Valid to use Molflow for HV (not UHV)?

General discussion
1

Want to optimize a vacuum system with volume ~200 liters or so and diameter < 1 meter and about a foot wide, roughly. This is being pumped by a 10" diffusion pump.

Expect to get to low 10E-5 Torr to high 10E-6 Torr range.
Seems mean free path in this case is larger than system dimensions, but not by a whole lot.

So, I want to use Molflow, but not 100% sure it makes sense.
I’d like to claim that the low vacuum performance doesn’t really matter and it’s really the performance at 10E-6 range that I should be optimizing. And, that Molflow makes sense to use here in this case.
Is this a valid argument?

Thanks for any feedback.

2

Hello Ray:

1E-5 Torr has a mean-free path of around a few meters (depending on gas) so you can confidently use Molflow+ to simulate such a system. Even when MFP~Diameter of the chamber i.e. Knudsen number close to 1, the difference between Molflow+ results and DSMC or Boltzmann equation which I’ve benchmarked on several papers is very minimal, since the molecules collide very rarely with other molecules.

3

@rkerseva Thanks! That’s what I was hoping to hear!