
[Sponsors] 
November 25, 2004, 20:51 
Two way coupling in DPM

#1 
Guest
Posts: n/a

Sponsored Links


Sponsored Links 
November 26, 2004, 07:17 
Re: Two way coupling in DPM

#2 
Guest
Posts: n/a

If your particles all have the same mass, then the number concentration is proportional to the mass concentration, and you could write a simple custom field function.
As for the whole collision thing, I think it's probably possible, but it's gonna be a serious piece of work. The trick will be locating when collisions occur, particularly if the size of the particle is small compared to the size it can move in any given time step, and/or the frequency of collisions is high. Good luck Rob 

November 27, 2004, 21:30 
Re: Two way coupling in DPM

#3 
Guest
Posts: n/a

"inlet solid mass loading is 0.0533,and the solid volume fraction is 2.36e5" You dont neccesary have a twoway coupling at those conditions. The mass loading is actually not very high, it is in the upper range of one way coupling or lower range of twoway. The coupling also depends on the Stokes number, i.e. the the particle response time (depends on the density of your particles, diameter, viscosity, etc.) and a global time scale. I do not understand why you multiply the drag with a factor ...., why is it neccesary? Regards Jan


November 28, 2004, 23:47 
Re: Two way coupling in DPM

#4 
Guest
Posts: n/a

Thanks for your answering my questions. To Rob Unfortunately in my simulation, particles have RosinRommler distribution, so I don¡¯t know how to deal with this. In addition, as for collision, I only consider particles collision between the current cell and its adjacent ones, and each cell has one or two particles, because I use the numerical particles (i.e. one numerical particle stands for many particles). My question is that how I can get the particles¡¯ information which is in the adjacent current cell. Hope you can give me some advice, thanks very much. To Jan I know as for my question, sometimes oneway coupling is enough, but I want to extend the range of my question, so I have to use the twoway coupling. Elghobashi (1994) has mapped the interaction between particles and turbulence by means of two characteristic dimensionless quantities, viz. the volume fraction of particles, and the ratio of the particle response or relaxation time, and the Kolmogorov time scale. When the volume fraction of particles is 2.36e5, the momentum transfer from the particles is large enough to alter the turbulence structure, so I have to consider the twoway coupling. After considering the twoway coupling, the velocity of gas phase should be damped, although the turbulence intensity may be not change. I don¡¯t know why my simulation has not this result. Why do I multiply the drag with a factor much bigger than 1? I think I can view the individual numerical particles as parcels and enhance the influence of the particles on the gas flow field by means of this method. Maybe not right, welcome you give me some advice. Thanks in advance. Best regards to you, fpingqian


Thread Tools  
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Simple Behavioural Models: Fluid Coupling  Chromatix  Main CFD Forum  0  February 20, 2010 17:17 
What is weakstrong coupling in FSI problems  hajo  OpenFOAM Running, Solving & CFD  5  May 15, 2008 01:45 
one/two way coupling of DPM  Angela  FLUENT  3  April 28, 2008 09:29 
slow after mesh for enhanced wall treat DPM  joshkemp  FLUENT  0  May 1, 2007 17:20 
DPM coupling steps  kiao  FLUENT  5  June 23, 2005 11:04 
Sponsored Links 