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

How to simulate valve with pressure BC?

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

Reply
 
LinkBack Thread Tools Display Modes
Old   June 20, 2006, 01:27
Default How to simulate valve with pressure BC?
  #1
Luk
Guest
 
Posts: n/a
Hi all, I have following problem. The geometry is very simple: air enters the pipe from one side under pressure. On the other side there is valve: the valve could be in one of two positions: "closed" where no flow is possible (pipe closed from one side) and "opened" where sucking occurs through the valve. The valve opens and closes periodicaly. I am using UDF to represent changes of the valve state in time but I dont know how to simulated closed valve with pressure BC.

Any ideas? Luk
  Reply With Quote

Old   June 20, 2006, 02:31
Default Re: How to simulate valve with pressure BC?
  #2
Gernot
Guest
 
Posts: n/a
Why donīt you change your pressure outlet to wall and backwards ?
  Reply With Quote

Old   June 20, 2006, 03:46
Default Re: How to simulate valve with pressure BC?
  #3
Luk
Guest
 
Posts: n/a
Is it possible with UDF? I mean is it possible to periodicaly change type of BC for specified surface/face?
  Reply With Quote

Old   June 20, 2006, 04:47
Default Re: How to simulate valve with pressure BC?
  #4
Gernot
Guest
 
Posts: n/a
I didnīt work much with UDFīs. But Iīm sure you can handle that with a journal file. The question is how often do you open and close?
  Reply With Quote

Old   June 20, 2006, 06:12
Default Re: How to simulate valve with pressure BC?
  #5
Luk
Guest
 
Posts: n/a
About 100/sec. The size of the pipe is few cm in diameter and about 50cm length. Pressures are rather low.

  Reply With Quote

Old   June 20, 2006, 06:46
Default Re: How to simulate valve with pressure BC?
  #6
Gernot
Guest
 
Posts: n/a
O.K., i tried some things. To change the boundary condition with a journal file is possible. To start the journal file with an execute-comand works too. So there is a posibility to automate the whole thing but itīs a long way.

Maybe someone else knows an alternative.

  Reply With Quote

Old   June 20, 2006, 07:07
Default Re: How to simulate valve with pressure BC?
  #7
Luk
Guest
 
Posts: n/a
Dear Sir, Thanks for Your kind help! I'll try this solution today in few hours.

Luk
  Reply With Quote

Old   June 20, 2006, 07:25
Default Re: How to simulate valve with pressure BC?
  #8
Gernot
Guest
 
Posts: n/a
last chance for me to help you is tomorrow, then Iīm on holiday for 2 weeks - Jippie!!!!

The execute comand to start the journal is easy :

file read-journal nameofjournal

the journal comands to switch from wall to pressure outlet :

define boundary-condition modify-zones zone-type ( ID number of your face you want to switch ) pressure-outlet ( or wall when you switch back )

but be careful the settings of your pressure outlet are set to the default values. you can change them with :

define boundary-condition pressure-outlet

good luck
  Reply With Quote

Old   June 20, 2006, 08:06
Default Re: How to simulate valve with pressure BC?
  #9
Luk
Guest
 
Posts: n/a
I wish Your nice holydays! Could You be so kind and send me email for further contact: my address is Lukasz.Czopyk@ifj.edu.pl. I promise not to disturb Your free time anyway.

Luk
  Reply With Quote

Reply

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
"Pressure Inlet" Boundary Setup Wijaya FLUENT 13 April 11, 2013 08:50
how to simulate pressure variation wrt time at outlet gyanesh FLUENT 4 April 21, 2011 03:42
How to simulate valve using pressure BC?? Luk_Fiz CFX 4 August 16, 2010 18:27
Does star cd takes reference pressure? monica CD-adapco 1 April 19, 2007 11:26
Neumann pressure BC and velocity field Antech Main CFD Forum 0 April 25, 2006 02:15


All times are GMT -4. The time now is 03:00.