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

moist air density

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 7, 2001, 23:53
Default moist air density
  #1
rafat
Guest
 
Posts: n/a
Hi, I am trying to simulate a natural-draft wet cooling tower performance. I want to use a single phase simulation using Fluent 5.4 . I am trying to define the density of the moist air at the inelt. my problem is the interaction between the air and water "theoritically". I wonder if anyone has come by such a problem to help me.

I mean what sort of function should I use to express the change in the air density.

thanks for your help in advance.
  Reply With Quote

Old   June 8, 2001, 05:03
Default Re: moist air density
  #2
Bart Prast
Guest
 
Posts: n/a
If you do not include phase transition (condensation of water) you can do this by assuming a mixture of 2 ideal gases (air/water vapour): P = Pvapour + Pair with Pvapour the partial vapour pressure (saturation ratio * saturated vapour pressure)
  Reply With Quote

Old   June 8, 2001, 05:37
Default Re: moist air density
  #3
rafat
Guest
 
Posts: n/a
This has opend the door to another variable Pvabour. I am affraid I do not have enogh skill to play around with fluent. I am trying to find the way of mixing two fluid together.
  Reply With Quote

Old   June 8, 2001, 05:47
Default Re: moist air density
  #4
Bart Prast
Guest
 
Posts: n/a
If you need the density of moist air specifically (as opposed to dry air), you need the properties of the water vapour. You can also do this in terms of mass fractions.
  Reply With Quote

Old   June 12, 2001, 12:49
Default Re: moist air density
  #5
Sergei Zhubrin
Guest
 
Posts: n/a
Check out PHOENICS User Support pages at http://www.simuserve.com/cfd-shop/support.htm.

Under 'On-line CFD calculators' you will find one called 'Air-water saturation' for the estimation of some air-water saturation data .

Give it a try and look at what it says re underlying methods.

Regards

Sergei Zhubrin
  Reply With Quote

Old   June 13, 2001, 22:36
Default Re: moist air density
  #6
rafat
Guest
 
Posts: n/a
Thank you for this, I tried to run it but it send me an error in the page. I will try it later on. thnk you again.
  Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
A problem about density in liquid air definition alloveyou CFX 2 June 14, 2012 15:20
air bubble is disappear increasing time using vof xujjun CFX 9 June 9, 2009 08:59
Hurry!How to simulate mass transfer of moist air? YAng bin FLUENT 0 January 11, 2005 22:15
Hurry!How to simulate mass transfer of moist air? Yang Bin FLUENT 0 January 9, 2005 07:57
Warning 097- AB Siemens 6 November 15, 2004 05:41


All times are GMT -4. The time now is 17:40.