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

Helium3 in low Temp -real gas

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

Reply
 
LinkBack Thread Tools Display Modes
Old   August 27, 2010, 04:50
Default Helium3 in low Temp -real gas
  #1
New Member
 
anton.gardi
Join Date: Aug 2010
Posts: 21
Rep Power: 6
gardian is on a distinguished road
Hello
I m running some simulations with He3 gas. it is a long tube (10 m) A=14.5 cm^2 filled with this gas. the temp of this tube is 2K BUT at the both ends of this tube I apply 70K . The tube is closed . when i run simulations with temp of the ends=20K and pressure inside =0.085 bar i had really good results. but now running the model with new boundary conditions (70K at the ends, 2K in the tube -15mbar ) the results are not so good. I m using the k-e turbulence model.
I used as heat transfer the Thermal energy and things get better. I noticed that at the ends the Reynolds number is very low. ~100. something is wrong.
It looks like there is very little gas at the ends and goes really fast ~100m/s.
any suggestion if I was clear enough? i tried also other turbulence models for low Reynolds number (sst etc ) but with no success.
thank you
gardian is offline   Reply With Quote

Old   August 27, 2010, 06:38
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,831
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
What is driving the flow?
ghorrocks is offline   Reply With Quote

Old   August 27, 2010, 06:59
Default He3
  #3
New Member
 
anton.gardi
Join Date: Aug 2010
Posts: 21
Rep Power: 6
gardian is on a distinguished road
In the 10m tube there is always a heat load of 2K while at the ends a thermal load of 70 K is applied. so I think the answer to your question if i m not wrong is the buoyancy and the convection.
gardian is offline   Reply With Quote

Old   August 28, 2010, 06:50
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,831
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
This is so far out of my area of expertise that I have no idea what to expect from this flow. What is the Rayliegh number? Is the flow really turbulent?

Do you want steady state or transient results?
ghorrocks 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
Constant velocity of the material Sas CFX 15 July 13, 2010 08:56
enum MASOUD Fluent UDF and Scheme Programming 0 June 5, 2010 00:49
mass flow in is not equal to mass flow out saii CFX 2 September 18, 2009 08:07
Too low Flame temp for Spe.Tran. Produce Gas Comb Manoj Prasad FLUENT 4 November 22, 2005 02:09
Multicomponent fluid Andrea CFX 2 October 11, 2004 05:12


All times are GMT -4. The time now is 21:20.