[FIXED PATCH 3/2] gas model: add polynomials for Z factors of oxygen/nitrogen/helium

[Dirk Hohndel]

On Wed, Mar 02, 2016 at 06:14:35PM -0800, Linus Torvalds wrote:
> On Wed, Mar 2, 2016 at 5:55 PM, Linus Torvalds
> <torvalds at linux-foundation.org> wrote:
> >
> > Having a curve that goes all the way to 500 bar (like the air one we
> > have - that polynomial looks good all the way) would be nicer, of
> > course.
> 
> Don't get me wrong. I don't think 500 bar is relevant. It's more the
> fact hat I worry that with our tables going up only to 275 bar (for
> the non-air gases), any pressure above that is kind of questionable.
> 
> From just eyeballing the plots on Wolfram Alpha, I think all the
> polynomials looked fine to 300 bar. They didn't look *horrible* up to
> 400 bar either. The Oxygen one was the worst by far past 400 bar, the
> others didn't look too nasty.

It will be a long time before we see 400 bar cylinders in use. Even 300
bar cylinders - while they exist - are excessively rare. I know a German
who bought one and has yet to find a place that fills beyond 260 bar.

/D