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Old   June 5, 2005, 13:48
Default Help for Hydrocyclone
  #1
Nico
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Hi everybody.

I am a student and I try to modelling a water oil cyclone separator. But it still does not work. I have been blocked for one month.

Can you give me some advise please. I begin to despair. I don't know pressure at outlet. I tested in steady and unsteady, RSM and RNG k-eps, mixture and euler. Please help me.

Best regards
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Old   June 5, 2005, 14:40
Default Re: Help for Hydrocyclone
  #2
pUl|
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Please calm down and be specific. Exactly state your problem and someone might be able to help you out.
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Old   June 5, 2005, 17:57
Default Re: Help for Hydrocyclone
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Nico
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You're right. Calm down and be specific.

So, what I must use for modelling a hydrocyclone? Steady or unsteady? I am trying with steady. But after 5800 iterations I don't have convergence. Residual do that : http://arthagus.free.fr/perso/images/Stage/residus.jpg

I tested in unsteady. In this case, I do before a calculation in steady just with water. Residual go to 10-3 and after I change for unsteady with water and oil. My residuals converge and time of convergence is larger than the residence time, but oil don't leave the hydrocyclone.

I use RSM (I tested with RNGk-eps). My inlet are velocity inlet and my outlet are outflow (but I tested with an outflow for underflow and a pressure outlet for overflow). I am in PRESTO! and QUICK.

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Old   June 5, 2005, 23:34
Default Re: Help for Hydrocyclone
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thomas
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WHat multiphase model are you using ???
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Old   June 6, 2005, 04:50
Default Re: Help for Hydrocyclone
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Nico
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I use mixture as the fluent manual suggests it.
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Old   June 6, 2005, 10:49
Default Re: Help for Hydrocyclone
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thomas
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well effectively fluent manual suggest mixture model for oil water separation but not sure it is the best model in hydrocyclone cases ... Try other model like Euler Euler or the best would be DPM ... these model have better coupling with turbulent which may help your case ... fluent 6.2 has the possibility to do Euler-Euler + RSM, it is very heavy in time but you can give it a shot ! bonne chance
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Old   June 7, 2005, 05:29
Default Re: Help for Hydrocyclone
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Nico
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Thanks. I'm trying with k-eps and eleur multiphase model. But I have two other questions.

I use outlet pressure at overflow and outflow at underflow. In outflow boundary condition I leave the flow rate weighting to 1. It is correct?

I put under relaxation factors to 0.3 - 0.4. What think about it?

Best regards
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Old   June 16, 2005, 05:57
Default Re: Help for Hydrocyclone
  #8
Nico
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Steady or unsteady for my calculation? If there are unsteady phenomenon but that I calculate in steady (for deacrease calculation time), is this however a good approximation?

Best regards.
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Old   July 3, 2005, 04:25
Default Re: Help for Hydrocyclone
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ashish
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i wnat help on design of hydro cyclone for mining purposes
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Old   April 23, 2009, 09:28
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  #10
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santosh sakhare
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my problem statement is gas water separation in hydrocyclone... my basic problem is what value of under relaxation factors should be used...and what should be the best boundary conditions used for above problem. if i have change split ratio then what to do..i am using rsm as turbulence model.plz help me...thanks.
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