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An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Dynamics and Thermodynamics beyond the critical point
F A Gorelli1, T Bryk, M Krisch
1IPCF-CNR, UOS Roma, I-00185 Roma, Italy.
Scientific Reports
|February 6, 2013
Summary
Supercritical fluids exhibit complex dynamics, with sound propagation revealing a distinct crossover between gas-like and liquid-like behaviors. This dynamic line challenges traditional thermodynamics, indicating a richer supercritical state than previously understood.
Area of Science:
- Thermodynamics
- Fluid Dynamics
- Physical Chemistry
Background:
- Thermodynamics defines a single phase beyond the critical point.
- Supercritical fluids possess unique properties between gas and liquid states.
- Understanding supercritical fluid dynamics is crucial for various applications.
Purpose of the Study:
- To investigate the dynamical properties of a supercritical fluid model.
- To identify and characterize dynamic crossovers in the supercritical region.
- To explore the complexity of the supercritical state beyond established thermodynamic notions.
Main Methods:
- Simulating a supercritical fluid model across a range of pressures and temperatures.
- Analyzing sound propagation in the Terahertz frequency region.
- Identifying dynamic crossovers along isotherms.
Main Results:
- Observed sudden changes in dynamical properties as a function of pressure and temperature.
- Detected a sharp dynamic crossover between gas-like and liquid-like regimes.
- Found an interplay between acoustic and heat waves at low densities.
- Determined a dynamic line in the phase diagram correlated with thermodynamic observables.
Conclusions:
- The supercritical state is significantly more complex than previously assumed.
- A dynamic line can be defined, reflecting complex behavior.
- Sound propagation measurements reveal distinct dynamic regimes in supercritical fluids.
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