Modeling sudden flow in Vacuum chamber

Sandilya Garimella

I am interested in modeling the following scenario. Can anyone give me insight into how to model it?

There is a vacuum chamber which is being pumped down by a pump. There is an inlet to the chamber to send in gas phase chemicals. The inlet is operated by a valve which opens for 20 milliseconds to sample in air.

During sampling, the pressure of chamber rises due to exposure to atmospheric pressure and after closing of the valve, the pressure falls back

I am interested in modeling this cycle.

I want to know, how to model the pump boundary condition in fluent and maintain a low pressure in the flow domain

Also after the initial sampling time, the valve opening BC should represent a wall through the rest of the cycle.

Can anyone tell me a general idea how to possibly acheive thsi?

Thank you