CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT

Reaction in porous media - very slow convergence

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

LinkBack Thread Tools Search this Thread Display Modes
Old   November 27, 2015, 10:14
Default Reaction in porous media - very slow convergence
New Member
Laurien Vandewalle
Join Date: Jun 2013
Location: Ghent, Belgium
Posts: 29
Rep Power: 12
lavdwall is on a distinguished road
Hi there!

I am trying to simulate a honeycomb catalytic reactor by using the porous media model in Fluent. For the moment, I am using a small axisymmetric 2D grid and my reaction network only consists of 6 reactions (adsorption/desorption of O2 and CO, surface reaction to CO2, desorption of CO2). I use the steady-state pressure-based solver.

First, I run the case without reactions. It converges almost immediately.
Then I set the surface-to-volume ratio to 91000 for the porous zone and I run it again. However, it looks like the reaction does only proceed at the inlet of the porous zone, and the reaction front moves VERY SLOWLY through the reactor. I monitor the mole fraction of CO2 at the outlet and this increases slowly during the entire simulation.
The case reaches convergence after almost half a million iterations, which is way too much since my grid is only 45x30 cells. All underrelaxation factors are set to 1 so that is not the problem. There are no instabilities in the residuals.

Does anyone know this problem or has an idea how to solve it? Thanks in advance!

Kind regards,
lavdwall is offline   Reply With Quote


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
Porous media boundary conditions aggie FLUENT 3 June 17, 2012 09:51
Force can not converge colopolo CFX 13 October 4, 2011 22:03
Segmentation fault in running alternateSteadyReactingFoam,why? NewKid OpenFOAM 18 January 20, 2011 16:55
heat transfer to porous media... club68512 FLOW-3D 5 November 3, 2010 23:20
porous media with chemical reaction Arvind Phate FLUENT 2 July 18, 2005 13:52

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