Thermophoresis in gases

Bakanov, S.P.; Deryagin, B. V.; Roldugin, V. I.

doi:10.1070/pu1979v022n10abeh005616

Cited by 20 publications

(12 citation statements)

References 6 publications

(4 reference statements)

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“…The concept was first proposed by Deryagin and his coworkers [1][2][3][4] and has been studied experimentally both in ionic 3,5,6 and nonionic solutions. 7,8 In a solution of uncharged solute, for example, small aerosol particles floating in the atmosphere, 9,10 the solute molecules interact with the aerosol particles through the van der Waals and dipole forces. If the interaction between the solute molecules and the particle is attractive, the particle migrates toward the region of higher solute concentration, whereas the movement is toward lower solute concentration if the interacting force is repulsive.…”

Section: Introductionmentioning

confidence: 99%

Diffusiophoresis of a Spherical Particle Normal to a Plane

Lou

Lee

2008

J. Phys. Chem. C

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Diffusiophoresis of a spherical colloidal particle normal to a plane subject to a uniform electrolyte concentration gradient is investigated theoretically for arbitrary double layer thickness and surface potential. The governing general electrokinetic equations are put in terms of bipolar spherical coordinates and solved numerically with a pseudospectral method based on Chebyshev polynomial. The effects of key parameters are examined such as the double layer thickness, surface potential, and the distance between the particle and the plane. It is found, among other things, that the presence of the boundary has a retardation effect on the motion of the particle, provided that the double layer does not touch the planar boundary. If it does, however, the velocity of the particle will exhibit a maximum as the double layer just loses touch of the plane, thanks to the competitive force of the polarization effect. The planar boundary poses not only as a conventional hydrodynamic retarding force, but also may distort the shape of the double layer greatly, hence altering its polarization situation, which has a profound electrostatic impact on the motion of the particle when it is close to the plane.

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Section: Introductionmentioning

confidence: 99%

Diffusiophoresis of a Spherical Particle Normal to a Plane

Lou

Lee

2008

J. Phys. Chem. C

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“…It is important to note that it is sufficient to solve Equation (1) for a flat boundary because the corrections due to finite curvature are of second order of the Knudsen number. In the papers [11][12][13][14], it was shown that the normal component of heat flux and temperature are discontinuous near the boundary of solid. In this case, the boundary conditions have the form (5):…”

Section: Basic Concepts Of Low Knudsen Gas Dynamicsmentioning

confidence: 99%

“…The boundary conditions for thermal conductivity describe the jumps of temperature and the normal component of heat flux. These boundary conditions were discussed in a series of publications [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Effective thermal conductivity of inhomogeneous medium containing gas‐filled inclusions

Markov¹,

Levin²,

Mousatov³

et al. 2015

Math Methods in App Sciences

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Communicated by W. SprößigDetermination of effective physical parameters of gas-filled porous media is of practical interest to a wide spectrum of applications from construction industry to petrophysics. The classical equations of thermal conductivity are not applicable for sufficiently small pores, the characteristic size of which is comparable with the mean free path of gas molecules. In this case, for description of the gas behavior, it is necessary to use the methods of physical kinetics and rarefied gas dynamics. In this work, we have considered so-called slip flow regime, 0 < Kn < 1, where Kn D =R is the Knudsen number, is the mean free path, and R is the characteristic pore size. In this regime, we can use the classical equations of mechanics of continuum media with modified boundary conditions that take into account the temperature and energy flux jumps on the pore boundaries. We have solved the so-called one-particle problem of thermal polarization of gas-filled inclusion. The obtained solution was then used in some self-consistent homogenization methods to calculate the effective conductivity coefficient. Our calculations have shown that the effective conductivity depends substantially on the pore size (the Knudsen number). The obtained results demonstrate the feasibility of pore sizes determination by using measurements of effective thermal conductivity.

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“…These forces arise due to the kinetic slip of a fluid flow near the particle in the presence of the temperature gradient along its surface. 3,4 When temperature gradient is caused by an external source then the magnitude of the effect depends upon thermal conductivity of a host medium 1 and of the particle p . In the limiting case when p →ϱ this effect disappears.…”

Section: Introductionmentioning

confidence: 99%

“…Although the effect of ther-mophoresis was discovered more than one hundred years ago ͑see, e.g., Ref. 4 and references therein͒ the feasibility of the thermophoretic self-action of a heat releasing particle near the interface was not discussed before. The obtained results imply that a heat releasing ͑absorbing͒ particle is attracted ͑repelled͒ to the interface when thermal conductivity of a host medium is less than thermal conductivity of the adjacent medium.…”

Section: Introductionmentioning

confidence: 99%

Thermophoretic interaction of heat releasing particles

Dolinsky

Elperin

2003

Journal of Applied Physics

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A theory to describe heat transfer during laminar incompressible flow of a fluid in periodic porous media This study investigates thermophoretic force acting at heat releasing ͑absorbing͒ particles near the interface between two media with different thermal conductivities. This force is caused by the induced temperature gradient which is proportional to the rate of heat release ͑absorption͒ by the particle. Therefore the magnitude of the thermophoretic force is proportional to the rate of heat release ͑absorption͒ by the particle, and its direction depends upon the sign of the parameter 1 -2 , where 1 is thermal conductivity of a host medium and 2 is thermal conductivity of the adjacent medium. The obtained results imply that a heat releasing ͑absorbing͒ particle is attracted ͑repelled͒ to the interface when thermal conductivity of a host medium is less than thermal conductivity of the adjacent medium. Thus, e.g., growing in air by condensation particle is attracted to a metal surface while an evaporating in air particle is repelled from a metal surface. The change of temperature distribution caused by heat releasing particles results in the additional thermophoretic interaction of these particles. We determined a condition for mutual attraction of two spherical heat releasing particles and derived an expression for the thermophoretic force acting at the particles. The magnitudes of the considered thermophoretic forces are compared with the classic thermophoretic force.

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Thermophoresis in gases

Cited by 20 publications

References 6 publications

Diffusiophoresis of a Spherical Particle Normal to a Plane

Diffusiophoresis of a Spherical Particle Normal to a Plane

Effective thermal conductivity of inhomogeneous medium containing gas‐filled inclusions

Thermophoretic interaction of heat releasing particles

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