CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > FLUENT

Convergence troubles with 3D heat exchanger simula

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

Reply
 
LinkBack Thread Tools Display Modes
Old   June 12, 2008, 15:33
Default Convergence troubles with 3D heat exchanger simula
  #1
Balcazar - Capetillo
Guest
 
Posts: n/a
Hi everybody!

We are working in a 3D compact heat exchanger simulation (air - air) in Fluent. we have two rectangular ducts and between them some triangular fins. Inside rectangular ducts we set hot air (velocity, mass flow, pressure, temperature known) and over the fins flows cooling air (temperature and velocity known). We have serious converging problems, the residuals behavior is very rare. Do someone could advice us about initialization conditions and/or 3D models?

Thank you very much
  Reply With Quote

Old   June 12, 2008, 17:22
Default Re: Convergence troubles with 3D heat exchanger si
  #2
red lemon
Guest
 
Posts: n/a
set energy URF to 1 and dont reduce this. Allow explicit temperature under relaxation via TUI. Run as first order initially and cold than ramp up temperature gradually to full conditions. Ensure fins modelled as thin walls with shell conduction on and energy can get in and out of the domain ok.
  Reply With Quote

Old   June 13, 2008, 01:22
Default Re: Convergence troubles with 3D heat exchanger si
  #3
Balcazar - Capetillo
Guest
 
Posts: n/a
Thanks for your ans,

Well, we are not experts on modeling, so we dont know how to allow explicit temperature under relaxation via TUI. We have tutorials but these dont explain how to type commands to do that you recommended us. We obtained some results changing both boundary conditions at outlet to "pressure outlet" and assuming the conditions needed but this one arent clearly and reliable. Also, we have modeled some cases modifying the viscous model options. However, we have not found any results. Do you know any case that could be modeladed accurately for this kind of heat exchanger?

Thank you so much
  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
Troubles with heat release rate Xavier Ponticq CFX 4 September 12, 2012 18:49
heat exchanger pratap behera FLUENT 3 August 10, 2010 23:56
Convergence troubles guimch OpenFOAM Running, Solving & CFD 1 July 25, 2007 13:19
heat exchanger............. piyush FLUENT 0 January 22, 2007 09:00
Convective Heat Transfer - Heat Exchanger Mark CFX 6 November 15, 2004 16:55


All times are GMT -4. The time now is 07:06.