Is it possible to simulate opening and closing of gate valve in UHV chamber. The effect of movement of gate valve on the pressure readings.
Hello Sunil,
sounds like you are looking to setup a time-dependent simulation.
Take a look at this document (from p6):
You can define a parameter for time-dependent outgassing, which you can then use for the inlet of the chamber.
Hi pascal,
Thanks. yes it is indeed a time dependent simulation. But I need to see the sudden change if any in the pressure reading, especially if the gate valve has a very small leak.
Dear Sunil,
A gate valve’s opening and closing can be simulated with the opacity parameter, which can also be time-dependent.
An example is in this video:
https://cernbox.cern.ch/index.php/s/70G6MJnTioWxaDL
Time-dependent parameter basics:
https://molflow.web.cern.ch/node/214
Youtube:
Good luck, Marton
Hello Sunil:
I did something like this a few years ago, when an accelerator here at CERN needed to use fast-acting valves from VAT, that can close in ~ 20 ms (not gate-valves, they have a circular plate that rotates by 90 deg, in fact they are not leak tight, they simply shut off the direct line of sight of a fast molecular jet eventually been created by a leak or a loss of vacuum).
Unfortunately I can’t find the file now… if I’ll do it later I’ll share it with you… but I do remember how I did it. I set up a time-dependent simulation and the moving surfaces where simulated “in steps”, i.e. creating a series of facets corresponding to the moving part of the valve (the dish/plate with some thickness typically, you don’t need to model the internal shafts, unless you want to…). The trick is to set up the opacity of the groups of facets representing the said moveable parts so that at the beginning the solid one is the one representing the valve position (open or closed, depending on what you want to do) and then after a short time (shorter that a representative time for molecular movements, depends on temp and mass of the gas, of course) the parameter file changes those facets’ opacity to zero (i.e. transparent) and sets to 1 (opaque, solid) the facets representing the valve’s plate in a slightly different position… and you repeat the process. It may be tedious, but it work… and I can’t see any other way to do it in Molflow+ as it is now… sorry!
I may be willing to help you, in case you need assistance, but in that case better to e-mail me directly rather than posting many messages here.