Measurements of thermophoretic velocities of aerosol particles in microgravity conditions in different carrier gases / Prodi F.,Santachiara G.,Di Matteo L.,Vedernikov A.,Beresnev S. A.,Chernyak V. G. // JOURNAL OF AEROSOL SCIENCE. - 2007. - V. 38, l. 6. - P. 645-655.

ISSN/EISSN:

0021-8502 / нет данных

Type:

Article

Abstract:

Measurements of the thermophoretic velocities of aerosol particles (paraffin) in different carrier gases (helium, nitrogen, argon, xenon) were performed in microgravity conditions (the drop tower facility, in Bremen). The experiments permitted the study of thermophoresis in conditions which minimize the impact of gravity. Monodisperse aerosol particles were observed through a digital holographic velocimeter, a device allowing the determination of 3-D coordinates of particles in the viewing volume. Particle trajectories, and consequently particle velocities, were reconstructed by analysing the sequence of particle positions. We successfully observed thermophoretic velocities in low-gravity conditions. The experiments show that the thermophorefic velocity decreases from helium (He) to nitrogen (N-2), argon (At), and xenon (Xe). Talbot et al. {[}1980. Thermophoresis of particles in a heated boundary layer. Journal of Fluid Mechanics 101, 737-758] predict thermophorefic velocities that nearly equal the observed values in Xenon, but are larger than observed values in N-2 and Ar and smaller than the observed values in He. Yamamoto and Ishihara {[}1988. Thermophoresis of a spherical particle in a rarefied gas of a transition regime. Physics of Fluids 31, 3618-3624] predict thermophoretic velocities that are smaller than observed values and also predict negative values in N-2, Ar and Xe. Beresnev's theory {[}1995. Thermophoresis of a spherical particle in a rarefied gas: Numerical analysis based on the model kinetic equations. Physics of Fluids 7, 1743-1756] fits the experimental data well when the coefficient of tangential momentum accommodation is set to one and the coefficient of energy accommodation is set to a value between 0.4 and 0.9, depending upon the gas. (c) 2007 Elsevier Ltd. All rights reserved.

Author keywords:

thermophoresis; microgravity; accommodation coefficient; thermophoretic velocity LINEARIZED BOLTZMANN-EQUATION; SPHERICAL-PARTICLE; RAREFIED-GAS; THERMAL FORCES; MOTION

DOI:

10.1016/j.jaerosci.2007.04.002

Web of Science ID:

ISI:000248775500006

Соавторы в МНС:

Другие поля

Поле	Значение
Month	JUN
Publisher	PERGAMON-ELSEVIER SCIENCE LTD
Address	THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND
Language	English
Keywords-Plus	LINEARIZED BOLTZMANN-EQUATION; SPHERICAL-PARTICLE; RAREFIED-GAS; THERMAL FORCES; MOTION
Research-Areas	Engineering; Environmental Sciences \& Ecology; Meteorology \& Atmospheric Sciences
Web-of-Science-Categories	Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology \& Atmospheric Sciences
Author-Email	g.santachiara@isac.cnr.it
ResearcherID-Numbers	Beresnev, Sergey/P-2426-2014
ORCID-Numbers	Vedernikov, Andrei/0000-0002-2269-0853
Number-of-Cited-References	35
Usage-Count-Last-180-days	2
Usage-Count-Since-2013	7
Journal-ISO	J. Aerosol. Sci.
Doc-Delivery-Number	200PO