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

Modelling an air filter

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

Reply
 
LinkBack Thread Tools Display Modes
Old   October 2, 2009, 02:57
Default Modelling an air filter
  #1
siw
Senior Member
 
Join Date: Jul 2009
Posts: 443
Rep Power: 13
siw will become famous soon enough
Hi,

I need to model air flow through a pipe and then into a radial filter and finally out through an exit pipe. Luckly, CFX has a tutorial for a porous domain modelling, which I shall run next. However, my filter is not a catalytic converter so the numerical data in the tutorial would be different to my case.

Does anyone have experience in modelling air filters, my past CFD work has always been on external aerodynamics, so some pointers would be useful. I doubt relative data will be available from the filter manufacturer - such as volume ratio as mentioned in the CFX Solver Theory guide.

Thanks,
siw is offline   Reply With Quote

Old   October 2, 2009, 07:39
Default
  #2
New Member
 
Join Date: Oct 2009
Posts: 11
Rep Power: 7
WalterW is on a distinguished road
I do have some experience with flat filter panels.

Usually, we measure the pressure drop of the cartridge in a rectangular or circular duct as a function of mass flow. It is then relatively safe to assume a uniform velocity distribution on the filter, allowing us to convert the (pressure-drop/mass flow) curve into a (pressure drop / mm filter height / velocity) curve, which usually looks like a 2nd grade polynom: Voilá, there are your linear and quadratic isotropic loss coefficients.

Something similar should work for radial filter cartridges, too.
WalterW is offline   Reply With Quote

Old   October 3, 2009, 05:18
Default
  #3
siw
Senior Member
 
Join Date: Jul 2009
Posts: 443
Rep Power: 13
siw will become famous soon enough
Great, thanks for the information. I have a few extra questions now that I have finished the Catalytic Converter tutorial.

Do you always set the Reference Pressure to the required value and keep the Relative Pressure zero? I found that for my external aerodynamics work this produced wrong answers and had to set the Ref. Press. to zero and the Rel. Press. to a value.

In the Porosity Settings Loss Model do you use the Superficial or the Tru Velocity Loss Velocity Type? The tutorial uses the Superficial but the guides don't say much about them.

Cheers.
siw is offline   Reply With Quote

Old   October 5, 2009, 07:54
Default
  #4
New Member
 
Join Date: Oct 2009
Posts: 11
Rep Power: 7
WalterW is on a distinguished road
Whoa.

Is the "Porous Domain" Domain type new to CFX 12?
I was taught to use subdomains to model a porous medium... and there is no option for superficial velocity and the like.
WalterW is offline   Reply With Quote

Old   October 5, 2009, 09:21
Default
  #5
Senior Member
 
ckleanth's Avatar
 
George
Join Date: Mar 2009
Location: Birmingham, UK
Posts: 257
Rep Power: 9
ckleanth is on a distinguished road
No the feature was available in v11. if you use a momentum loss in a fluid domain you have to use superficial velocity, for full porous domain model you can chose the velocity (superficial or true velocity) that your experimental values are based on.
__________________
Top 4 tips
1. Knowledge is everything and Ignorance is dangerous.
2. Understand your limitations and try to eliminate them.
3. Get yerself a bike and hoon the chuffer. You will soon learn why dogs like to hang their heads out the car window.
4. Please before asking any questions on how to run simulations in CFX, go though all the tutorials
ckleanth is offline   Reply With Quote

Old   September 13, 2011, 12:48
Default
  #6
New Member
 
Laura Jacobs
Join Date: Sep 2011
Posts: 2
Rep Power: 0
ljacobs12 is on a distinguished road
I don't know if this is an OK place to post my question because I am not sure what modeling an air filter is. To be honest, I don't know anything about air filters and I have really dumb question to prove it. Let me start out by saying that I am a girl and I know nothing about cars. For the past month my husband has been talking about how his car needs a new air filter and I'm going to surprise him by buying one and installing it in his truck! Step one was to start searching for where to buy them. I looked online and found this website that sells discount filters. I have no idea if these filters are the same kind of filters that go in vehicles. Can someone tell me if there is a difference between house air filters and car air filters? Does that place have the car kind? My second question is how to install them into the truck? Seriously, thank you so much for any help! Try to hurry with your answers, I want to have this done by this weekend!
ljacobs12 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
mass flow in is not equal to mass flow out saii CFX 2 September 18, 2009 08:07
air bubble is disappear increasing time using vof xujjun CFX 9 June 9, 2009 07:59
Air bearing modelling Dave Larkham CFX 1 October 19, 2008 19:10
Filter modelling Armando FLUENT 0 June 27, 2006 09:43
Air filter modeling Mohamad Tajali Main CFD Forum 1 December 5, 2005 11:16


All times are GMT -4. The time now is 21:11.