The modeling of transverse solids motion in rotary kilns

Henein, H.; Brimacombe, J. K.; Watkinson, A. P.

doi:10.1007/bf02661017

Cited by 126 publications

(64 citation statements)

References 10 publications

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“…Therefore, our result suggests that the particles experience around two avalanches on average as they travel from the top to the bottom of the drum. This is in line with the PEPT study of Lim et al [11] but at odds with the Table I. single avalanche assumption in the models of Henein et al [9] and others [3,10]. Figure 6(c) shows that the particle fluctuation speed of the avalanches, δv 2 p , for points A and B are normally distributed also, but the averages are very different.…”

Section: Resultssupporting

confidence: 84%

“…Combining this observation with the relation of t r suggested by the model of Henein [9] leads to observation that the difference in the upper and lower angles of repose, θ , decreases linearly with increasing rotational speed.…”

Section: Discussionmentioning

confidence: 63%

“…They are, however, not without their problems. The models of Henein et al [9] and other related models [3,10] for predicting the slumping and rolling transitions, for example, assume the grains fall from wedge OAB to OA B in Fig. 1 in a single avalanche.…”

Section: Introductionmentioning

confidence: 99%

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Avalanche dynamics of granular materials under the slumping regime in a rotating drum as revealed by speckle visibility spectroscopy

Yang

Kong³

et al. 2015

Phys. Rev. E

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Section: Resultssupporting

confidence: 84%

Section: Discussionmentioning

confidence: 63%

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Avalanche dynamics of granular materials under the slumping regime in a rotating drum as revealed by speckle visibility spectroscopy

Yang

Kong³

et al. 2015

Phys. Rev. E

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“…The volumes of the mixtures were scaled by identical percentage fills to be comparable between the two 102 different drums as proposed by Henein et al (1983b). Our goal was to use a volume of material that created 103 flows significantly thicker than the maximum grain diameter, but minimized the infilling of the drum to reduce 104 bed curvature effects.…”

mentioning

confidence: 99%

Frictional behavior of granular gravel–ice mixtures in vertically rotating drum experiments and implications for rock–ice avalanches

Schneider

Kaitna

Dietrich

et al. 2011

Cold Regions Science and Technology

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Rapid mass movements involving large proportions of ice and snow can travel significantly further downslope than pure rock avalanches and may transform into debris-flows as the ice melts and as water from the stream network or water-saturated debris is incorporated. Currently, ice is thought to have three distinctive effects: 1) reduction of the friction within the moving mass itself, 2) increase of pore pressure as the ice melts and consequent reduction of the shear resistance of the flowing material, and 3) reduction of boundary friction where the failing mass travels on a glacier. However, measurement-based evidence to support these hypotheses is largely missing. In this study, laboratory experiments on the first two mechanisms were carried out in two partially-filled large rotating drums, one in Vienna (Austria) and a second in Berkeley (USA). Varying proportions of cold gravel and gravel-sized ice were mixed and added to the rotating drum running at constant rotational velocity until all ice had melted. Flow behavior was recorded with flow depth, normal force, shear force, pore-water pressure, and temperature sensors. The bulk friction coefficient was found to decrease linearly with increasing ice content by ~ 20% in the early phase of the experiments, before significant portions of the ice transformed into water. For ice contents larger than 40% by volume, the transformation from a dry granular flow to debris-flow-like movement or hyperconcentrated flow was observed when pore-water pressures rose and approached the normal forces along the flow profile. Pore-water pressure from melting ice developed within several minutes after the start of the experiments and, as it increased, progressively reduced the friction coefficient. The results emphasize that the presence of ice in granular moving material can significantly reduce the friction coefficient of both dry and partially-saturated debris. Due to size effects and the absence of other factors reducing friction (e.g. surfaces with low friction and rock comminution), the absolute measured friction coefficients from the laboratory experiments were larger than those found from natural events. However, the relative changes in friction coefficients depending on the ice and water content may also be considered in real-scale hazard assessments of rapid mass movements in high mountain environments. coefficients from the laboratory experiments were larger than those found from natural events. However, the 31 relative changes in friction coefficients depending on the ice and water content may also be considered in real-32 scale hazard assessments of rapid mass movements in high mountain environments. 33

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“…Finally, the scaling laws of the system are discussed and numerical results support our conclusions. Among all the geometries used to study granular flows, the rotating drum might be the most complex [1,2,3]. Depending on the angular velocities, two different regimes occur.…”

mentioning

confidence: 99%

Sshape of a granular pile in a rotating drum

2006

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The shape of a granular pile in a rotating drum is investigated. Using Discrete Elements Method (DEM) simulations we show that the "S shape" obtained for high rotation speed can be accounted for by the friction on the end plates. A theoretical model which accounts for the effect of the end plates is presented and the equation of the shape of the free surface is derived. The model reveals a dimensionless number which quantifies the influence of the end plates on the shape of the pile. Finally, the scaling laws of the system are discussed and numerical results support our conclusions.

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The modeling of transverse solids motion in rotary kilns

Cited by 126 publications

References 10 publications

Avalanche dynamics of granular materials under the slumping regime in a rotating drum as revealed by speckle visibility spectroscopy

Avalanche dynamics of granular materials under the slumping regime in a rotating drum as revealed by speckle visibility spectroscopy

Frictional behavior of granular gravel–ice mixtures in vertically rotating drum experiments and implications for rock–ice avalanches

Sshape of a granular pile in a rotating drum

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