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

DPM injection mass problem

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

Like Tree1Likes
  • 1 Post By siramirsaman

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   August 22, 2016, 19:29
Unhappy DPM injection mass problem
  #1
New Member
 
Join Date: Dec 2010
Posts: 15
Rep Power: 15
siramirsaman is on a distinguished road
Hi,


I have an unsteady stream of multi-component particles being injected into turbulent flow. The problem is the mass of particles in parcel suddenly changes to a larger value after a couple of iterations.

After a point, diameter gets doubled while the number of particles in parcel gets divided by 8!

I have evaporation only. How is it possible for the mass in particle to get eight time larger?! Table below shows two sample particles from before and after increase in mass. I have tried the test case without coalescence and results are the same.




siramirsaman is offline   Reply With Quote

Old   August 23, 2016, 13:09
Default
  #2
New Member
 
Join Date: Dec 2010
Posts: 15
Rep Power: 15
siramirsaman is on a distinguished road
As it turns out, when KHRT breakup model is used this happens!

Apparently KHRT is only reliable for high Weber flows, I was injecting the particles way outside the fluid jet, I guess KHRT becomes unstable during particle's long flight outside the fluid jet where flow is slow.
SJSW likes this.

Last edited by siramirsaman; September 3, 2016 at 18:15.
siramirsaman is offline   Reply With Quote

Old   May 29, 2019, 23:52
Default
  #3
New Member
 
Mohammadreza
Join Date: Feb 2019
Posts: 3
Rep Power: 7
mrhaghighatjoo is on a distinguished road
Quote:
Originally Posted by siramirsaman View Post
As it turns out, when KHRT breakup model is used this happens!

Apparently KHRT is only reliable for high Weber flows, I was injecting the particles way outside the fluid jet, I guess KHRT becomes unstable during particle's long flight outside the fluid jet where flow is slow.
Hi,

I have the same problem as you. I am injecting particles into a turbulent, high Weber number gaseous medium. Exactly after injecting, the size of my injected particles roughly doubled, whereas the coalescence in stochastic collision option is also disabled. This issue does not happen to TAB breakup model, while for KHRT and wave breakup model are true. In fact, I have to use KHRT for my breakup, because in my case, after injection the medium is of low Weber number until reaching the focal point of gas stream and particles , i.e. high Weber number region and for me, the breakup model is important to get a better particle size distribution. I got stuck at this point. what can I do to resolve doubling in particle mass?
any help would be appreciated.
mrhaghighatjoo is offline   Reply With Quote

Reply

Tags
dpm convergence, dpm fluent model, dpm model, fluent

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
Multi Species Problem (mass fraction) usamaperwez CFX 0 July 27, 2016 08:07
How to calculate particle mass flow rate in domain with respect to injection flowrate Jeeloong Fluent Multiphase 0 January 27, 2016 20:40
dpm determine mass flow injection result kicunk FLUENT 0 July 11, 2013 06:25
combustion problem mcnair CFX 9 March 22, 2011 15:06
mass injection in a 2D axi-symmetric problem hyun Main CFD Forum 1 April 26, 2006 01:25


All times are GMT -4. The time now is 08:01.