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

question about free surface-multiphase simulation

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 30, 2011, 11:30
Default question about free surface-multiphase simulation
  #1
New Member
 
harry
Join Date: May 2009
Posts: 29
Rep Power: 8
rystokes is on a distinguished road
Hi all,

I'm running a multiphase simulation of air and water, both defined as continuous fluid, which are trapped in an enclosed chamber under rotation using cfx. I use inhomogeneous and standard free surface model , laminar condition.

In the fluid pair models, define free surface for the interphase transfer. And there is a drag force and coefficient option for the momentum transfer, and I just leave the default unchanged.

Chamber shape: block.

Initial condition: t=0, force the water takes 3/4 volume of the chamber, and air takes the rest 1/4 volume. And there is distinct interface between air and water.

Boundary condition: walls and symmetry ( no inlet and outlet)

Once t>0, the chamber is under rotation.

I'm interested in the interface change between air and water due to the rotation. There is still distinct interface between air and water during rotation, however, to my surprise, I found the volume of air is increased to be more than 1/4, and volume of water is reduced given the results I obtained.

Could anyone give me any suggestions please? Any problem with the model? Thanks.
rystokes is offline   Reply With Quote

Old   March 30, 2011, 19:36
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,656
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Please post some pictures of what you are seeing. Also why are you using the inhomogenous model? Do you expect foam or bubbles?
ghorrocks is offline   Reply With Quote

Old   March 31, 2011, 00:45
Default
  #3
New Member
 
harry
Join Date: May 2009
Posts: 29
Rep Power: 8
rystokes is on a distinguished road
Hi Ghorrocks,

Thanks for your reply. I just attached some pictures including the results and pre setting up, could you please take a look at them? Thanks.

Since in cfx, they define Inhomogeneous is the general case of multiphase flow, where each fluid has its own velocity field, and so on. I think air and water in my case should have their own velocity field, so I use the option. Thanks.
Attached Images
File Type: jpg fliud pair.jpg (39.0 KB, 19 views)
File Type: jpg multiphase.jpg (32.4 KB, 21 views)
File Type: jpg t=0.jpg (33.5 KB, 22 views)
File Type: jpg t=1s.jpg (35.4 KB, 19 views)
File Type: jpg t=1s (3d view).jpg (48.9 KB, 23 views)
rystokes is offline   Reply With Quote

Old   March 31, 2011, 06:37
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,656
Rep Power: 84
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
What is this trying to model? I still do not understand.

Why do you think air and water should have their own velocity field?
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
Help me for simulation free surface behest FLUENT 0 September 19, 2010 12:37
MULTIPHASE - FREE SURFACE & MIXTURE MODEL Aris FLUENT 3 April 28, 2009 11:46
Multiphase flow. Dispersed and free surface model Luis CFX 8 May 29, 2007 18:13
BC for free surface pilar FLUENT 3 January 14, 2004 08:36
turbulence simulation and free surface vineet Main CFD Forum 3 September 23, 2001 11:25


All times are GMT -4. The time now is 00:12.