CFD Online Logo CFD Online URL
Home > Forums > FLUENT

Error: update_absorption_coefficient: CO2 not defined

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

Like Tree1Likes
  • 1 Post By NormalVector

LinkBack Thread Tools Display Modes
Old   October 10, 2012, 15:11
Default Error: update_absorption_coefficient: CO2 not defined
NormalVector's Avatar
Join Date: Oct 2010
Posts: 72
Rep Power: 9
NormalVector is on a distinguished road
Hey all,

I'm working on a combustion problem and I'm trying to incorporate thermal radiation, specifically the discrete ordinates (DO) model. After doing some research, I wanted to try out the WSGGM method for specifying absorption coefficients. From what I understand, Fluent grabs values from an internal database.

Well, when I go to initialize the solution (with WSGGM specified), Fluent gives me an error: "update_absorption_coefficient: CO2 not defined". It seems CO2 may be missing from the internal database. What's weird is there is no CO2 in my domain at all...

Is there any way to remedy this situation? Maybe there is a place to define this "update absorption coefficient"?
NormalVector is offline   Reply With Quote

Old   October 10, 2012, 16:41
NormalVector's Avatar
Join Date: Oct 2010
Posts: 72
Rep Power: 9
NormalVector is on a distinguished road
I think I've figured out the problem. According to the Fluent User's Manual in regards to the absorption coefficient,

"FLUENT also allows you to input a composition-dependent absorption coefficient, with the local value of a function of the local mass fractions of water vapor and carbon dioxide. This modeling option can be useful for simulation of radiation in combustion applications. The variable-absorption-coefficient model used by FLUENT is the weighted-sum-of-gray-gases model (WSGGM) described in Section 13.3.8. To activate it, select wsggm-cell-based, wsggm-domain-based, or wsggm-user-specified in the drop-down list to the right of Absorption Coefficient in the Materials panel. The three WSGGM options differ in the method used to compute the path length, as described below.

(Remember that you must first enable the species calculation in order to see the wsggm choices in the list, and CO2 and H2O must be present in the mixture.)"

My reaction doesn't produce CO2 but when I add it into the mixture materials and initialize with a 0 mass fraction of CO2, Fluent allows the initialization.
mackr likes this.
NormalVector is offline   Reply With Quote


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
[ICEM] How can I define different zones in ICEM? llrr ANSYS Meshing & Geometry 14 February 12, 2017 14:44
CO2 concentration simulation angierain CFX 7 May 2, 2016 16:51
OpenFOAM static build on Cray XT5 asaijo OpenFOAM Installation 9 April 6, 2011 12:21
OpenFOAM13 for Mac OSX Darwin 104 hjasak OpenFOAM Installation 70 September 24, 2010 05:06
User Defined Scalars - Returning Values Carlos V. FLUENT 0 April 19, 2006 18:18

All times are GMT -4. The time now is 13:44.