CFD Online Logo CFD Online URL
Home > Forums > FLUENT

Conduction in rotating mesh

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

LinkBack Thread Tools Display Modes
Old   May 4, 2007, 08:13
Default Conduction in rotating mesh
Niels Linnemann
Posts: n/a
Hello I an simulating heat transfer in a rotary regenerator used for preheating combusting air. The preheater can be considered a big circular disk with many plates in the radial direction which draws heat by convection in the hot side and releases heat in the cold side.

I have modeled the preheater as a porous zone with a UDF file for specifying heat transfer from and to the "non" existing solid in the porous zone.

The problem is that in this way I have to specify a fixed wall temperature which isn't the case since it is rotating so there will be a temperature gradient in radial and rotational direction.

In order to update the temperature profile I use the source-terms from the porous case in another case with a pure solid conduction problem with modification to the conduction term in order to simulate the porosity.

Both cases are rotating with 0.088rad/s, but when i simulate the solid case I get +5000K on one of the sides and -1K on the other side of the centerline with temperature gradient parallel to the centerline (they should be angeled). In then thought well maybe the energy balance is not fulfilled since I use guessed values for the surface temperature in the first run. Then I tried making a simple model with source terms that are positive above the centerline and negative below the centerline, this way the source term and volume exactly match so energy balance is fine. BUT the temperature profiles are still parallel to the centerline which shouldn't be the case when the solid is rotating. Increasing or decreasing the rotational velocity does not change anything although you see a change in the porous case.

I have not found anything in the manual or the web that addresses this kind of behavior.

The solid case is a pure conduction (circular disk) problem no flow and adiabatic walls, with an UDF file mapping the source terms to the geometry.

The Porous case is a pure flow problem with an UDF file to simulate convection to a non existing solid.

I have tried updating the surface temperature directly in the porous case but in this way the conduction is not simulated.

If anyone have a solution or another approach that could be used please let me know.
  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
Rotating mesh Jesper CFX 14 April 27, 2012 17:57
problem with rotating mesh viet CFX 5 March 10, 2007 00:16
rotating mesh manohar FLUENT 3 July 6, 2005 11:52
Multiple rotating frame VS dynamic mesh Jen FLUENT 3 July 2, 2005 06:31
How to control Minximum mesh space? hung FLUENT 7 April 18, 2005 09:38

All times are GMT -4. The time now is 02:36.