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

Air density variation

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

Reply
 
LinkBack Thread Tools Display Modes
Old   November 15, 2014, 14:46
Unhappy Air density variation
  #1
Senior Member
 
hmasenger's Avatar
 
hamed
Join Date: Apr 2009
Posts: 148
Rep Power: 8
hmasenger is on a distinguished road
hi dear friends.
i am modeling an air intercooler that cool's down compressed air.so air density changes(increases) while passing throw the intercooler and i need to monitor density and temperature variation.
the problem is that i cant define air proper density at inlet BC.

the air pressure is 2 bars and the temperature is equal to 146 deg of centigrade and a mas flow of 0.26kg/sec at inlet.

how can i set the pressure and mass flow together at inlet Bc?how should i chenge the material properties to have the right air density at pressure and temperature variation?
the velocity is about 3 to 12 m/sec and is far far away from speed of sound.i dont know if i should model a compressible flow?i know air can be assumes as ideal gas in my situation but how can i define the right density at inlet and monitor its variation throw the intercooler?
hmasenger is offline   Reply With Quote

Old   November 16, 2014, 05:13
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,651
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Quote:
how can i set the pressure and mass flow together at inlet Bc?
You can't. It is mathematically over specifying the flow so it is not possible. Instead put the mass flow rate boundary on the outlet and the pressure condition at the inlet. Easy fixed.

You will need to use the total energy model so the temperature can affect the density. (Just read the doco and it suggests a Thermal Energy model would also do it but I thought that was a constant density model)
ghorrocks is offline   Reply With Quote

Old   November 16, 2014, 06:28
Default
  #3
Senior Member
 
hmasenger's Avatar
 
hamed
Join Date: Apr 2009
Posts: 148
Rep Power: 8
hmasenger is on a distinguished road
Tnx gelenn .I really appreciate your guides
hmasenger 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
Current density visualisation (PEM fuel cell add-on module) pchoopanya FLUENT 4 March 24, 2015 07:58
Simulation of air flow in a chamber Issa CFX 3 November 23, 2009 18:16
gas(same density with air) dispersion in the air ? panda60 OpenFOAM 0 November 5, 2009 06:42
mass flow in is not equal to mass flow out saii CFX 2 September 18, 2009 08:07
Where can I find air density Matthew Bliss Main CFD Forum 2 December 9, 1998 04:28


All times are GMT -4. The time now is 01:21.