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

trying to simulate two-phase jet flow with particles in surface injection

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

Like Tree3Likes
  • 1 Post By ajkratos
  • 1 Post By Amir
  • 1 Post By ajkratos

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 21, 2011, 12:21
Default trying to simulate two-phase jet flow with particles in surface injection
  #1
New Member
 
Join Date: Dec 2010
Posts: 13
Rep Power: 15
ajkratos is on a distinguished road
Hi
I am trying to simulate two-phase jet flow. I use my inlet surface which is 0.1x0.1 to inject particles. Mass loading is 0.1, diameter of the particle is 7.69E-04m and the total mass flow rate of particles is 0.01225 kg/s. Using this data i calculated i need to inject 7.04E+04 particles to achieve the mass loading of 0.1. But in surface injection, the number of particles injected are equal to number of cell faces on that surface which in my mesh are 25.
I do know that i can increase the number of particles by creating a surface and samples on that surface which will be equal to number of particles, or/and and i can switch on the stochastic tracking in which case No. of tries are multiplied to the number of particles released by the surface.
my question is what is the significace of specifying mass flow rate in point properties tab of DPM, how does it effect the number of particles injected? As i increase or decrease the value of total mass flow rate of particles, the number of particles remain same= No of mesh faces. Soo why does fluent need the total mass flow rate of particles. Also if i switch on stochastic tracking and increase the number of tries just to increase the number of particles, what other implications will it have other than increasing the number of particles?
I will really appreciate if sumone culd help, i urgently need to clear this. Thanks
ajkratos is offline   Reply With Quote

Old   March 21, 2011, 15:00
Default
  #2
Senior Member
 
Amir's Avatar
 
Amir
Join Date: May 2009
Location: Montreal, QC
Posts: 735
Blog Entries: 1
Rep Power: 23
Amir is on a distinguished road
Hi,
the particle mass flow rate doesn't change the No. of particle streams but it implicitly affect particle numbers in the flow field. you can imagine each stream as a sequence of specified particles and you can change that by changing mass flow rate.
in finding particle trajectories, the mass flow rate doesn't play a role but in particle concentration concepts it's very important.
Amir is offline   Reply With Quote

Old   March 22, 2011, 07:21
Default
  #3
New Member
 
Join Date: Dec 2010
Posts: 13
Rep Power: 15
ajkratos is on a distinguished road
Quote:
Originally Posted by Amir View Post
Hi,
the particle mass flow rate doesn't change the No. of particle streams but it implicitly affect particle numbers in the flow field. you can imagine each stream as a sequence of specified particles and you can change that by changing mass flow rate.
in finding particle trajectories, the mass flow rate doesn't play a role but in particle concentration concepts it's very important.
Hi Amir thanks for your helpful reply. How do i determine the totall No. of particles being ejected? Am i right to understand that each particles stream represent No. of particles according to the totall mass flow rate specified in point properties? I have 25 mesh faces on the inlet surface so there are 25 particles streams being ejected. If i divide the total mass flow rate by 25 is it correct to say that i will get mass flow rate of each stream and then i can calculate No. of particles in each stream by
No of particles in each stream= mass flow rate of stream/mass of single particle

Also in my case the diameter of all particles is same and the distribution is uniform.
hassansalem likes this.
ajkratos is offline   Reply With Quote

Old   March 22, 2011, 07:43
Default
  #4
Senior Member
 
Amir's Avatar
 
Amir
Join Date: May 2009
Location: Montreal, QC
Posts: 735
Blog Entries: 1
Rep Power: 23
Amir is on a distinguished road
Hi,
If you divide the total mass flow rate by 25; you'll obtain mass flow rate of each stream.
so i correct your statement:
No of particles in each stream= (mass flow rate of stream/mass of single particle)*(the time of first particle tracking in each stream)

so it's dimension is also correct.
hassansalem likes this.
Amir is offline   Reply With Quote

Old   March 22, 2011, 10:32
Default
  #5
New Member
 
Join Date: Dec 2010
Posts: 13
Rep Power: 15
ajkratos is on a distinguished road
yes ofcoarse i meant number of particles in 1 second. Thank you very much amir, you have been very helpful
hassansalem likes this.
ajkratos is offline   Reply With Quote

Old   March 3, 2015, 21:33
Default
  #6
New Member
 
Zhimin Zheng
Join Date: Mar 2015
Posts: 3
Rep Power: 11
zhengjimi is on a distinguished road
Quote:
Originally Posted by Amir View Post
Hi,
If you divide the total mass flow rate by 25; you'll obtain mass flow rate of each stream.
so i correct your statement:
No of particles in each stream= (mass flow rate of stream/mass of single particle)*(the time of first particle tracking in each stream)

so it's dimension is also correct.
Are you sure that No of particles in each stream=total flow rate /truck numbers/ mass of single particle(NO/s)?

But I can not understand that meaning of P_FLOW_RATE(p)?
Thanks for your help ?
zhengjimi is offline   Reply With Quote

Reply

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
Three Phase flow into a reservoir... akjha Main CFD Forum 0 December 15, 2014 07:01
Cluster ID's not contiguous in compute-nodes domain. ??? Shogan FLUENT 1 May 28, 2014 15:03
how to simulate jet flow? Benny FLUENT 18 May 12, 2014 10:53
How to define the diameter for second phase in Eulerian model in free surface flow boa7128 Fluent Multiphase 1 December 14, 2013 06:20
injection problem Mark New FLUENT 0 August 4, 2013 01:30


All times are GMT -4. The time now is 06:29.