickness (say 1.0mm), I only subdivide it by two cells since I don't expect big temperature gradient on that direction. It's a 2D modelling, there are more cells on the other direction (32 cells). During the simulation I noticed that the T-energy imbalance is oscillating all the time. I increased the solid time scales 100 times bigger than fluid, it still does the same. The T-energy imbalance in the other participating sold domains looks ok. Any suggestions about this?

Thank you again

Regards, Forrest
  Reply With Quote

Reply


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
Problem Importing Geometry ProE to CFX fatb0y CFX 3 January 14, 2012 20:42
Full pipe 3D using icoFoam cyberbrain OpenFOAM 4 March 16, 2011 10:20
Can I solve this problem by Fluent? Kai_kc FLUENT 1 October 27, 2010 06:29
natural convection problem for a CHT problem Se-Hee CFX 2 June 10, 2007 07:29
Adiabatic and Rotating wall (Convection problem) ParodDav CFX 5 April 29, 2007 20:13


All times are GMT -4. The time now is 18:52.