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

Turbulent Dispersion for Coal Combustion

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   February 16, 2010, 09:52
Default Turbulent Dispersion for Coal Combustion
  #1
Member
 
Reine Granström
Join Date: Apr 2009
Location: Sweden
Posts: 43
Rep Power: 17
gravis is on a distinguished road
Hi all,

I am looking at the possibility to use the model for Turbulent Dispersion for Lagrangian Tracking in my Ph.D. project which involves coal combustion.

I have read a number of articles on PF combustion using Fluent, where the turbulent dispersion model due to Gosman and Ioannides is included. As I understand this model is used in both CFX and Fluent, however I do not know if there are any differences in the implementation between the codes.

I have been in contact with a Ph.D. student who has done coal combustion simulations in Fluent using this turbulent dispersion model, and he did not recall any specific convergence issues related to using this model. From reading the CFX 12.1 documentation, it seems to me that applying the turbulent dispersion model is difficult task in regard to convergence behavior.

I have tested including turbulent dispersion to the Coal combustion tutorial included in CFX 12.1, but I did not manage to obtain a converged solution. However, I did not try to vary any parameters except for the Eddy Viscosity Ratio Limit which I increased step-wise up to 50 (default=5).

I have also tried simulating the turbulent dispersion for my own project, just using non-reacting particles with a reduced mass flow, which converges fine with just mean dispersion. I did not manage to obtain a converged solution for this case either.

My question is directed to anyone who has experience on this topic, if you have any recommendations what approach to take when including the turbulent dispersion model? Any model parameters that could be changed in a certain manner? Increasing the number of particle tracks, compared to what is sufficient for a mean particle dispersion simulation?

I would highly appreciate any thoughts on this.

Best regards,
Reine
gravis is offline   Reply With Quote

Old   March 23, 2010, 06:19
Default Follow-up
  #2
Member
 
Reine Granström
Join Date: Apr 2009
Location: Sweden
Posts: 43
Rep Power: 17
gravis is on a distinguished road
Does anyone have recommendations on values for the model parameters "pt minimum eddy life time" or "Eddy Viscosity Ratio Limit" with regard to easing convergence?

Best Regards
Reine
gravis is offline   Reply With Quote

Old   March 23, 2010, 23:56
Default
  #3
New Member
 
Dr. Flow Squad
Join Date: Mar 2009
Posts: 17
Rep Power: 17
Dr. Flow Squad is on a distinguished road
Contact Dr. Phil Stopford af Ansys CFX UK office.
Dr. Flow Squad is offline   Reply With Quote

Reply

Tags
coal combustion, convergence, turbulent dispersion

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
Question on turbulent dispersion force in momentum Emmery FLUENT 0 December 12, 2007 10:31
turbulent combustion palani kumar FLUENT 0 October 15, 2007 14:26
Lift & Turbulent Dispersion in Stirred Tank ozgur FLUENT 0 April 23, 2007 10:01
EDC, PDF transport and turbulent combustion HP FLUENT 6 March 30, 2005 03:00
NOx Formation in Turbulent hydrogen combustion Ali Yigit FLUENT 1 December 22, 2003 03:50


All times are GMT -4. The time now is 20:18.