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

Problem with modelling heat exchanger(fluid-solid-fluid-solid)

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

Like Tree4Likes

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 11, 2013, 16:36
Smile Problem with modelling heat exchanger(fluid-solid-fluid-solid)
  #1
New Member
 
saman poura
Join Date: Dec 2013
Posts: 13
Rep Power: 12
samanpoura is on a distinguished road
hi all
I am trying to model a simple heat exchanger,I want to see the temperature change between the two fluids and across the wall.
I create the geometry and mesh with the gambit,and Analys it with fluent,but flow temperetures,not changes,
T(inlet,cold water)=T(outlet,cold water)
T(inlet,hot water)=T(outlet,hot water)
i think my problem is boundery condition.
I upload gambit files
I hoped that some people on this forum would be able to help with a few issues I am having
please help me
thanks
http://www.4shared.com/file/PTHRtFi2/g-f.html (dbs format)
http://www.4shared.com/file/QZ2PFaij/g-f.html (mesh file)

Last edited by samanpoura; December 12, 2013 at 03:36.
samanpoura is offline   Reply With Quote

Old   December 16, 2013, 04:44
Default
  #2
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 26
RodriguezFatz will become famous soon enough
Can you post some pictures of the setup?
Yes, this sounds like some b.c. problem. What are you using? How did you mesh the solid body?
samanpoura likes this.
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   December 16, 2013, 05:08
Default
  #3
New Member
 
saman poura
Join Date: Dec 2013
Posts: 13
Rep Power: 12
samanpoura is on a distinguished road
i mesh model with gambit,and upload gambit and mesh file...
samanpoura is offline   Reply With Quote

Old   December 16, 2013, 05:10
Default
  #4
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 26
RodriguezFatz will become famous soon enough
The mesh file doesn't show your fluent settings. Also, I am at work and can't download files from mysterious places.
samanpoura likes this.
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   December 16, 2013, 05:27
Default
  #5
New Member
 
saman poura
Join Date: Dec 2013
Posts: 13
Rep Power: 12
samanpoura is on a distinguished road
upload all b.c?
if i upload cas and data file(fluent file),can u download them?
Attached Images
File Type: jpg cfd-1.jpg (27.4 KB, 23 views)
File Type: jpg cfd-2.JPG (34.5 KB, 21 views)
File Type: jpg cfd-3.JPG (52.0 KB, 19 views)
File Type: jpg cfd-4.JPG (32.6 KB, 17 views)
samanpoura is offline   Reply With Quote

Old   December 16, 2013, 06:38
Default
  #6
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 26
RodriguezFatz will become famous soon enough
Did you also set the material of the inner pipe to "solid, aluminium"? I can't see it on the picture, but you have some gridpoints in the solid (inner) part, right?
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   December 16, 2013, 07:02
Default
  #7
New Member
 
saman poura
Join Date: Dec 2013
Posts: 13
Rep Power: 12
samanpoura is on a distinguished road
I upload a new pic,
material of the iner pipe and outer pipe set to "solid, aluminium
iner flow inlet: v=0.5
T=370k
outer flow inlet: v=0.5
T=275
i mesh iner flow,outer flow,iner pipe and outer pipe
one question,what b.c set for the wall of iner pipe?(neighboring water)
Attached Images
File Type: jpg cgd5.jpg (45.9 KB, 14 views)
samanpoura is offline   Reply With Quote

Old   December 16, 2013, 07:09
Default
  #8
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 26
RodriguezFatz will become famous soon enough
You need to set both sides of the inner pipe to "coupled" for the thermal b.c.

