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.

Modelling of a compressible fluid

Please login with a confirmed email address before reporting spam

Hello,

I'm already a "medium level" user of COMSOL (Vers. 3.5), but as an electrical engineer, I'm lacking in the needed physics knowledge for the following problem:

I'd like to understand gas flow a little bit better in a PECVD system I've developped. I'd like to modell the gas flow from the entry point of the showerhead (which distributes the gas in the recipient) until the exit (pumping port) of the recipient.
(For those of you not familiar with a PECVD system: The process gas enters the reaction chamber through a flat, hollow plate with an array of small holes drilled in it, called showerhead. From the showerhead, the gas spreads out evenly onto the substrates, where it reacts to a solid substance, with the help of heat and plasma).

With the humble knowledge I have in fluid modelling, I guess that this problem can't be modelled with the incompressible navier-stokes, as the process gas enters the showerhead with a quite high pressure (500 - 1000 mbar absolute), while the pressure in the reaction chamber is only some 2 - 10 mbar absolute.

For me it's important to see the flow properties before and after the small holes in the showerhead. So the model has to include the strong decrease in gas density, when the gas streams out of the showerhead.

Is there a way to solve this problem with COMSOL with moderate expense of time?
Could this be done somehow with the Euler-Equation or a modification of the incompressible mode?

-A 2D-Model / 2D-Axisymmetric-Model is enough.
-Heat transfer can be neglected.
-I'm happy with a approximative result. I don't need 99.9% match to reality.

Many thanks for your help in advance!

Best regards,
Alex Stettler

1 Reply Last Post 9 nov. 2009, 11:07 UTC−5
COMSOL Moderator

Hello Alexander Stettler

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.


Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 9 nov. 2009, 11:07 UTC−5
Hi

I am a beginner at using COMSOL and i also have electrical engineering background. I am trying to model the gas flow inside the plasma etch reactor having the gas inflow through an annulus (which distributes the gas in the reactor) until the exit (pumping port) of the reactor. I am operating in the pressure range of 10-50mTorr.

I want to model the time multiplexed ("e.g;switching the gas at the input after every two seconds at a known flowrate") gas flow (transport) inside a reactor and see how one gas replaces the other inside the reactor.

Is there a way to solve this problem with COMSOL ...

-A 2D-Axisymmetric-Model is enough.
-Heat transfer can be neglected.
-I'm happy with a approximative result.

Thanking you in anticipation....

Best regards,
Iqbal
Hi I am a beginner at using COMSOL and i also have electrical engineering background. I am trying to model the gas flow inside the plasma etch reactor having the gas inflow through an annulus (which distributes the gas in the reactor) until the exit (pumping port) of the reactor. I am operating in the pressure range of 10-50mTorr. I want to model the time multiplexed ("e.g;switching the gas at the input after every two seconds at a known flowrate") gas flow (transport) inside a reactor and see how one gas replaces the other inside the reactor. Is there a way to solve this problem with COMSOL ... -A 2D-Axisymmetric-Model is enough. -Heat transfer can be neglected. -I'm happy with a approximative result. Thanking you in anticipation.... Best regards, Iqbal

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.