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

Problem on EDC model for coal combustion

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

LinkBack Thread Tools Search this Thread Display Modes
Old   March 9, 2010, 19:25
Smile Problem on EDC model for coal combustion
New Member
Lei Chen
Join Date: Mar 2010
Posts: 21
Rep Power: 16
lei is on a distinguished road
Dear friends,
I am having a difficult time working on EDC model with coal combustion. My case is a 2d and 3d coal-fired combustor, and the model configurations are as follows:
*Pressure based solver
*k-epsilon turbulence model
*CPD for coal devolatilization
*volatiles decompose into CO, H2, Hydrocarbons (a global reaction)
*surface reactions for char oxidation
*JL 4-step mechanism for hydrocarbon combustion (I double checked the reaction rates units and constants, they should be right)
*defult settings for EDC model
*operating condition 4 bar
Before trying to use EDC, I used Finite Rate/Eddy Dissipation model for the turbulent-chemistry interaction in both 2d and 3d case, and it seems reasonable. I would try to use EDC because it allows reversible reaction, and seems more advanced by considering kinetics rates in fine scale.
But when I swich to the EDC model, the combustion temperature drops gradually from 1900 K to the inlet temperature, which indicates no reaction at all. The CO concentration is as high as 10%, which meas devolatilization, char oxidation take place, however CO oxidation doesn't take place.
Even when I added a CO reaction CO+0.5O2->CO2, and remain the wall temperature as 1900 K, the outlet temperature is high (~1820 K), but CO is still there.
Could you kindly help on this if you have experience with EDC model, especially when use it with coal combustion?
My questions:
1) Is EDC compatible with DPM, or coal combustion? (it should be, as said in the user guide, and some people used it in some publications)
2) What may be the problems caused this high CO concentration?
Thank you so much!

Last edited by lei; March 9, 2010 at 19:37. Reason: give more information
lei is offline   Reply With Quote

Old   March 17, 2011, 11:29
Default Smile Problem on EDC model for coal combustion
New Member
wwa's Avatar
Join Date: May 2009
Location: France
Posts: 14
Rep Power: 17
wwa is on a distinguished road
it is possible that high temperature is the reason of your problem. 1800 K at the outlet seems to be quite high. If your reactions are reverse as you said, CO2 dissociates to make CO more dominant. You can try to modify your boundary conditions to reduce temperature for example.

and DPM with EDC is compatible. i didn't have any troubles using it.

wwa is offline   Reply With Quote

Old   March 18, 2011, 01:06
Byron Smith R J
Join Date: Mar 2009
Location: India
Posts: 46
Rep Power: 17
byronsmith is on a distinguished road
check the air fuel ratio too
byronsmith is offline   Reply With Quote

Old   April 29, 2014, 08:55
Maaz Ul Mosaid
Join Date: Jan 2014
Location: Pakistan
Posts: 32
Rep Power: 12
maazulmosaid is on a distinguished road
please send me eddy break up model files on
maazulmosaid is offline   Reply With Quote

Old   September 3, 2015, 09:39
Default Coal Combustion CPD Devolatilization model warning message in Fluent
New Member
Saurav Chakraborty
Join Date: Sep 2013
Posts: 14
Rep Power: 12
srv1406 is on a distinguished road
With reference to the CPD model for coal devolatilization can anyone please tell me about the warning i get during every DPM iteration:

CPD--Last two guesses for v/f were: -1.#IND00 -1.#IND00 CPD--Convergence not achieved in flash distillation.

Is it an error message or can we ignore it..
If it is an error what can be the possible cause
srv1406 is offline   Reply With Quote


coal combustion, edc

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
Nonpremixed Combustion Model for Coal Gasification C.Y.Ler FLUENT 2 April 29, 2014 08:51
Liquid rocket engine non-premixed combustion model Erik FLUENT 2 November 28, 2013 14:09
Does EDC Combustion Model Work? A. FLUENT 0 September 15, 2005 04:43
Weller combustion model roadracer Siemens 0 October 6, 2003 05:07
combustion problem cindy FLUENT 5 September 4, 2000 19:00

All times are GMT -4. The time now is 21:52.