CFD Online URL
[Sponsors]
Home > Forums > FLUENT

Semi-transparent boundary conditions

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

Reply
 
LinkBack Thread Tools Display Modes
Old   April 16, 2014, 05:04
Default Semi-transparent boundary conditions
  #1
New Member
 
Joakim M. Johansen
Join Date: Apr 2013
Location: Denmark
Posts: 14
Rep Power: 3
jmjohansen is on a distinguished road
Dear community,

I am simulating a hot gas flow, low Re number flow through a square tube with quartz semi-transparent walls.

The gas flow inlet is 1600 K.
The average velocity is 1.9 m/s
The chimney is 55x55 mm cross section

I'm using the k-omega SST model with cell Re numbers close to the walls around 1. (I have a small but fast jet in the center of the chimney, making it non-laminar, but not affecting the flow to much at the wall)

I'm having trouble with the boundary conditions. The heat transport across the walls are essential to model correct, therefore my questions are fundamental:
- How do I estimate the radiation contribution in the best way through the semi-transparent wall (a few mm in thichness), I do not have any material specific information on this particular material.
- If I enable the mixed thermal boundary condition, the solution generates reversed flows in the outlet that will not dissappear?
- is it correctly understood, that if I enable the mixed contribution, define the external gas temperature, then it will autmatically simulate free convection and conduction on the external side without resolving it?
- I'm having doubts about how to interpret the radiation boundary condition panel?

Thanks in advance
jmjohansen is offline   Reply With Quote

Reply

Tags
conduction, heat transport, radiation, semi-transparent boundary

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
Question about heat transfer coefficient setting for CFX Anna Tian CFX 1 June 16, 2013 07:28
Impinging Jet Boundary Conditions Anindya Main CFD Forum 24 January 11, 2012 14:40
boundary conditions and mesh exporting vaina74 Open Source Meshers: Gmsh, Netgen, CGNS, ... 2 May 27, 2010 10:38
Trimmed cell and embedded refinement mesh conversion issues michele OpenFOAM Other Meshers: ICEM, Star, Ansys, Pointwise, GridPro, Ansa, ... 2 July 15, 2005 05:15
A problem about setting boundary conditions lyang Main CFD Forum 0 September 19, 1999 19:29


All times are GMT -4. The time now is 12:40.