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

buoyancy driven flows

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

Reply
 
LinkBack Thread Tools Display Modes
Old   June 7, 2007, 20:43
Default buoyancy driven flows
  #1
brian
Guest
 
Posts: n/a
My model is a vertical downflow model. I have a mass flow inlet at the top. In it the heat flux from the walls is great enough so natural convection occurs. I suspect the overall flow through the domain is constant, but there will be areas of recirculation near the hot walls.

My question is what outlet do I use? Fluent says not to use outflow for varying density flows. So I would suspect pressure outlet, but what does this impose?

I understand if I were to use pressure inlet and pressure outlet, by varying the DP in the domain, I'd vary the flowrate, but when i've already set the mass inlet flowrate, how does varying the pressure outlet affect the model? Thanks
  Reply With Quote

Old   June 8, 2007, 15:17
Default Re: buoyancy driven flows
  #2
Sujith
Guest
 
Posts: n/a
The flow rate will be constant as defined in inlet boundary condition. The outlet pressure will be used as a reference pressure to calculate the pressure in the remaining part of domain, using the dp obtained by solving the governing eqns.

if you vary the output pressure, you can see that input pressure also varies such that delta P will be constant.
  Reply With Quote

Old   June 20, 2007, 19:07
Default Re: buoyancy driven flows
  #3
red lemon
Guest
 
Posts: n/a
For buoyancy driven flows use presto or bfw pressure scheme with incomp-ideal-gas or ideal gas with gravity on. For v.low temp ranges you can use Boussinesq for density.
  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
continuity convergence in buoyancy driven flows brossofor FLUENT 0 March 29, 2011 04:31
Pressure correction in Buoyancy driven flows Aditya Main CFD Forum 0 March 8, 2007 07:36
Buoyancy Driven Flows Aditya Main CFD Forum 0 May 26, 2006 02:07
Buoyancy driven flows A. Guardo FLUENT 9 March 25, 2004 10:12
buoyancy driven flows anevin Main CFD Forum 2 January 1, 1999 00:56


All times are GMT -4. The time now is 14:21.