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

Laminar Stiff reacting flow won't converge

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 26, 2010, 13:26
Default Laminar Stiff reacting flow won't converge
  #1
New Member
 
Aaron
Join Date: May 2010
Posts: 4
Rep Power: 16
aarongoodwin is on a distinguished road
Hi all--
I am new to this CFD forum. I am currently working on a model that has a compressible fluid in laminar flow with a stiff reaction network. The flow has several stagnant or mixing regions in it. I am trying to solve this several ways.
The first was to approach it like in the Fluent manual and initialize a cold flow then add in the reactions. The second way was to use the unsteady coupled solver for pressure and reduce the Courant number to 100. The time step I used was 0.001 sec.

The mesh I have in the channel with the fluid is structured and I have 14 nodes in the vertical direction. I have not messed with the AMG settings but am not ad versed to it. Just got to figure out what makes sense.

The problem is I can't get the continuity residual below 0.1 even with no reactions. When I add the reaction network the problem takes more than a week to solve and the residuals for some of the species are not that great.

I have solved the model in a simple PFR and know the chemistry is correct.

any help on solver settings, AMG setting or different ways to tackle this would be awesome!
Aaron
aarongoodwin is offline   Reply With Quote

Old   March 13, 2012, 20:13
Default
  #2
Member
 
Nathan
Join Date: Aug 2010
Posts: 62
Rep Power: 16
natantyt is on a distinguished road
Hi

Any success on how to converge the reacting flow, I appreciate your suggestions.

Nat
natantyt is offline   Reply With Quote

Reply

Tags
compressible, laminar flow, reacting flow, stiff

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
boundary layer specifications for laminar flow ranjith CFX 7 October 16, 2017 09:09
Laminar doesn't converge; Turbulent models do? Amit FLUENT 11 April 23, 2015 23:55
Laminar Flow rvallejo CFX 1 November 16, 2009 10:49
no converge - for Low Re Porous media seepage flow lee CFX 3 August 31, 2007 02:12
CFD of laminar reactive liquid flow Ingo Meisel Main CFD Forum 5 March 12, 2004 05:38


All times are GMT -4. The time now is 08:25.