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

Periodic Linear BC

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 20, 2016, 09:30
Default Periodic Linear BC
  #1
Member
 
Join Date: Sep 2016
Posts: 43
Rep Power: 10
diggee is on a distinguished road
Hello. I am modeling a corrugated plate heat exchanger. This is the isometric view of the complete 3 plate assembly. The red and blue region are the hot and cold channel, respectively with the three plates in-between them. This is better illustrated in this exploded view.

I want to impose conditions in fluent such that there is a cold channel above the topmost plate and a hot channel below the bottommost plate and so on effectively making it an assembly of infinite plates and channels. The sequence would look like '...-C-P-H-P-C-P-H-P-C-....' where C is cold channel, P is plate and H is hot channel. Can anyone please suggest as to how I should go about this?


Or I will be more then happy if someone can suggest a way that will make fluent treat the top most surface (top surface of the 1st plate) equivalent to the surface of the plate in contact with the cold channel (top surface of the 3rd plate) and similarly the bottom surface of the 3rd plate equivalent to the bottom surface of the first plate? By equivalent I mean that the temperature at those plate surfaces should be the same.



PS - I am sorry if the title is misleading, I do not know how to word this better.
diggee is offline   Reply With Quote

Old   September 20, 2016, 17:16
Default
  #2
Senior Member
 
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,743
Rep Power: 66
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
It looks like you just need to use a periodic boundary condition.
The TUI command is:
mesh/modify-zones> make-periodic

then follow the prompts
LuckyTran is offline   Reply With Quote

Old   September 20, 2016, 17:26
Default
  #3
Member
 
Join Date: Sep 2016
Posts: 43
Rep Power: 10
diggee is on a distinguished road
Yes I already did try that but it gives the following error

Warning: Number of elements does not match between zone 6 and 10.
Error: Failed to make zones periodic.
Error Object: #f

What does that mean?
diggee is offline   Reply With Quote

Old   September 20, 2016, 22:31
Default
  #4
Senior Member
 
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,743
Rep Power: 66
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
You need to make sure the mesh is matching (conformal) on both surfaces before you can make them periodic.
LuckyTran is offline   Reply With Quote

Old   September 21, 2016, 01:50
Default
  #5
Senior Member
 
Paritosh Vasava
Join Date: Oct 2012
Location: Lappeenranta, Finland
Posts: 732
Rep Power: 23
vasava will become famous soon enough
You can create an interface between both the surfaces and while doing so, select 'periodic'. Worth a try!

If it dosent then as LuckyTran suggested, you need matching/conformal mesh on both the surfaces.

Last edited by vasava; September 21, 2016 at 01:50. Reason: typo
vasava is offline   Reply With Quote

Old   September 21, 2016, 06:00
Default
  #6
Member
 
Join Date: Sep 2016
Posts: 43
Rep Power: 10
diggee is on a distinguished road
Yes I know but the problem in trying to do that is that I have already combined all the parts into one body to get conformal meshing throughout and to avoid mesh interfaces. But since the top surface of the 3rd plate has the cold channel on top of it, its topology is now different from the top surface of the 1st plate which results in a non identical mesh on these two surfaces. I hope the two images below illustrate this better.

http://imgur.com/XRV5Qaz

http://imgur.com/3YFcQXC
diggee is offline   Reply With Quote

Old   September 21, 2016, 16:43
Default
  #7
Member
 
Join Date: Sep 2016
Posts: 43
Rep Power: 10
diggee is on a distinguished road
Quote:
Originally Posted by LuckyTran View Post
You need to make sure the mesh is matching (conformal) on both surfaces before you can make them periodic.
Hey, I changed my setup slightly so that I could do this. I now have conformal meshes on the topmost and bottom most surface. I did make them periodic from the TUI and it was a success! Fluent went on to delete one of these surfaces then as it is supposed to do with periodic faces, I guess.

The problem now is that what do I give as input to the periodic boundary condition? There is certainly no mass flow as I have made the two solid plates periodic. Since there is no fluid flow through the plates but only conduction, I do not think that I can give a value for pressure gradient too. What about the values for the direction?
diggee is offline   Reply With Quote

Old   December 10, 2017, 09:38
Default
  #8
New Member
 
Caner
Join Date: Jan 2010
Posts: 8
Rep Power: 16
Caner is on a distinguished road
Hello diggee

Did you solve your problem about defining an input for periodic boundary condition?
Caner is offline   Reply With Quote

Reply

Tags
boundary condition, linear, periodic

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
2nd Order Convergence Problem for 3D Airfoil turkmengokce OpenFOAM Running, Solving & CFD 1 September 10, 2015 07:20
A turbulent test case for rhoCentralFoam immortality OpenFOAM Running, Solving & CFD 13 April 20, 2014 06:32
suitable boundary condition for scavenging process? immortality OpenFOAM Running, Solving & CFD 3 January 25, 2013 19:10
how to modify fvScheme to converge? immortality OpenFOAM Running, Solving & CFD 15 January 16, 2013 13:06
solution diverges when linear upwind interpolation scheme is used subash OpenFOAM 0 May 29, 2010 01:23


All times are GMT -4. The time now is 04:20.