Modifying self-assembly and species separation in three-dimensional systems of shape-anisotropic particles

Windows-Yule, Kit; Scheper, Bert J.; Otter, Wouter K. den; Parker, D.J.; Thornton, Anthony Richard

doi:10.1103/physreve.93.020901

Cited by 15 publications

(8 citation statements)

References 80 publications

(109 reference statements)

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“…The tendency of h particles to occupy convex-as opposed to concave-regions also makes sense in terms of energy minimization, as particles in these regions possess a lower average center of mass. Energy minimization has indeed recently been shown to be a key driving factor in the segregative behaviors of (vibrofluidized) granular beds [59].…”

Section: Results and Analysismentioning

confidence: 99%

Inducing Axial Banding in Bidisperse-by-Density Granular Systems Using Noncylindrical Tumbler Geometries

et al. 2017

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We present evidence of axial banding in rotated, binary granular beds comprising particles of equal size but differing material density. It is demonstrated that the presence of differing particle densities alone may produce limited, localized axial segregation arising due to end-wall effects, but that true axial banding, i.e., axial segregation patterns pervading the full extent of the system may be induced through the use of a rotating tumbler whose internal geometry comprises alternating convex and concave segments. The segregation patterns formed are observed to be stable and reproducible, unlike the unpredictable, metastable banding typically observed in systems containing particles differing in size. Moreover, we demonstrate that, by varying the axial extent and positioning of the individual convex and concave segments, the system geometry may be deliberately tuned in order to directly control both the positions and the widths of the axial bands produced-a finding with significant potential benefits for a range of industrial processes.

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Section: Results and Analysismentioning

confidence: 99%

Inducing Axial Banding in Bidisperse-by-Density Granular Systems Using Noncylindrical Tumbler Geometries

et al. 2017

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“…The term 'granular segregation' refers to the partial or complete separation of a multicomponent particulate system into its individual constituents. The segregation of excited granular mixtures occurs spontaneously, based on differences in, for instance, size [38,39], density [40,41], geometry [42,43] or elastic [44,45] or frictional [46] properties between particles. In the current work, we focus on density-driven segregation, investigating systems of particles possessing identical sizes, geometries and contact properties, differing only in their densities and, hence, masses.…”

Section: Granular Segregationmentioning

confidence: 99%

Convection and segregation in fluidised granular systems exposed to two-dimensional vibration

Windows-Yule

2016

New J. Phys.

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Convection and segregation in granular systems not only provide a rich phenomenology of scientifically interesting behaviours but are also crucial to numerous 'real-world' processes ranging from important and widely used industrial procedures to potentially cataclysmic geophysical phenomena. Simple, small-scale experimental or simulated test systems are often employed by researchers in order to gain an understanding of the fundamental physics underlying the behaviours of granular media. Such systems have been the subject of extensive research over several decades, with numerous system geometries and manners of producing excitation explored. Energy is commonly provided to granular assemblies through the application of vibration-the simplicity of the dynamical systems produced and the high degree of control afforded over their behaviour make vibrated granular beds a valuable canonical system by which to explore a diverse range of phenomena. Although a wide variety of vibrated systems have been explored in the existing literature, the vast majority are exposed to vibration along only a single spatial direction. In this paper, we study highly fluidised systems subjected to strong, multi-directional driving, providing a first insight into the dynamics and behaviours of these systems which may potentially hold valuable new information relevant to important industrial and natural processes. With a particular focus on the processes of convection and segregation, we analyse the various states and phase transitions exhibited by our system, detailing a number of previously unobserved dynamical phenomena and system states.

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“…The granular mixtures handled in industries, such as coke-limestone-iron ore mixtures in steel industries, powders in pharmaceutical industries, limestone-clay mixtures in cement industries, sand-gravel-cement mixtures in construction industries, etc., are composed of spherical and nonspherical particles. Such mixtures often exhibit demixing or segregation [1][2][3][4] during pouring, tumbling, shaking, and conveying, due to the species differing in size [4][5][6][7][8][9][10][11][12][13][14][15] , density 6,8,[16][17][18][19][20] , shape [21][22][23][24][25][26][27][28][29][30][31][32][33][34] , and mechanical properties, such as friction coefficient [35][36][37][38][39] and restitution coefficient [40][41][42] . The segregation is unwanted and needs in-depth understanding since it affects product quality …”

Section: Introductionmentioning

confidence: 99%

Dense granular flow of mixtures of spheres and dumbbells down a rough inclined plane: Segregation and rheology

Mandal

Khakhar

2019

Physics of Fluids

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We study the flow of equal-volume binary granular mixtures of spheres and dumbbells with different aspect ratios down a rough inclined plane, using the discrete element method. We consider two types of mixtures -in the first type the particles of the two species have equal volume but different aspect ratios (EV) and in the second type they have variable volumes and aspect ratios (VV). We also use mixtures of spheres of two different sizes (SS) with the same volume ratios as in the mixtures of the second type, as the base case. Based on the study of Guillard, Forterre and Pouliquen [J. Fluid Mech. 807, R1-R11 (2016)], the inclination angle of the base for each mixture is adjusted and maintained at a high value to yield the same pressure and shear stress gradients for all mixtures and a high effective friction (µ) for each. This ensures that the segregation force and resulting extent of segregation depend only the size and shape of the particles. The species with larger effective size, computed in terms of the geometric mean diameter, floats up in all cases and the dynamics of the segregation process for all the mixtures are reported. The concentration profiles of the species at steady state agree well with the predictions of a continuum theory. The µ − I and φ − I scaling relations, where I is the inertial number and φ is the solid volume fraction, extended to the case of mixtures, are shown to describe the rheology for all the cases.

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Modifying self-assembly and species separation in three-dimensional systems of shape-anisotropic particles

Cited by 15 publications

References 80 publications

Inducing Axial Banding in Bidisperse-by-Density Granular Systems Using Noncylindrical Tumbler Geometries

Inducing Axial Banding in Bidisperse-by-Density Granular Systems Using Noncylindrical Tumbler Geometries

Convection and segregation in fluidised granular systems exposed to two-dimensional vibration

Dense granular flow of mixtures of spheres and dumbbells down a rough inclined plane: Segregation and rheology

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