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

defining-particle size distribution-in cfx

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

Reply
 
LinkBack Thread Tools Display Modes
Old   April 30, 2012, 09:58
Default defining-particle size distribution-in cfx
  #1
New Member
 
krish
Join Date: Apr 2012
Posts: 5
Rep Power: 5
harry39 is on a distinguished road
hello all,

i am doing two phase flow simulations in ansys cfx.while initialization of boundary conditions at inlet in particle behaviour tab..i have to mention the particle size distribution with a user specified discrete diametr distribution function.i have functions for both mass fraction and number fraction as a function of diameter.
how can i insert the diameter list...? and mass fraction list & number fraction list.....as a function of diameter..?

advance thanks
krish
harry39 is offline   Reply With Quote

Old   April 30, 2012, 19:52
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,665
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
This is covered in the tutorials on particle flows.

And please do not PM me when you have already posted the identical question on the forum.
ghorrocks is offline   Reply With Quote

Old   May 1, 2012, 02:14
Default
  #3
New Member
 
krish
Join Date: Apr 2012
Posts: 5
Rep Power: 5
harry39 is on a distinguished road
Quote:
Originally Posted by ghorrocks View Post
This is covered in the tutorials on particle flows.

And please do not PM me when you have already posted the identical question on the forum.
thank you for your reply...and i dont send private msg to you sorrry for that.
can you please tell me where can i get those tutorials on particle flows...?

thanks again
krish
harry39 is offline   Reply With Quote

Old   May 1, 2012, 19:00
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,665
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
The tutorials are in the help files, and the example files are in <CFX_ROOT>/examples
ghorrocks is offline   Reply With Quote

Old   May 4, 2012, 05:26
Default
  #5
New Member
 
krish
Join Date: Apr 2012
Posts: 5
Rep Power: 5
harry39 is on a distinguished road
Quote:
Originally Posted by ghorrocks View Post
The tutorials are in the help files, and the example files are in <CFX_ROOT>/examples
thanks glenn for your reply,

I am getting an error while running in cfx solver.. like " wall is placing at outlet boundary " ....error is occuring some times up to 10 iterations and more..i have tried expert parameter control..artificial buid also..but no use..still getting...problem..
can any body suggest me, what it means & how can i rectify it ? (or) Does it mean that any problem while defining the physics in ccl file... (or) in geometry ?

thanks
krish
harry39 is offline   Reply With Quote

Old   May 4, 2012, 06:47
Default
  #6
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,665
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
It is not an error, it is a warning. It simply means you are getting backflow at your outlet. If it does not go away you should move your outlet downstream.
ghorrocks is offline   Reply With Quote

Old   May 4, 2012, 08:37
Default
  #7
New Member
 
krish
Join Date: Apr 2012
Posts: 5
Rep Power: 5
harry39 is on a distinguished road
Quote:
Originally Posted by ghorrocks View Post
It is not an error, it is a warning. It simply means you are getting backflow at your outlet. If it does not go away you should move your outlet downstream.
thanks again glenn for you reply,

" U mean that i have to extend my outlet geometry to rectify the problem...? or Can i neglect the warning and proceed my my simulations...?"

and one more thing is.. i have mentioned in the previous posts about defining discrete droplet size distribution..i think you havent understand my problem properly...
the point is i have data file of diameter list say for example: 10,20,30,..100 microns
i want to upload this list file to the diameter list and then i have an expression for both number fraction and mass fractions as a function of diameter,
for example: mf(mass fraction) (or) NF(number fraction)=Constant value(units are length)/Diameter
so after uploading the diameter list and these expressions it should calculate mf and Nf values for each diameter in the diameter list
so my questions are
1) how can i upload a list of values data file in to solver?
2)and how to write expressions to calculate the value for each data value in the above uploaded list ?

waiting for your valuable suggestions ....

thanks
krish
harry39 is offline   Reply With Quote

Old   May 5, 2012, 07:08
Default
  #8
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,665
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Read the documentation on this issue. But in general it is a good idea to move the boundary further down stream when this warning occurs.

It has been a while since I set particle distributions like that but I recall it can be done. Have a read of the documentation.
ghorrocks is offline   Reply With Quote

Reply

Tags
size distribution

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
Pls help UDF about particle size (Rosin-Rammler) ch3coohminh Fluent UDF and Scheme Programming 7 December 28, 2011 11:09
Particle Size Distribution (PSD) in fluidization sangramroy FLUENT 3 November 2, 2011 05:19
DPM model, droplet size distribution in atomizer model davidx FLUENT 2 November 13, 2010 03:43
particle size distribution Bob FLUENT 6 January 29, 2004 20:32
Particle size distribution-concentration contours Umesh Shah FLUENT 3 July 22, 2003 14:46


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