Extraction of the translational Eucken factor from light scattering by molecular gas

Wu，Lei1; Li，Qi1; Liu，Haihu2; Ubachs，Wim3

2020

10.1017/jfm.2020.568

JOURNAL OF FLUID MECHANICS   影响因子和分区

0022-1120

1469-7645

Although the thermal conductivity of molecular gases can be measured straightforwardly and accurately, it is difficult to experimentally determine its separate contributions from the translational and internal motions of gas molecules. Yet, this information is critical in rarefied gas dynamics as the rarefaction effects corresponding to these motions are different. In this paper, we propose a novel methodology to extract the translational thermal conductivity (or equivalently, the translational Eucken factor) of molecular gases from the Rayleigh-Brillouin scattering (RBS) experimental data. From the numerical simulation of the Wu et al. (J. Fluid Mech., vol. 763, 2015, pp. 24-50) model we find that, in the kinetic regime, in addition to bulk viscosity, the RBS spectrum is sensitive to the translational Eucken factor, even when the total thermal conductivity is fixed. Thus it is not only possible to extract the bulk viscosity, but also the translational Eucken factor of molecular gases from RBS light scattering spectra measurements. Such experiments bear the additional advantage that gas-surface interactions do not affect the measurements. By using the Wu et al. model, bulk viscosities (due to the rotational relaxation of gas molecules only) and translational Eucken factors of, and are simultaneously extracted from RBS experiments.

rarefied gas flow

SCI ; EI

英语

第一 ; 通讯

National Natural Science Foundation of China[51876170] ; Natural Science Basic Research Plan in Shaanxi Province of China[2019JM-343] ; National Key Research and Development Project of China[2016YFB0200902]

Mechanics ; Physics

Mechanics ; Physics, Fluids & Plasmas

WOS:000563009100001

CAMBRIDGE UNIV PRESS

20203709152244

Molecules ; Viscosity ; Flow of gases ; Brillouin scattering ; Gas dynamics ; Thermal conductivity of gases

Fluid Flow, General:631.1 ; Gas Dynamics:631.1.2 ; Thermodynamics:641.1 ; Light/Optics:741.1 ; Physical Properties of Gases, Liquids and Solids:931.2 ; Atomic and Molecular Physics:931.3

ENGINEERING

2-s2.0-85090315814

Scopus

1.Department of Mechanics and Aerospace Engineering,Southern University of Science and Technology,Shenzhen,518055,China
2.School of Energy and Power Engineering,Xi'an Jiaotong University,Xi'an,710049,China
3.Department of Physics and Astronomy,LaserLaB,Vrije Universiteit,Amsterdam,De Boelelaan 1081,1081 HV,Netherlands

Wu，Lei,Li，Qi,Liu，Haihu,et al. Extraction of the translational Eucken factor from light scattering by molecular gas[J]. JOURNAL OF FLUID MECHANICS,2020,901.

Wu，Lei,Li，Qi,Liu，Haihu,&Ubachs，Wim.(2020).Extraction of the translational Eucken factor from light scattering by molecular gas.JOURNAL OF FLUID MECHANICS,901.

Wu，Lei,et al."Extraction of the translational Eucken factor from light scattering by molecular gas".JOURNAL OF FLUID MECHANICS 901(2020).