CFD Online Logo CFD Online URL
Home > Forums > CFX

RGP file for CO2

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

LinkBack Thread Tools Display Modes
Old   November 16, 2006, 04:27
Default RGP file for CO2
Posts: n/a
I have to perform a calculation on a heat exchanger in which one of the fluid is CO2. I need a CFX RGP file covering the liquid, the gas and the supecritcal region of the phase state diagram. Is there anyone which has one already prepared or at least files covering pieces of the whole diagram?
  Reply With Quote

Old   November 16, 2006, 13:34
Default Re: RGP file for CO2
Posts: n/a
You could use the Redlich Kwong EOS, for which the solver builds the tables internally.
  Reply With Quote

Old   November 16, 2006, 16:50
Default Re: RGP file for CO2
Posts: n/a
So you are going to perform phase change modelling then as well?

What phase change model are you going to use?

The internal (mentioned by Phil) & presupplied tables are only appropriate for the equilibrium model.

You could pick an equation of state and create your own RGP table as well.
  Reply With Quote

Old   November 16, 2006, 17:38
Default Re: RGP file for CO2
Posts: n/a
I think that CFX is suitable only to superheat region, as stated in reference to RGP-file. (at least for version 5.7). Am I wrong?
  Reply With Quote

Old   November 17, 2006, 02:22
Default Re: RGP file for CO2
Posts: n/a
Certainly CFX can calculate flows of both liquids & vapours.

The doc for the RGP file certainly implies that perhaps you can only use it for superheated vapours.

However, if you carefully look at the file format you could use it for subcooled liquids as well. The file just gives material properties a f(T,p).

You just need to appropriately fill the "superheat" tables with subcooled liquid properties instead, for a liquid.

You make one material for the liquid with a liquid RGP file, one for the gas with a gas RGP file and throw the saturation properties into either, doesn't matter.

Since you can put multiple materials into a single RGP file a single file can hold liquid, vapour and saturation data.

One small caveat is that you need to add the following parameter:

RGP Liquid Properties = Subcooled

to the liquid material.
  Reply With Quote


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
swak4foam building problem GGerber OpenFOAM Installation 54 April 24, 2015 16:02
Installation of OpenFOAM-1.6 on Ubuntu 9.10 marval OpenFOAM Installation 2 March 17, 2010 09:33
Problem installing on Ubuntu 9.10 -> 'Cannot open : No such file or directory' mfiandor OpenFOAM Installation 2 January 25, 2010 10:50
Version 15 on Mac OS X gschaider OpenFOAM Installation 120 December 2, 2009 11:23
DxFoam reader update hjasak OpenFOAM Post-Processing 69 April 24, 2008 01:24

All times are GMT -4. The time now is 23:13.