Hello,
I have hopefully a simple question about modeling the outlet conditions for a basic vacuum system involving an inlet and outlet. If the outlet is set close to the vacuum resource (vacuum pump), should the sticking factor be close to if not 1?
According to the guide, “A facet that has a sticking factor other than zero will absorb (pump away) particles”. This to me indicates a pump source that is downstream will need to be close to 1 as the particles are being pumped away.
Thank you
I don’t understand the term “vacuum resource” and “pump source”. Usually we refer to “source” as something creating gas particles, whereas a pump takes them out of the system.
In general, you would model a pump as a single facet, where the pump’s inlet is in real life.
Then you would need to set the pumping speed to equal that of the pump.
See second text field:
You need to set the gas type and temperature correctly for the sticking_factor ↔ pumping speed conversion.
If the pump is downstream (not at the modeled facet), you need a separate calculation to determine the effective (reduced) pumping speed at the facet.
Let me know what exactly you mean and maybe I can help further.
Apologies there, I was trying to indicate that the outlet is of a substantially lower pressure (or higher vacuum) than the inlet (source) where particles are being generated from.
Right now I have some conditions for the inlet (source) with an outgassing value, but am not sure how to define the conditions including sticking factor for the outlet which is of a much lower pressure.
Though after reviewing the tutorial video again, perhaps I have it modeled in reverse? Previously my source inlet of gas particles had desorption / outgassing values defined and maybe it should only be on the outlet where particles are being pumped away.
On the outlet there shouldn’t be outgassing, but only a sticking.
Inlet: set an outgassing with the desired value.
Outlet: set a sticking factor with the pump’s speed, if unknown, set a sticking=1.