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October 25, 2009, 04:47 
Contaminant Removal By Ventilation

#1 
Member
Primoz Ternik
Join Date: Apr 2009
Location: Maribor, Slovenia
Posts: 65
Rep Power: 9 
Using OF1.5 I would like to simulate the removal of contaminant by means of ventilation (forced convection). The first idea (approach) is to model the flow of air + additional scalar equation for contaminant (here, the scalar will be used as a "tracer" for contaminant concentration). I have already (and successfully) included additional scalar equation in the OF1.5 solver and set the "initial field" for contaminant (similar to the "DamBreak" tutorial case) for the simple flow in a straight channel...
Now, I would like to move to the next step (figuratively presented in attachment), which involves the following:
Primoz. 

October 25, 2009, 08:36 

#2 
Senior Member
Fabian Braennstroem
Join Date: Mar 2009
Posts: 407
Rep Power: 11 
Hi Primoz,
maybe the attached solver helps. It works for 1.6.x is mainly work smoke distributions with no testing ... yet :) Hope this helps a bit and would be nice to see yours running... Fabian 

October 25, 2009, 14:49 

#3  
Member
Primoz Ternik
Join Date: Apr 2009
Location: Maribor, Slovenia
Posts: 65
Rep Power: 9 
Quote:
thanks for the solver! But at the moment I am facing "conceptual" problems (see my previous post), i.e.:
If you (or anybody else) can help how to overcome these issues I am more than thankfull! I think that implememtation of the correct solver for this case (standard solver with some modiciations if neccessary) is just the matter of approach (academic or industrial)  my current oppinion is that removal of contaminat is mostly governed by the forced convection... Of course, influence of natural convetction can be an upgrade of this (first) step! With best wishes, Primoz. 

October 25, 2009, 16:46 

#4 
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Fabian Braennstroem
Join Date: Mar 2009
Posts: 407
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Hi,
you should take a look at the solver. The definition of a volume source region is done using dictionaries see attached case. Fabian 

October 25, 2009, 21:39 

#5 
New Member
Kurt Pudniks
Join Date: Sep 2009
Location: Australia
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this is a very interesting problem to me, i'd like to hear how you go if you can solve it!
it would suit the study of fires with smoke and chemical spills indoors and how much work a fan might need to do to return the air to a breathable ratio...? 

October 26, 2009, 02:40 

#6  
Member
Primoz Ternik
Join Date: Apr 2009
Location: Maribor, Slovenia
Posts: 65
Rep Power: 9 
Quote:
thanks again! Now I am getting the point for sources in a volume region! I will try the proposed approach and will keep you posted with results. Cheers, Primoz. 

October 26, 2009, 02:47 

#7  
Member
Primoz Ternik
Join Date: Apr 2009
Location: Maribor, Slovenia
Posts: 65
Rep Power: 9 
Quote:
thanks for showing interest on this problem. Indeed, this aims to model different scenarios where ventilation system (type, number and placement of ventilators) is used to avoid "human damage". If (or better said when) I will have progress with this subject, I will keep you informed... Regards, Primoz. P.S.: if you (or anybody else) have some articles (or other open literature) on this subject I will be extremely thankful if you can send them to me! 

October 27, 2009, 05:48 

#8  
Member
Primoz Ternik
Join Date: Apr 2009
Location: Maribor, Slovenia
Posts: 65
Rep Power: 9 
Quote:
I tried to follow "your recipe" (regarding the explicit source terms), but unfortunately something is not working... To be honest, it is my low level of experience with OpenFoam1.5 that is responsible for that. In a first approach I am using "turbFoam" which was modified with inclusion of additional scalar equation for "smoke"  so far so good . But when I try to define "explicit source term for smoke (which is scalar)"... Can you (or anybody else), please, see the attached case and help me with a definition of an explicit source term! Currently I am using the setFields utility for initial values of scalar, but I would like to do this via source terms... Thanks in advance, Primoz. 

November 23, 2009, 08:22 

#9 
New Member
Fabian Korn
Join Date: Mar 2009
Location: Heilbronn, Germany
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Hi Ternik,
how are you doing with your problem? Actually i have the same kind of problem ventillation with a smoke source and i was wondering if it is possible to use a buoyant solver. Do you think this could work out? Regards Fabian 

November 26, 2009, 07:37 

#10  
Member
Primoz Ternik
Join Date: Apr 2009
Location: Maribor, Slovenia
Posts: 65
Rep Power: 9 
Quote:
at the moment "this problem" is on standby!!! About the buoyant solver  it depends what you would like to "capture" with numerical modelling. In my first approach I am looking to be able to model this by solving additional transport scalar equation (for smoke)! I have done this, but as a next step I would need (or to be able):
Cheers, Primoz. 

March 18, 2010, 09:28 

#11 
Member
Aniko Rakai
Join Date: Oct 2009
Location: Geneva
Posts: 30
Rep Power: 8 
Hello,
I think timeActivatedExplicitCellSource is something that could help you, I'm trying to solve a similar problem and I found this at src/finiteVolume/cfdTools/general/fieldSources/, it writes: Creates a cell set source that is activated at a given time, and remains active for a specified duration. The source value is either in specific (XX/m3) or absolute (XX) units. My only problem is that I haven't found any notes or tutorials on how to use that, I will post if I manage, I hope you find it interesting. 

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