Why is the inner fluid mesh so coarse?
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   December 16, 2013, 07:30
Default
  #9
New Member
 
saman poura
Join Date: Dec 2013
Posts: 13
Rep Power: 12
samanpoura is on a distinguished road
i improve the mesh and set both sides of the inner pipe to coupled
but the tempreture not change...
):
Attached Images
File Type: jpg cfd7.JPG (47.9 KB, 10 views)
samanpoura is offline   Reply With Quote

Old   December 16, 2013, 07:35
Default
  #10
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 26
RodriguezFatz will become famous soon enough
Did you also set the material property of the solid? I don't know what material is the default setting. Go to "Cell Zone Conditions" -> your solid body under "Zone" and see, if the "Type" is solid. Also click on "Edit..." and see, if the material is aluminium.
samanpoura likes this.
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   December 16, 2013, 07:39
Default
  #11
New Member
 
saman poura
Join Date: Dec 2013
Posts: 13
Rep Power: 12
samanpoura is on a distinguished road
yes,i do it
Attached Images
File Type: jpg cfd8.JPG (92.2 KB, 10 views)
samanpoura is offline   Reply With Quote

Old   December 16, 2013, 07:42
Default
  #12
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 26
RodriguezFatz will become famous soon enough
Hmmm... is the mesh conformal at all transitions fluid->solid->fluid?
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   December 16, 2013, 07:47
Default
  #13
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 26
RodriguezFatz will become famous soon enough
Also: Did you set both "wall:013" and "wall:013-shadow" to coupled, for both sides of the pipe? I don't know the meaning of these, but I just had a look at some old case and saw, that I did it there.
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   December 16, 2013, 07:48
Default
  #14
New Member
 
saman poura
Join Date: Dec 2013
Posts: 13
Rep Power: 12
samanpoura is on a distinguished road
yes
there is no conduction heat transfer acroas the iner pipe,but i dont know why..!!
samanpoura is offline   Reply With Quote

Old   December 16, 2013, 07:50
Default
  #15
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 26
RodriguezFatz will become famous soon enough
1) Yes to post #12 or #13?
2) Create a line perpendicular to the pipe and make an XY plot of temperature. Can you post it?
3) How is your y+ at all walls?
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   December 16, 2013, 07:58
Default
  #16
New Member
 
saman poura
Join Date: Dec 2013
Posts: 13
Rep Power: 12
samanpoura is on a distinguished road
i coupled both "wall:013" and "wall:013-shadow",but maybe i do it wrong
pleace say how can i couple walls...
Attached Images
File Type: jpg cfd9.JPG (33.5 KB, 6 views)
samanpoura is offline   Reply With Quote

Old   December 16, 2013, 08:01
Default
  #17
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 26
RodriguezFatz will become famous soon enough
wall:013 and wall:130-shadow are both the same wall. It is on one side of the inner cylinder. You also need to set the "coupled" b.c. to the other side of the inner wall.

Make an XY plot over a line. Not a contour plot.
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   December 16, 2013, 08:14
Default
  #18
New Member
 
saman poura
Join Date: Dec 2013
Posts: 13
Rep Power: 12
samanpoura is on a distinguished road
xy plot: center to outside
Attached Images
File Type: jpg cfd10.JPG (32.7 KB, 5 views)
samanpoura is offline   Reply With Quote

Old   December 16, 2013, 08:17
Default
  #19
Senior Member
 
RodriguezFatz's Avatar
 
Philipp
Join Date: Jun 2011
Location: Germany
Posts: 1,297
Rep Power: 26
RodriguezFatz will become famous soon enough
Do you have periodic boundary conditions in x-direction?
__________________
The skeleton ran out of shampoo in the shower.
RodriguezFatz is offline   Reply With Quote

Old   December 16, 2013, 08:20
Default
  #20
New Member
 
saman poura
Join Date: Dec 2013
Posts: 13
Rep Power: 12
samanpoura is on a distinguished road
no,i have'nt
i send u xy plot in y direction
samanpoura is offline   Reply With Quote

Reply

Tags
fluid-solid-fluid-solid, heat exchanger model, two-sided wall, wall thickness

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Modeling heat transfer fluid to solid Elvis1991 FLUENT 6 December 7, 2012 09:08
Heat Flux at Internal walls or Fluid Solid Interface Mahi CFX 3 October 1, 2012 02:18
goddamnit: how to set up heat transfer from fluid to solid macfly FLUENT 7 June 16, 2012 11:50
Enforce bounds error with heat loss boundary condition at solid walls Chander CFX 2 May 1, 2012 20:11
Conjugate Heat Transfer between fluid and solid Li Yang Main CFD Forum 8 March 27, 2004 11:05


All times are GMT -4. The time now is 08:55.