CFD Online Logo CFD Online URL
Home > Forums > OpenFOAM

Gas mixture thermo properties

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

LinkBack Thread Tools Display Modes
Old   March 11, 2011, 22:45
Default Gas mixture thermo properties
New Member
Join Date: Aug 2010
Posts: 11
Rep Power: 7
guy_smiling is on a distinguished road

I have a gas nozzle with a backing pressure of ~1 atmosphere going into a chamber of low pressure. I can solve this for using a gas of only 1 type (oxygen, nitrogen etc) but when I try to use it for a gas of different types, I don't seem to get the answer I expect.

For example, in the Ladenburgjet case, the thermophysicalProperies file is
mixture air 1 28.96 1004.5 0 1.458e-06 110.4;
but if I try and use something like
mixture n2 0.8 28.01 1040 0 1.407e-6 103.5;
mixture o2 0.2 32.00 918.0 0 1.764e-6 139.9;
I don't get the same answer. Is there something else I need to be doing to define the mixture of the gas? I feel like it should be an simple solution. I'm using rhoCentralFoam to solve.

Changing the gases with a much more obvious mass difference still gives me an answer that i'm not expecting. I am using helium and O2, which has a substantial mass and maximum velocity difference. However, I'm still getting an answer that depends only on the O2 and not on the He at all. Even at ratios of 99.9% He and 0.1% O2, I get that the maximum velocity is only dependent on the O2. Once the O2 goes to zero, then I get a maximum velocity of helium.


Last edited by guy_smiling; March 17, 2011 at 17:57.
guy_smiling is offline   Reply With Quote


mixture of gases, rhocentralfoam, thermophysicalproperties

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
Calculation of the Governing Equations Mihail CFX 7 September 7, 2014 06:27
Constant velocity of the material Sas CFX 15 July 13, 2010 08:56
mass flow in is not equal to mass flow out saii CFX 2 September 18, 2009 08:07
Two-Phase Buoyant Flow Issue Miguel Baritto CFX 4 August 31, 2006 12:02
Gas pressure question Dan Moskal Main CFD Forum 0 October 24, 2002 22:02

All times are GMT -4. The time now is 20:42.