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

conjugate heat transfer boundary condition

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

Reply
 
LinkBack Thread Tools Display Modes
Old   June 11, 2010, 10:52
Default conjugate heat transfer boundary condition
  #1
New Member
 
souviktor
Join Date: Mar 2009
Posts: 11
Rep Power: 8
Souviktor is on a distinguished road
Hi all,

I am simulating a conjugate heat conduction problem in which a fluid is inside a glass tube having very large wall thickness.So I want to study the conduction through the wall as well as through the fluid.
So I have created an axisymmetric model in gambit.Now,the problem is setting of boundary condition for the internal surface of the glass tube.This surface is in contact with the fluid as well as the glass tube.

If I set it as wall what should be the thermal b.c at this wall?
If I set it as interface there is initialization error in fluent,

The heat flux is applied at the outer boundary of the tube.
If I apply wall b.c at the internal tube wall, then the heat does not conduct to the fluid as the default b.c in fluent is adiabatic wall b.c.
I am confused.can anyone please help?
Souviktor is offline   Reply With Quote

Old   June 11, 2010, 15:54
Default bc for conjugate
  #2
Senior Member
 
CFDtoy
Join Date: Mar 2009
Location: United States
Posts: 145
Blog Entries: 2
Rep Power: 8
CFDtoy is on a distinguished road
there is a bc called "coupled" bc - if there are 2 fluids on either side of the wall, you can use this condition and input wall thickness and material property (for resistance calculation) - this will serve to transmit data across different fluid regions.

fluent manual gives a very good explanation on how to do this.

Thanks,

/CFDtoy

Quote:
Originally Posted by Souviktor View Post
Hi all,

I am simulating a conjugate heat conduction problem in which a fluid is inside a glass tube having very large wall thickness.So I want to study the conduction through the wall as well as through the fluid.
So I have created an axisymmetric model in gambit.Now,the problem is setting of boundary condition for the internal surface of the glass tube.This surface is in contact with the fluid as well as the glass tube.

If I set it as wall what should be the thermal b.c at this wall?
If I set it as interface there is initialization error in fluent,

The heat flux is applied at the outer boundary of the tube.
If I apply wall b.c at the internal tube wall, then the heat does not conduct to the fluid as the default b.c in fluent is adiabatic wall b.c.
I am confused.can anyone please help?
__________________
CFDtoy
CFDtoy is offline   Reply With Quote

Old   July 3, 2010, 00:31
Default Coupled thermal Boundary Condition
  #3
New Member
 
Join Date: Aug 2009
Posts: 18
Rep Power: 8
chinc is on a distinguished road
I have created a 3 Dimensional two fluid zone (fluid-solid) with one of the two of the faces coupled to each of the fluid zone. When I read the mesh file, Fluent separate the coupled face into its "shadowed face". However, I did not manage to see the "couple" option under the wall zone during the setting of boundary condition. I am wondering what could be wrong with my setting.
Appreciate if you could provide some advice. Many thanks in advance.
chinc is offline   Reply With Quote

Old   July 7, 2010, 14:26
Default conjugate
  #4
Senior Member
 
CFDtoy
Join Date: Mar 2009
Location: United States
Posts: 145
Blog Entries: 2
Rep Power: 8
CFDtoy is on a distinguished road
did you check wall -> thermal boundary condition?

if you have a shadow wall..you will definitely see thermal coupled boundary condition. please check.


Quote:
Originally Posted by chinc View Post
I have created a 3 Dimensional two fluid zone (fluid-solid) with one of the two of the faces coupled to each of the fluid zone. When I read the mesh file, Fluent separate the coupled face into its "shadowed face". However, I did not manage to see the "couple" option under the wall zone during the setting of boundary condition. I am wondering what could be wrong with my setting.
Appreciate if you could provide some advice. Many thanks in advance.
__________________
CFDtoy
CFDtoy is offline   Reply With Quote

Old   January 5, 2012, 11:25
Default Hi
  #5
New Member
 
Join Date: Dec 2011
Posts: 11
Rep Power: 5
saksham.pachar is on a distinguished road
I have a flow condition.



Flow in a duct

Please guide

as I want to define the bottom of the fin at constant wall temp of 400 k.

but all the adjacent walls are also coming at 400K.

For a fin, In forced convection the temp should decrease , which is not happening.
saksham.pachar is offline   Reply With Quote

Old   March 13, 2014, 10:23
Default
  #6
Member
 
Join Date: Jan 2014
Location: Turkey
Posts: 36
Rep Power: 3
thermal energy is on a distinguished road
hello cfdtoy,


ı have a question about coupled boundry condition. ı need help. thank you. good work.

Should i activate coupled option for both wall and wall-shadow, for each side of the two-sided wall?
thermal energy is offline   Reply With Quote

Old   April 6, 2014, 17:34
Default Interface resistance units
  #7
New Member
 
Join Date: Nov 2013
Posts: 18
Rep Power: 3
magicalmarshmallow is on a distinguished road
Hi guys,

I'm a little confused about the units FLUENT requires. I am modelling conjugate heat transfer from a heated body, through an interface material to a fluid. Essentially I have a scenario of

Al block - Interface material - Cu pipe - Water
I have set up so that the interfaces between the materials are 'wall' and I have a 'wall-shadow' in all cases. Given water wets the surface of copper, I'm assume there is a negligible inter-facial resistance there. Application of a 0 m wall thickness gives a result which is nowhere near the experimental value.

So the Gap filler data sheet has a spec which reads

Thermal Resistance °C-Inē/W - 0.015

However, this unit doesn't seem to appear in FLUENT, so how do I convert this to "m", which is what FLUENT wants for the boundary layer thickness.

Does anyone have any experience of this. I'm guessing I'm missing a boat somewhere along the line

Thanks in advance
magicalmarshmallow is offline   Reply With Quote

Reply

Tags
boundary condition, conjugate heat transfer, interface, interior

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
CFX doesn't continue calculation... mactech001 CFX 6 November 15, 2009 22:25
Conjugate heat transfer and radiation modeling questions shankara.2 FLUENT 0 April 21, 2009 15:55
Conjugate heat transfer problem with porous media piko CD-adapco 1 April 17, 2009 15:41
How can I increase Heat Transfer at Domain Interf? B.Simon CFX 3 October 28, 2008 19:53
boundary condition for Heat Transfer sylvain Main CFD Forum 4 June 30, 2005 15:26


All times are GMT -4. The time now is 15:44.