CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM

Contaminant Removal By Ventilation

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   October 25, 2009, 04:47
Default Contaminant Removal By Ventilation
  #1
Member
 
Primoz Ternik
Join Date: Apr 2009
Location: Maribor, Slovenia
Posts: 65
Rep Power: 8
ternik is on a distinguished road
Using OF-1.5 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 OF-1.5 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:
  • The ventilator is placed inside the fluid domain (for example in a room) - I have tried to do this with blockMesh utility, but I am having problems with definition of internal region as well as "internal walls" (walls that bound the ventilator). How can I overcome this issue (define an internal region with two walls so the "wall boundary conditions" are taken into account)?
  • For the "ventilator region" I would like to add an extra explicit source term (known pressure drop) to the momentum equation - I think this is possible with "timeActivatedExplicitSource.C", but due to my lack of OF experience I do not know exactly what has to be done... Can someone help me, please?
  • Instead of the contaminant "initial filed" I would like to add the explicit source term to the scalar transport equation and this surce term would be "switched on & off" at predifined times (e.g. scalar source is active only in a certain region for a certain period of time). Again, I think this is possible with "timeActivatedExplicitSource.C", but for the same reason (lack of experience with OF) I kindly ask you for your assistance...
Your help, tips and ... is highly appreciated,
Primoz.
Attached Files
File Type: pdf Ventilation.pdf (3.2 KB, 83 views)
ternik is offline   Reply With Quote

Old   October 25, 2009, 08:36
Default
  #2
Senior Member
 
Fabian Braennstroem
Join Date: Mar 2009
Posts: 407
Rep Power: 10
braennstroem is on a distinguished road
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
Attached Files
File Type: zip buoyantPisoFoamRadiation.zip (6.0 KB, 45 views)
braennstroem is offline   Reply With Quote

Old   October 25, 2009, 14:49
Default
  #3
Member
 
Primoz Ternik
Join Date: Apr 2009
Location: Maribor, Slovenia
Posts: 65
Rep Power: 8
ternik is on a distinguished road
Quote:
Originally Posted by braennstroem View Post
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
Hi Fabian,

thanks for the solver! But at the moment I am facing "conceptual" problems (see my previous post), i.e.:
  • how to create a mesh with "internal" region (ventilator)
  • how to model additional explicit source term in momentum equation (pressure drop caused by ventilator)
  • how to model explicit source term in equation for contaminant (at the first approach I would like to model it with scalar equation - it can be used as a tracer for contaminant concentration)
I think that last two "problems" can be resolved with "timeActivatedExplicitSource.C", but (again) my lack of experience with OpenFoam is responsible for my "cry for help" , while for resolving the first problem I do not have any idea at the moment !

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.
ternik is offline   Reply With Quote

Old   October 25, 2009, 16:46
Default
  #4
Senior Member
 
Fabian Braennstroem
Join Date: Mar 2009
Posts: 407
Rep Power: 10
braennstroem is on a distinguished road
Hi,

you should take a look at the solver. The definition of a volume source region is done using dictionaries see attached case.

Fabian
Attached Files
File Type: zip hotRoomHRR.zip (11.8 KB, 55 views)
braennstroem is offline   Reply With Quote

Old   October 25, 2009, 21:39
Default
  #5
New Member
 
Kurt Pudniks
Join Date: Sep 2009
Location: Australia
Posts: 6
Rep Power: 7
skinduptruk is on a distinguished road
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...?
skinduptruk is offline   Reply With Quote

Old   October 26, 2009, 02:40
Default
  #6
Member
 
Primoz Ternik
Join Date: Apr 2009
Location: Maribor, Slovenia
Posts: 65
Rep Power: 8
ternik is on a distinguished road
Quote:
Originally Posted by braennstroem View Post
Hi,

you should take a look at the solver. The definition of a volume source region is done using dictionaries see attached case.

Fabian
Fabian,

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.
ternik is offline   Reply With Quote

Old   October 26, 2009, 02:47
Default
  #7
Member
 
Primoz Ternik
Join Date: Apr 2009
Location: Maribor, Slovenia
Posts: 65
Rep Power: 8
ternik is on a distinguished road
Quote:
Originally Posted by skinduptruk View Post
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...?
Hi Kurt,

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!
ternik is offline   Reply With Quote

Old   October 27, 2009, 05:48
Default
  #8
Member
 
Primoz Ternik
Join Date: Apr 2009
Location: Maribor, Slovenia
Posts: 65
Rep Power: 8
ternik is on a distinguished road
Quote:
Originally Posted by braennstroem View Post
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
Hi Fabian,

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 OpenFoam-1.5 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.
Attached Files
File Type: gz ScalarSource.tar.gz (2.5 KB, 18 views)
ternik is offline   Reply With Quote

Old   November 23, 2009, 08:22
Default
  #9
New Member
 
Fabian Korn
Join Date: Mar 2009
Location: Heilbronn, Germany
Posts: 21
Rep Power: 8
fabian_korn is on a distinguished road
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
fabian_korn is offline   Reply With Quote

Old   November 26, 2009, 07:37
Default
  #10
Member
 
Primoz Ternik
Join Date: Apr 2009
Location: Maribor, Slovenia
Posts: 65
Rep Power: 8
ternik is on a distinguished road
Quote:
Originally Posted by fabian_korn View Post
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
Hi Fabian,

at the moment "this problem" is on stand-by!!! 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):
  • prescribe "smoke" concentration via "time&place" dependent source term (in scalar equation) - and my lack of OF experience is "guilty" for not resolving this approach!
When I will make any progress, I will keep you posted!

Cheers,
Primoz.
ternik is offline   Reply With Quote

Old   March 18, 2010, 09:28
Default
  #11
New Member
 
Aniko Rakai
Join Date: Oct 2009
Location: Budapest
Posts: 29
Rep Power: 7
ancsa is on a distinguished road
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.
ancsa is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Numercial Simulation on Contaminant Distribution Apple L S Chan Main CFD Forum 4 October 24, 2011 07:01
HOW TO PUT CONTAMINANT CONCENTRATION?????????? naus FLUENT 3 April 21, 2006 06:04
Ventilation Simulation & Experiment Data Luo Shengping FLUENT 2 November 30, 2000 05:00
Ventilation Simulation & Experiment Data Luo Shengping Main CFD Forum 2 November 29, 2000 11:29
The boundary condition of ventilation fans Luo Shengping Main CFD Forum 3 February 28, 2000 03:22


All times are GMT -4. The time now is 19:03.