[PATCH 3/3] gas pressures: use an actual compressibility table for air

Dirk Hohndel dirk at hohndel.org
Wed Feb 24 16:05:28 PST 2016


On Wed, Feb 24, 2016 at 03:58:41PM -0800, Linus Torvalds wrote:
> On Feb 24, 2016 15:43, "Dirk Hohndel" <dirk at hohndel.org> wrote:
> >
> > But this bothers me. from 60 to 80 to 100 bar the z_factor goes UP!
> > That just seems wrong. Maybe there's something in the physics that I don't
> > get that makes this a magic range, but still... this at least needs an
> > explanation.
> 
> I have no idea of what the physical explanation is, but if you look at the
> compressibility graphs it turns out to not even be hugely unusual. To use a
> highly technical term, they are some "funky shit".
> 
> Richard pointed to another table (on baue.org) of compressibility values
> that had other gasses, and that had oxygen with even more of a dip (it's at
> 5% smaller volume than you'd expect at just 1300psi). So it compresses
> *better* than you'd expect, more so than pure air.
> 
> I may be misusing and misunderstanding the Z factor, but yeah, I found it
> surprising too.

OK, so I'll take the patch as is and wait for Robert to curse me - or send
a different patch :-)

/D


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