hello,
I have a problem with my simulation. I get some inputs: a tube, one side has an exhaust pump of 700L/s, another side has a gas inlet pump of about 3m3/h (~~0.83L/s). how can I handle the gas inlet side? Can I use the data 699.2L/s=700-0.83 for particles out? Or use Particles in： uniform, outgassing (mbar*L/s)， 0.0083=0.83L/s *0.01mbar? Or other method? My target is over 1E-7 mbar.
Sorry for the late reply, many of us are at a conference abroad.
If let’s say left side is a gas in of 0.83l/s at 0.01mbar, and right side is 700l/s out, then:
left side: Cosine desorption of 0.0083mbar.l/s, no sticking
right side: no desorption, sticking equivalent to 700l/s
Thanks for your reply.
sorry, I made a wrong input of 0.01mbar（of environment pressure）. Actually, I don’t have the gas in pressure data, only pump speed data of 0.83L/s.
Can I use the data of environment pressure 0.1Mpa == 1010mbar on gas in side? Such as 1010mbar* 0.83L/s？ if so, the target of 1E-7mbar can’t be realized. It seems too much gas in.
Or can I use a target vacuum pressure 1E-7mbar on gas in side? such as1E-7mbar* 0.83L/s？
Maybe the data of gas in V= 0.83l/s is adjustable, I need to change it to meet the target vacuum pressure over1E-7mbar? So my input maybe is"1E-7mbar* V " or “which pressure *V” ?
Sorry, but I don’t understand how your system looks like and what devices are connected. A schematics (drawing or model) would be useful.
the full draw is like that:
I am not sure how to give the data of gas inlet?
For the outlet, disable outgassing. No gas is inserted (switch Cosine to None).
For the inlet, you have to set the absolute outgassing (mbar.l/s, first checkbox).
It is up to you to know the outgassing rate. You can use the equation Q=PS, so if your inlet pressure is P, and the flow rate is S, then PS outgassing rate (converted to mbar.l/s) needs to be set.
In the example you gave (0.83l/s, 1000mbar), the pressure would be way over Molflow’s validity limit (around 1E-3mbar), hence pumping from atmosphere cannot be simulated with this code assuming molecular flow.
After setting up a certain outgassing, you can use any facet inside the geometry to check for pressure. Since high vacuum is linear, you can scale the outgassing linearly to achieve the target pressure of 1e-7mbar.
For the inlet, I want to use target vacuum pressure 1E-7mbar to multiply the flow rate: Q=PS= 0.83*1e-7=8.3E-8, but I am not sure if this kind of hypothesis Pressure is acceptable or not. The problem is I don’t have the pressure data for inlet side.
Yes, that is applicable. The pressure inside the tank will be lower than 1E-7mbar, but right at the inlet point it will be indeed 1E-7mbar if you inject 8.3E-8mar.l/s
Thanks a lot. Use 1E-7 mbar, So that I can check if 0.83L/s can meet our vacuum target. If not, I can give a suggestion pump speed. For your guidance, I get a good result the min pressure 1.9e-8mbar, it is better than 1E-7mbar. Maybe later I can change the pump speed to get a limited gas in speed.
I think this on the left side is a modeling error, maybe a non-transparent facet, be careful.
Thanks for your careful reminding, I rechecked again. It is wrong for input data because I changed the material proposal data many times. I modified it.
