CFD Online URL
[Sponsors]
Home > Forums > FLUENT

Enabling ideal gas for nitrogen

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

Reply
 
LinkBack Thread Tools Display Modes
Old   February 26, 2005, 22:49
Default Enabling ideal gas for nitrogen
  #1
manish
Guest
 
Posts: n/a
Hello everyone,

How do you enable ideal gas for nitrogen?

I have donwloaded nitrogen from the database, and I have specified it as ideal gas, and Sutherland's law for viscosity. The problem I am having is that when I run the simulation, the density is ALWAYS CONSTANT!

This will definitely give me a huge error in my results. HOPEFULLY, someone has the answers.

Thank you. -Manish
  Reply With Quote

Old   February 26, 2005, 22:57
Default Re: Enabling ideal gas for nitrogen
  #2
manish
Guest
 
Posts: n/a
With the same setup and if I enable air, i see a flucutation in density. I do not know if for diatomic gases if there should be a different setting. should i set the degree of freedom...it is at zero. hope someone can help me out. thanks.
  Reply With Quote

Old   February 27, 2005, 01:59
Default Re: Enabling ideal gas for nitrogen
  #3
Manoj Kumar
Guest
 
Posts: n/a
Goto Define/Boundary Conditions and open Fluid Panel corresponding to ur Fluid Zone and set 'Material Name' as nitrogen.

Try this ...
  Reply With Quote

Old   February 27, 2005, 02:02
Default Re: Enabling ideal gas for nitrogen
  #4
manish
Guest
 
Posts: n/a
Thank you! It definitely worked. I am just trying to get it to converge.

-manish
  Reply With Quote

Old   March 2, 2005, 05:56
Default Re: Enabling ideal gas for nitrogen
  #5
Melaku H.
Guest
 
Posts: n/a
Hi,

Yeah that is a little bug I guess. The ppl at Fluent need to fix it...one doesn't have to set matrial properties twice! Pls make sure the operating pressure is ok too. If you have a closed domain you probably need to activate floating operating pressure inorder to get a reasonable convergence.

good luck

Melaku H.
  Reply With Quote

Old   March 2, 2005, 09:04
Default Re: Enabling ideal gas for nitrogen
  #6
manish
Guest
 
Posts: n/a
I just have a jet impinging on a plate...do I need to have a floating operating pressure for this. I set my operating pressure as the standard chamber atmosphere, and I set my boundary conditions accordingly. Is this okay? I was told it was.

hope to hear from someone soon. thanks.

-manish
  Reply With Quote

Old   March 2, 2005, 12:46
Default Re: Enabling ideal gas for nitrogen
  #7
Melaku H.
Guest
 
Posts: n/a
Hi,

My answer would be a NO! It appears to me that you have external flow at hand and if there is no change in the level of absolute pressure(not guage) and the simulation is steady....I don't think any reason to have floating operating pressure. It is used when you usually have a closed domain or open at one end only...e.g filling of a pressure tank.

rgds

Melaku H
  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
Calculation of the Governing Equations Mihail CFX 7 September 7, 2014 07:27
Constant velocity of the material Sas CFX 15 July 13, 2010 09:56
mass flow in is not equal to mass flow out saii CFX 2 September 18, 2009 09:07
Two-Phase Buoyant Flow Issue Miguel Baritto CFX 4 August 31, 2006 13:02
Gas pressure question Dan Moskal Main CFD Forum 0 October 24, 2002 23:02


All times are GMT -4. The time now is 17:37.