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

Particle size distribution DPM

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

Reply
 
LinkBack Thread Tools Display Modes
Old   August 21, 2012, 05:03
Default Particle size distribution DPM
  #1
Member
 
barzin
Join Date: Jan 2011
Posts: 33
Rep Power: 6
barzin is on a distinguished road
Hi everyone

Regarding particle size distribution in FLUENT the only available functions are Rosin Rameler (RR) and Uniform distribution. So what if I have my own distribution or even my own injection with a unique condition (e.g velocity, PSD,...). I was wondering if this can be introduce to FLUENT using a file injection?? If yes, how am I suppose to do that? what about the use of UDF? Can anyone explain this to me since I have a very vague vision of this. Your prompt suggestions are most appreciated
barzin is offline   Reply With Quote

Old   August 24, 2012, 05:37
Default
  #2
Senior Member
 
Join Date: Jun 2011
Posts: 108
Rep Power: 6
mali28 is on a distinguished road
Quote:
Originally Posted by barzin View Post
Hi everyone

Regarding particle size distribution in FLUENT the only available functions are Rosin Rameler (RR) and Uniform distribution. So what if I have my own distribution or even my own injection with a unique condition (e.g velocity, PSD,...). I was wondering if this can be introduce to FLUENT using a file injection?? If yes, how am I suppose to do that? what about the use of UDF? Can anyone explain this to me since I have a very vague vision of this. Your prompt suggestions are most appreciated
You can use several injections, each having a different size and different flow rate but injecting from the same location. That will make your own size distribution.
mali28 is offline   Reply With Quote

Old   August 24, 2012, 06:02
Default
  #3
Member
 
barzin
Join Date: Jan 2011
Posts: 33
Rep Power: 6
barzin is on a distinguished road
Quote:
Originally Posted by mali28 View Post
You can use several injections, each having a different size and different flow rate but injecting from the same location. That will make your own size distribution.
Hey mali

Thank you so much for your reply. This is a nice trick but do you think it is handy when you have a a very wide distribution. I mean hundreds of diameters??? How can this be done by a UDF?? Have you got any idea?
barzin is offline   Reply With Quote

Old   August 24, 2012, 06:17
Default
  #4
Senior Member
 
Join Date: Jun 2011
Posts: 108
Rep Power: 6
mali28 is on a distinguished road
Quote:
Originally Posted by barzin View Post
Hey mali

Thank you so much for your reply. This is a nice trick but do you think it is handy when you have a a very wide distribution. I mean hundreds of diameters??? How can this be done by a UDF?? Have you got any idea?
If you have a wide range of sizes, then you will need to add more bins. But if you add more bins then your simulation will become more computationally expensive. So it has to be a compromise between computational time and accuracy. You can check the sensitivity of results on the number of discrete sizes (bins).
And select the one which is the best compromise between the computational time and accuracy.
mali28 is offline   Reply With Quote

Old   August 24, 2012, 06:36
Default
  #5
Member
 
barzin
Join Date: Jan 2011
Posts: 33
Rep Power: 6
barzin is on a distinguished road
Is this "Bin" defined by "Number of diameters" in the injection properties dialogue box? If yes the only particle size distribution which includes this feature is Rosin Ramler. So if I select RR for my injections again the overall distribution will be RR? am I right?
barzin is offline   Reply With Quote

Old   August 24, 2012, 07:03
Default
  #6
Senior Member
 
Join Date: Jun 2011
Posts: 108
Rep Power: 6
mali28 is on a distinguished road
Quote:
Originally Posted by barzin View Post
Is this "Bin" defined by "Number of diameters" in the injection properties dialogue box? If yes the only particle size distribution which includes this feature is Rosin Ramler. So if I select RR for my injections again the overall distribution will be RR? am I right?
Yes, bin is defined by number of diameters. You also check the simulation sensitivity with the number of parcles (tracks) for each discrete size.
Fluent only offers Rosin-Rammler distribution. Log-normal distribution can also be used but it is not available in Fluent.
mali28 is offline   Reply With Quote

Old   August 24, 2012, 07:30
Default
  #7
Member
 
barzin
Join Date: Jan 2011
Posts: 33
Rep Power: 6
barzin is on a distinguished road
Right, cool. Thanks a lot for your time mate
barzin is offline   Reply With Quote

Old   February 27, 2014, 06:07
Default
  #8
New Member
 
Join Date: Feb 2014
Posts: 3
Rep Power: 3
chang is on a distinguished road
Quote:
Originally Posted by mali28 View Post
Yes, bin is defined by number of diameters. You also check the simulation sensitivity with the number of parcles (tracks) for each discrete size.
Fluent only offers Rosin-Rammler distribution. Log-normal distribution can also be used but it is not available in Fluent.
What if i want to obtain Log-normal distribution? through the UDF or use R-R instead? Thanks!
chang is offline   Reply With Quote

Reply

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
DPM particle tracking in stirred tank parisa- FLUENT 1 August 7, 2012 12:03
[ICEM] Help with fixing imported IGES model siw ANSYS Meshing & Geometry 24 August 24, 2010 11:22
Steady state DPM - Convergence and particle tracks Sandilya Garimella FLUENT 2 March 28, 2008 16:53
fluent add additional zones for the mesh file SSL FLUENT 2 January 26, 2008 12:55
Particle Size Distribution with R-R fails? HP FLUENT 6 May 19, 2005 06:35


All times are GMT -4. The time now is 05:37.