The influence of end walls on the segregation pattern in a horizontal rotating drum

Arntz, M. M. H. D.; Otter, Wouter K. den; Beeftink, H.H.; Boom, R.M.; Briels, Willem J.

doi:10.1007/s10035-012-0386-4

Cited by 20 publications

(13 citation statements)

References 29 publications

(47 reference statements)

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“…3(b). This is in line with the previous reports that the flow velocity of the grains is lower in the middle than that near the front wall of the drum for the wall effect [26,27]. The stability of the signals would indicate that the visually observed mound is appearing only near the end walls and does not influence the avalanche dynamics in the middle of the drum.…”

Section: Avalanche Statisticssupporting

confidence: 80%

Time-resolved granular dynamics of a rotating drum in a slumping regime as revealed by speckle visibility spectroscopy

et al. 2017

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Abstract. Granular materials in rotating drums are of wide interest not only because of their extensive use in the industrial contexts, but also as model systems in the study of natural disasters, such as avalanches or landslides. Most of available experimental methods are restricted to surface layer flows and dilute systems whilst the remainder can only resolve the granular dynamics to a fine scale with relatively poor temporal resolution or vice versa. In contrast, speckle visibility spectroscopy (SVS) is able to resolve the average of the three components of motion of grains in dense systems in small volume of granular media several layer deep with spatio-temporal resolutions that allow the probing of the granular micro-dynamics. We have used this technique to study granular dynamics of surface avalanche flow in the slumping regime using both spherical glass and irregular sand particles. Although results are very similar, we determined that visually observed compaction at the beginning of avalanche process for irregular sand particles influence time evolution of the particle fluctuation velocity during avalanches.

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Section: Avalanche Statisticssupporting

confidence: 80%

Time-resolved granular dynamics of a rotating drum in a slumping regime as revealed by speckle visibility spectroscopy

et al. 2017

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“…We use particles of d = 4.0, 2.5 mm, in an equal volume distribution. The rapid axial segregation happens only with a convex-concave (pentagon-pentagram) combination, as for convex shapes there exists little difference in the level of the flow, just the length of avalanching layer [50]. We performed several experiments, putting together circular and square sections, pentagonal and square, and differently oriented square sections.…”

Section: Shape-induced Axial Segregationmentioning

confidence: 99%

Forced axial segregation in axially inhomogeneous rotating systems

et al. 2015

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Controlling segregation is both a practical and a theoretical challenge. Using a novel drum design comprising concave and convex geometry, we explore, through the application of both discrete particle simulations and positron emission particle tracking, a means by which radial size segregation may be used to drive axial segregation, resulting in an order of magnitude increase in the rate of separation. The inhomogeneous drum geometry explored also allows the direction of axial segregation within a binary granular bed to be controlled, with a stable, two-band segregation pattern being reliably and reproducibly imposed on the bed for a variety of differing system parameters. This strong banding is observed to persist even in systems that are highly constrained in the axial direction, where such segregation would not normally occur. These findings, and the explanations provided of their underlying mechanisms, could lead to radical new designs for a broad range of particle processing applications but also may potentially prove useful for medical and microflow applications.

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“…The angle of repose of the particles next to the end wall is different to that in the bulk and particle motion in the axial direction accelerates, causing the formation of the segregation bands. Related reports focused on the influences of the end wall roughness on particle flow/segregation in rotating drums (Maneval et al, 2005;Arntz et al, 2013;Chand et al, 2012). End wall roughening increases the rate of axial segregation and reduces the particle near-wall transverse speed.…”

Section: Introductionmentioning

confidence: 99%

Controlling of Segregation in Rotating Drums by Independent End Wall Rotations

Kuo

Tseng

Huang

2016

KONA

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We present in this study that particle segregation in rotating drums can be controlled by end wall rotations. While the end wall rotational speed dominates the time required for reaching the steady state, the rotational direction of the end walls determines the segregation patterns and the shearing zone size. New segregation patterns with two well-mixed regions close to the end walls are observed in the drums with the end wall rotates in the direction opposite to the cylindrical wall. The end wall rotation causes the formation of the local valley and hill next to the wall. Particles flow into the valley and down the hill causing the formation of the convective flow cell at bed surface. It is the difference of the axial velocities between the large particles and small particles close to the end walls separating the particles of difference sizes in the axial direction. The controlling of the end wall roughness and rotating directions effectively enlarge the size of the end wall shearing zone; resulting segregation patterns which are different from the previous simple segregation band patterns.

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The influence of end walls on the segregation pattern in a horizontal rotating drum

Cited by 20 publications

References 29 publications

Time-resolved granular dynamics of a rotating drum in a slumping regime as revealed by speckle visibility spectroscopy

Time-resolved granular dynamics of a rotating drum in a slumping regime as revealed by speckle visibility spectroscopy

Forced axial segregation in axially inhomogeneous rotating systems

Controlling of Segregation in Rotating Drums by Independent End Wall Rotations

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