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

Help UDF to Boundary Conditions in Closed Loop Pipe

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 14, 2012, 07:58
Default Help UDF to Boundary Conditions in Closed Loop Pipe
  #1
New Member
 
blai
Join Date: Mar 2012
Posts: 8
Rep Power: 14
Blader is on a distinguished road
Hello,

I'm trying to simulate a closed loop pipe as the first figure. The fluid passes through an area where it is heated (wall-heated), and so on until reaching a stationary case where the fluid will have the same temperature as the hot wall (wall-heated).



I have found the problem that Fluent can not give a closed fluid velocity. So I designed an open loop where the exit temperature is equal to the inlet temperature, as shown in the figure below.



At first I tried to do with BC-Periodic function, but without results. For this reason and as a last solution, I want to do with a UDF. I want to take the temperature of the output and link it to the input, but just the temperature!

Someone who understands the issue of UDF can help me write, because I am new to the UDF.

Thanks in advance!

Blader.
Blader is offline   Reply With Quote

Old   May 14, 2012, 08:52
Default
  #2
Member
 
Daniel Tanner
Join Date: Apr 2009
Posts: 54
Rep Power: 17
Daniel Tanner is on a distinguished road
I think a periodic boundary condition would be best for this. Why did it fail for you?

How about simulating one quarter of the loop (i.e., it is a series of 4 right angle bends). This would be more representative as the circuit is symmetric in this way and you don't have to leave the gap. Then use the periodic boundary condition to ensure that the conditions of fluid leaving the bend are imposed on the fluid entering it.

For the periodic boundary condition you need to be careful to ensure that the mesh is the same on both inlet and outlet faces.
Daniel Tanner is offline   Reply With Quote

Old   May 14, 2012, 10:48
Default
  #3
New Member
 
blai
Join Date: Mar 2012
Posts: 8
Rep Power: 14
Blader is on a distinguished road
Hi,

To verify the functionality of the periodic boundary condition, I made the following fast simulation:

In the curved wall, apply a heat of 400 K. The temperature in periodic BC is 300K.

In the stationary case, the fluid temperature will be the same as wall heated, 400K,but as you see in the following figure, never reaches 400K !



That is why I ruled out the option of periodic boundary condition.

Someone can help me with the UDF?

Thanks
Blader is offline   Reply With Quote

Reply

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
NACA0012 geometry/design software needed Franny Main CFD Forum 13 July 7, 2007 16:57
DPM Boundary Conditions, UDF Juan FLUENT 1 November 11, 2005 15:37
Terrible Mistake In Fluid Dynamics History Abhi Main CFD Forum 12 July 8, 2002 10:11
Pipe Flow Boundary conditions Kunal Jain Main CFD Forum 0 September 4, 2001 21:52
Boundary Conditions Jan Ramboer Main CFD Forum 11 August 16, 1999 09:59


All times are GMT -4. The time now is 20:16.