
[Sponsors] 
August 27, 2010, 22:37 
Particle Tracking

#1 
New Member
Przemek
Join Date: Feb 2010
Location: Warsaw Poland
Posts: 25
Rep Power: 9 
Hi,
I have question about Particle Tracking Model. In steady state. Assuming that we have information about particle diameter, particle material density and particle mass flow rate, we can evaluate number of real particles flowing into the domain per unit of time. So, if we provide number of representative particles (Number of Positions) and we divide number of real particles by number of representative particles, we can evaluate how many real particles each representative particle reprasents. Dimension of these value is [1/unit of time], am I right? But, in documentation it is written: "For steady state simulations, the Number of Positions parameter sets the total number of particles to be injected". So, it is a finite value? There is no constant number of particles flowing per unit of time? Thanks for answers, Batis 

October 4, 2010, 08:00 

#2 
Member
Rain
Join Date: Apr 2009
Posts: 40
Rep Power: 9 
As you said, in a steady state simulation you set a fixed number of tracks to represent the mean particle paths. In a transient simulation, you set the number rate of particle tracks injected  [1/unit of time].
In both cases, you also specify e.g. the particle size distribution and the total mass flow rate of all tracks. So, in a steady state simulation, you don't directly specify a constant number of particles flowing per unit of time. However, indirectly you specify the mass flow rate for each particle track. Consequently, by specifying the particle size distribution you also are indirectly specifying the number rate per track. if you know the mass flow rate of particles you can calculate the mass flow rate per particle track. And if you know the size distribution it is possible to calculate the number of particles flowing per unit time. To answer your question, yes there is a constant number of particles flowing per unit time, provided that you specify a mass flow rate and a particle size distribution. Last edited by gravis; October 4, 2010 at 08:51. Reason: Clarification 

October 6, 2010, 15:20 

#3 
New Member
Przemek
Join Date: Feb 2010
Location: Warsaw Poland
Posts: 25
Rep Power: 9 
Ok, thanks for reply.
Batis 

Thread Tools  
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
particle tracking  Wenqing Zhang  CFX  15  August 3, 2013 06:02 
particle tracking in unsteady flow  peterchen  FLUENT  1  July 22, 2010 22:18 
Number density tracking rather than particle tracking  Rebecca  Main CFD Forum  2  April 23, 2009 12:52 
DPM UDF particle position using the macro P_POS(p)[i]  dm2747  FLUENT  0  April 17, 2009 01:29 
restarting lagrange (particle tracking) simulation  dbdias  CFX  0  September 22, 2007 19:26 