# Heat transfer between two closed cavities with natural convection

 User Name Remember Me Password
 Register Blogs Members List Search Today's Posts Mark Forums Read

 LinkBack Thread Tools Search this Thread Display Modes
October 28, 2014, 05:39
Heat transfer between two closed cavities with natural convection
#1
New Member

Cezary
Join Date: Jul 2014
Posts: 5
Rep Power: 11
Hi,

I am modelling a 2D axisymmetric heat transfer between two closed cavities. One is filled with air, another with helium. Heat source is placed at the axis. BC is a constant temperature at the wall of the outer domain - air. Heat is being transferred through the natural convection (no pressure BC, no inlet or outlet). I am using Fluent software. My question is: Is it possible to determine different operating conditions for those domains, as Fluent requires operating density and pressure for natural convection calculations. Helium and air are under different pressure and of course have different densities. Had anyone solve such case?

I am working also on 3D version of this problem, however calculations are quite time consuming, so I use 2D for preliminary settings.

In the picture green is helium, blue is air.

I would appreciate any possible help with this case.

Does using 0 for operating density solve the problem? Is it obligatory for solver to use operating density for natural convection?

Regards,
Czarulla
Attached Images
 1312.jpg (51.6 KB, 25 views)

Last edited by Czarulla; November 4, 2014 at 09:40. Reason: new idea

 November 19, 2014, 07:18 #2 New Member   Cezary Join Date: Jul 2014 Posts: 5 Rep Power: 11 For other users, I have solved the problem. There is no possibility of setting two different operating pressure and densities. However, my fault was using incompressible ideal gas model. Now I use ideal gas model and set operating density to 0, operating pressure equal pressure in one domain. When both domains have different pressure, you need to patch appropriate pressure in both domains. Remember that ideal gas model is using pressure in cell + operating pressure for calculating density. What is more, Full Bouyancy option have to be picked. With that option you can simulate your transient with natural convection.

 August 5, 2020, 12:36 #3 Member   Himanshu Join Date: Jan 2017 Posts: 34 Rep Power: 9 Hello sir, Why is the reason of setting operating density to 0 for ideal gas?

 Thread Tools Search this Thread Search this Thread: Advanced Search Display Modes Linear Mode

 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 OffTrackbacks are Off Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post srinivasa FLUENT 21 November 11, 2016 06:08 ninjakid FLUENT 0 July 3, 2012 12:03 mehrdadeng CFX 10 February 25, 2011 05:25 Sidy FLUENT 1 October 18, 2008 03:27 max91 CFX 1 July 29, 2008 20:28

All times are GMT -4. The time now is 18:22.

 Contact Us - CFD Online - Privacy Statement - Top