Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

vacuum pump: differenct BCs

Please login with a confirmed email address before reporting spam

Hello there!

When building a CFD-model, the following BC seem to work best (according to my tests and research):
Inlet: velocity Outlet: rel. pressure

My problem: I`d like to simulate a stationary air flow caused by a vacuum pump. With a given max. vacuum (Pa) and max. flow rate (m³/s) of the vacuum pump, the max. average velocity at the inlet/outlet is also given. Both of the following BCs result in a convergent, yet different, solution:
1) Inlet: max. given velocity ; outlet: p = 0 Pa
2) Inlet: max. given velocity ; outlet: p = - max. vacuum (Pa)

Am I correct by saying: 2) is the right way to go for a vacuum pump problem?

Thanks in advance!

1 Reply Last Post 21 ago 2017, 05:09 GMT-4

Please login with a confirmed email address before reporting spam

Posted: 7 years ago 21 ago 2017, 05:09 GMT-4
Hi,

In case 1) as I have been informed by COMSOL representative, if you set up 0 it means that it gives you the pressure that you had in Initial values, so until it isn't the right pumping pressure for vacuum pump you have to type the other value.
Hi, In case 1) as I have been informed by COMSOL representative, if you set up 0 it means that it gives you the pressure that you had in Initial values, so until it isn't the right pumping pressure for vacuum pump you have to type the other value.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.