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-   -   Particle tracking using fluent 5 (http://www.cfd-online.com/Forums/fluent/28565-particle-tracking-using-fluent-5-a.html)

John Beveridge May 29, 2001 10:52

Particle tracking using fluent 5
 
I am using fluent 5 to track particles down a 0.19m diameter pipe with a velocity of 0.6 m/s. Is there a limit to the size of particles I can accurately measure (i.e. 10% of diameter)? and do they have to be positioned at a certain distance away from the pipe wall (i.e. 0.5 diameter)?

Any help in this matter would be most appreciated. Thanks, John

rafi friend May 30, 2001 11:54

Re: Particle tracking using fluent 5
 
i think one thing you must do is setting the inlet sources completely (from surface, or from file, single etc. read fluent manual). but you can guess if you specify particle inlet with diameter 0.5 mm and 0.4 mm away from pipe wall. :)

John Beveridge June 4, 2001 05:25

Re: Particle tracking using fluent 5
 
Thanks Rafi, but I am really after the maximum size that a particle can be - obviously a particle can't be modelled well if it is 99% of the diameter of the pipeline. So what is the biggest it can be, and still be moved to a reasonable degree?

Althea June 6, 2001 09:08

Re: Particle tracking using fluent 5
 
Hello John,

Assuming that Lagrangian particle tracking is used (as per Fluent 4) then the volume fraction limit usually advised (in the papers I've read - sorry I have no references to hand) is about 12%. I would therefore translate this into a single particle with a diameter of less than 12% of the pipe diameter, or if several particles are simulated, the sum of their diameters should be less than 12% of the pipe diameter.

As is always the case, it is useful to have some reliable experimental data (or even hand calcs.) of a similar type of system, with which to compare the CFD to check you are in the right ballpark.

I hope this helps.

Regards

Althea

John Beveridge June 6, 2001 09:10

Re: Particle tracking using fluent 5
 
thanks for that! I appreciate your help in this matter

HGG June 13, 2001 11:53

Re: Particle tracking using fluent 5
 
Hi,Althea, If case is a converged-diverged pipe, do you mean the translated diameter should be less than 12% of diameter of samll section(throat of constricting part)?

thanks

Althea June 14, 2001 05:19

Re: Particle tracking using fluent 5
 
Yes, that seems reasonable. Althea


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