Effects of end wall friction in rotating cylinder granular flow experiments

Maneval, James E.; Hill, K. M.; Smith, Braunen E.; Caprihan, Arvind; Fukushima, Eiichi

doi:10.1007/s10035-005-0211-4

Cited by 57 publications

(33 citation statements)

References 8 publications

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“…[29,[32][33][34]. Using magnetic resonance imaging Maneval et al [29] also (again for D experiments in the rolling regime) found the curved streamlines and, additionally, measured particle fluxes in slices through the bed normal to the axis of rotation for both 2-dimensional and 3-dimensional tumblers. In their 2-d tumbler and in the middle of their 3-d tumbler the upward particle flux equaled the downward flux.…”

Section: Axial Segregation At the End Wallmentioning

confidence: 93%

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Experimental study of density segregation at end walls in a horizontal rotating cylinder saturated with fluid: friction to lubrication transition

et al. 2012

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What is the effect of interstitial fluid viscosity on granular density segregation in a horizontal rotating cylinder? We conducted experiments in the rolling regime with equal amounts of equal sized high and low density, nearly spherical granular particles saturated with air, water, and waterglycerin mixtures. We held particle density, rotation rate and characteristic length scale constant to highlight differences due purely to the interstitial fluid. Images of the granular flow at an end wall were used to determine radial and axial density segregation rates and patterns. Over a four decade change in viscosity, segregation rates varied by only a factor of two. However, for ratios of lubrication to frictional stresses above one, segregation rates decreased by about 30%, and we observed several notable phenomena in the segregation pattern formation. These were a creeping mode of radial density segregation, a change in shape of the granular bed to kidney shaped from flat, and for cylinders more than half full the Electronic supplementary material The online version of this article (typically reported unsheared central portion of the granular bed (often referred to in the literature as a core region) was disrupted by a wavy instability where the rate of disappearance of the core region decreased as the fill level increased.

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Section: Axial Segregation At the End Wallmentioning

confidence: 93%

“…is the area, which grows with time t, in the viewing plane of the black particles within A i , then [28,29]. However, in 3-dimensional tumblers axial segregation fluxes may occur, and F w may not equal F b .…”

Section: Image Processingmentioning

confidence: 95%

Experimental study of density segregation at end walls in a horizontal rotating cylinder saturated with fluid: friction to lubrication transition

et al. 2012

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“…The quasi-2D approach cannot avoid wall effects, while the MRI does not suffer of this limitation. We believe this to be a crucial point: even if is commonly accepted that there is a strong influence of the lateral wall on the flow [8][9][10][11][12][13], most of the experiments are performed in the worst condition, i.e. by looking at grains near the wall.…”

Section: Experimental Evidences In the Rolling Regimementioning

confidence: 96%

Flow of Dry Grains Inside Rotating Drums

Monaco

Greco

Maffettone

2014

Challenges in Mechanics of Time-Dependent Materials, Volume 2

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In proper ranges of operating conditions, granular materials inside rotating drums display a continuum motion near their free surface. The motion of those discrete systems was studied both experimentally and through Discrete Element Method (DEM) numerical simulations. However, it can be regarded as the flow of a continuum medium, thus allowing a continuum mechanics approach. In our work, we solve the continuum dynamic equations by adopting the visco-plastic JFP constitutive model Jop et al. (Nature 441:727-730, 2006) for the stress tensor, and study the continuous flow of dry grains inside axially rotating cylinders through both 2D and 3D finite volume simulations (FVM). Our preliminary results are in qualitative agreement with some experimental data previously published. In contrast with the solid and gaseous behaviors, for which advanced theoretical frameworks exist, the theory for dense liquid regime is still at a rather early stage of development. Many observed phenomena and main features of liquid-like granular flows are still only tentatively described theoretically; we mention, as examples:• The presence of a yield criterion: the flow is only possible beyond a critical shear stress; • The complex dependence of flow response on the flow rate; • The strong dependence on geometric factors, such as size and shape of the particles and geometric details of the flow.The above mentioned theoretical approaches to dense liquid-like granular flows are based on direct numerical simulations of the grain system or on descriptions at the continuum mechanics level. For the latter case, of interest here, a constitutive equation for the stress tensor of granular media has been recently proposed [4] and tested in some simple geometries and/or flow conditions. Complex flow situations, on the other hand, have not been systematically tackled within this approach, and the present paper is a novel contribution in this direction.Among complex granular material flows, one of the most interesting is the flow inside a cylinder rotating about its axis, the so called "rotating drum" problem. This kind of flow has been largely investigated in literature, in part also due to its

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“…Small particles are wrapped by large particles in the radial direction after several revolutions by the particle percolation mechanism and balancing between the centrifugal and the gravitational forces. Alternative small-particle-rich and large-particle-rich bands in the axial direction are then observed later at the bed surface (Turner and Nakagawa, 2000;Maneval et al, 2005;Alizadeh et al, 2013). Comparing to the level of comprehension of the radial segregation cores, our knowledge to the axial segregation bands is poor.…”

Section: Introductionmentioning

confidence: 99%

“…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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Effects of end wall friction in rotating cylinder granular flow experiments

Cited by 57 publications

References 8 publications

Experimental study of density segregation at end walls in a horizontal rotating cylinder saturated with fluid: friction to lubrication transition

Experimental study of density segregation at end walls in a horizontal rotating cylinder saturated with fluid: friction to lubrication transition

Flow of Dry Grains Inside Rotating Drums

Controlling of Segregation in Rotating Drums by Independent End Wall Rotations

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