Next Article in Journal
Multi-Party Quantum Summation Based on Quantum Teleportation
Previous Article in Journal
Efficiency Bounds for Minimally Nonlinear Irreversible Heat Engines with Broken Time-Reversal Symmetry
Previous Article in Special Issue
A Note on the Entropy Force in Kinetic Theory and Black Holes
Article Menu
Issue 7 (July) cover image

Export Article

Open AccessFeature PaperArticle

On the Rarefied Gas Experiments

1
Department of Energy Engineering, Faculty of Mechanical Engineering, Budapest University of Technology and Economics (BME), 1111 Budapest, Hungary
2
Department of Theoretical Physics, Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, 1121 Budapest, Hungary
3
Montavid Thermodynamic Research Group, 1112 Budapest, Hungary
Entropy 2019, 21(7), 718; https://doi.org/10.3390/e21070718
Received: 6 July 2019 / Revised: 20 July 2019 / Accepted: 22 July 2019 / Published: 23 July 2019
(This article belongs to the Special Issue Entropy and Non-Equilibrium Statistical Mechanics)
  |  
PDF [597 KB, uploaded 23 July 2019]
  |  

Abstract

There are limits of validity of classical constitutive laws such as Fourier and Navier-Stokes equations. Phenomena beyond those limits have been experimentally found many decades ago. However, it is still not clear what theory would be appropriate to model different non-classical phenomena under different conditions considering either the low-temperature or composite material structure. In this paper, a modeling problem of rarefied gases is addressed. The discussion covers the mass density dependence of material parameters, the scaling properties of different theories and aspects of how to model an experiment. In the following, two frameworks and their properties are presented. One of them is the kinetic theory based Rational Extended Thermodynamics; the other one is the non-equilibrium thermodynamics with internal variables and current multipliers. In order to compare these theories, an experiment on sound speed in rarefied gases at high frequencies, performed by Rhodes, is analyzed in detail. It is shown that the density dependence of material parameters could have a severe impact on modeling capabilities and influences the scaling properties. View Full-Text
Keywords: rarefied gases; non-equilibrium thermodynamics; kinetic theory rarefied gases; non-equilibrium thermodynamics; kinetic theory
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Kovács, R. On the Rarefied Gas Experiments. Entropy 2019, 21, 718.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Entropy EISSN 1099-4300 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top