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DPM Diameter querry

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Old   August 16, 2010, 22:00
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Mohsin Mukhtar
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I am using DPM surface injection from inlet whose sides are 0.82*0.89 m. But when i inject particles of 10 m diameter still i get the resullt at the outlet. why is it so??? How can a particle enter into a duct having bigger dimensions than the duct? Aren't I supposed to get an error??

Your urgent response will be highly appreciated.

Mohsin
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Old   August 16, 2010, 22:37
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DPM model is a Euler-Lagrangian multiphase flow model, that is, the discrete phase is considered as particles no matter how big it is, only the trajectory of the centroid is cumputed.
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Old   August 16, 2010, 22:43
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Mohsin Mukhtar
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Thanks for your reply

As far as i know in the langrangian method the particles are tracked while in Eulerian method fixed point is taken and particles are not followed.

Dpm uses Langrangian formulation but How can a trajectory be calculated if the diameter of the particle is larger than the duct in which it is moving? could u please elaborate.
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Old   August 16, 2010, 23:00
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In real world it is impossible for the diameter of a particle larger than the duct. So, in the computer, if you build a computation model like that, the mistake is brought about by you, not by the computer or the DPM model. You built a wrong model with a improper method.
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Old   August 16, 2010, 23:04
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ok so i will assign the diameters according to the streams I m sending in. for exapmple for group injection of 5 streams in a duct of 5m, I will assign a diameter starting to end point as 0.1 so that each particle stream has 0.1 diameter and it should remian in the domain. otherwise if i assign a diameter of 0.2 fluent will still calualte it but as u mentioned it would contradict with the real world problem and would have errors.

If i m wrong please let me know. Thanks for your time.
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