Vibration-induced size separation in granular media: The convection connection

Knight, James B.; Jaeger, Heinrich M.; Nagel, Sidney R.

doi:10.1103/physrevlett.70.3728

Cited by 639 publications

(372 citation statements)

References 20 publications

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“…Binders were used to freeze the particles in place and then slice the solidified structures to reveal the internal structures. At high , they found that while a single large particle in a bed of small particles rose to the top as described by Knight et al [22], a homogeneous spatial distribution was observed with a 50-50 binary mixture (see figure 16(a)). The bed surface was flat in this regime.…”

Section: Effect Of Convection On Segregation and Mixingmentioning

confidence: 79%

“…Nonetheless, it is clear that the size separation phenomena in binary mixtures are qualitatively different from those observed in the intruder system. To understand if mixing will indeed occur in a situation as in the experiments of Knight et al [22], let us consider a situation where a large particle travels to the top and stays there because it is too large to enter the thin boundary layer with downward moving particles. If one keeps adding a large particle to the initial mixture, one will reach a point eventually where a sizable number of large particles will accumulate at the top and near the boundaries.…”

Section: Effect Of Convection On Segregation and Mixingmentioning

confidence: 99%

“…(b) The large particle can sink to the bottom of a V-shaped container when reverse convection is set up. From [22].…”

Section: Experiments In the Convectivementioning

confidence: 99%

“…Knight and co-workers [22] observed that boundaries can have a significant impact on segregation. It was shown that frictional interaction of the grains with the side walls can set up convection which can cause an intruder to even go to the bottom, depending on the shape of the container.…”

Section: Introductionmentioning

confidence: 99%

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The theory of gradient vibratory segregation effect as applied to screening process

Blekhman¹,

Vasilkov²,

Yakimova³

2015

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We review recent developments in size separation in vibrated granular materials. Motivated by a need in industry to handle granular materials efficiently and a desire to make fundamental advances in non-equilibrium physics, experimental and theoretical investigations have shown size separation to be a complex phenomenon. Large particles in a vibrated granular system normally rise to the top. However, they may also sink to the bottom or show other patterns, depending on subtle variations in physical conditions. While size ratio is a dominant factor, particle-specific properties such as density, inelasticity and friction can play an important role. The nature of the energy input, boundary conditions and interstitial air have also been shown to be significant factors in determining spatial distributions. The presence of convection can enhance mixing or lead to size separation. Experimental techniques including direct visualization and magnetic resonance imaging are being used to investigate these properties. Molecular dynamics and Monte Carlo simulation techniques have been developed to probe size separation. Analytical methods such as kinetic theory are being used to study the interplay between particle size and density in the vibro-fluidized regime, and geometric models have been proposed to describe size separation for deep beds. Besides discussing these studies, we will also review the impact of inelastic collisions and friction on the density and velocity distributions to gain a deeper appreciation of the non-equilibrium nature of the system. While a substantial number of studies have been performed, considerable work is still required to achieve a firm description of the phenomena.

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Section: Effect Of Convection On Segregation and Mixingmentioning

confidence: 79%

Section: Effect Of Convection On Segregation and Mixingmentioning

confidence: 99%

“…(b) The large particle can sink to the bottom of a V-shaped container when reverse convection is set up. From [22].…”

Section: Experiments In the Convectivementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The theory of gradient vibratory segregation effect as applied to screening process

Blekhman¹,

Vasilkov²,

Yakimova³

2015

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“…In the convection model, it is assumed that particles in a shaking recipient undergo a convective flow, rising at the middle and falling at the sides. Segregation occurs because the large particles, once swept up to the top of the recipient, cannot be entrained into the downflow through the very narrow outer region of downward motion, staying at the top of the bed (Knight et al, 1993;Shinbrot and Muzzio, 1998). Other possible mechanisms are still under investigation, among them condensation, granular diffusion, controlled reorganization, entropy (in a zero gravity environment) and the inertial mechanism (Hong et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Effects of binary particle size distribution on the fluid dynamic behavior of fluidized, vibrated and vibrofluidized beds

Daleffe

Ferreira

Freire

2008

Braz. J. Chem. Eng.

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-In this work the effects of particle size distribution on the dynamics and segregation patterns in fluidized, vibrated and vibrofluidized beds were investigated. A binary particle size distribution and a reference one composed of glass spheres with a mean Sauter diameter of 2.18×10 -3 m were tested. The experimental setup consisted basically of a circular glass chamber with a height of 0.50 m and a diameter of 0.114 m, operated in the fluidized bed mode ( = 0.00), in either vibrated or vibrofluidized bed modes ( = 2.00). The pressure drops in the fluidized and vibrofluidized beds were not significantly affected by the binary particle size distribution. Well-defined segregation patterns occurred in fluidized and vibrated beds with small particles concentrating at the top and large particles at the bottom in the first situation and the reverse in the second one. Segregation patterns in vibrofluidized beds depended on the values of vibration parameters. Segregation in vibrofluidized and vibrated beds was minimized by operating at a high amplitude of vibration.

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The Inelastic Maxwell Model

Ben‐Naim

Krapivsky

2004

The Physics of Granular Media

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Vibration-induced size separation in granular media: The convection connection

Cited by 639 publications

References 20 publications

The theory of gradient vibratory segregation effect as applied to screening process

The theory of gradient vibratory segregation effect as applied to screening process

Effects of binary particle size distribution on the fluid dynamic behavior of fluidized, vibrated and vibrofluidized beds

The Inelastic Maxwell Model

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