How to simulate valve with pressure BC?
 

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

Re: How to simulate valve with pressure BC?
 

Why don´t you change your pressure outlet to wall and backwards ?

Re: How to simulate valve with pressure BC?
 

Is it possible with UDF? I mean is it possible to periodicaly change type of BC for specified surface/face?

Re: How to simulate valve with pressure BC?
 

I didn´t work much with UDF´s. But I´m sure you can handle that with a journal file. The question is how often do you open and close?

Re: How to simulate valve with pressure BC?
 

About 100/sec. The size of the pipe is few cm in diameter and about 50cm length. Pressures are rather low.

Re: How to simulate valve with pressure BC?
 

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 it´s a long way.

Maybe someone else knows an alternative.

Re: How to simulate valve with pressure BC?
 

Dear Sir, Thanks for Your kind help! I'll try this solution today in few hours.

Luk

Re: How to simulate valve with pressure BC?
 

last chance for me to help you is tomorrow, then I´m 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

Re: How to simulate valve with pressure BC?
 

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