[HN Gopher] What Is a Supercritical Fluid?
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What Is a Supercritical Fluid?
Author : simonebrunozzi
Score : 14 points
Date : 2022-03-31 08:59 UTC (2 days ago)
(HTM) web link (www.scimed.co.uk)
(TXT) w3m dump (www.scimed.co.uk)
| bernulli wrote:
| There is nothing magical about a supercritical fluid (SCF), i.e.
| a fluid at a state that has a temperature and pressure higher
| than the respective critical values. The article repeats the same
| crap that you read other places: it does _not_ have liquid and
| gaseous properties simultaneously. At low temperatures, the SCF
| is a liquid; at high temperatures (and not too high supercritical
| pressures), it 's a gas or even an ideal gas. The 4-quadrant way
| of showing the 'supercritical domain' is super misleading in this
| way. Nothing happens when you cross those imaginary boundaries.
|
| What _is_ almost magical is a fluid at _near-critical_
| conditions. There 's a whole lot going on we don't properly
| understand yet.
| longemen3000 wrote:
| i'm working on calculating thermodynamic properties from
| equations of state [1], and yeah, looking for criteria on how
| to distinguish from a low pressure, a near critical pressure
| and a supercritical pressure is not trivial, specially when you
| don't know the critical point of a fluid (the case for all
| molecular EoS). one property i've relying on is that the second
| virial coefficient minimum density is always lower than the
| saturated gas density.. until a threshold near criticality. a
| lot of assumptions about a thermodynamic model fail at near-
| critical points. Understanding and exploiting those properties
| helps on building more accurate property solvers for any,
| existing or new, equations of state.
|
| [1] https://github.com/ypaul21/Clapeyron.jl
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