Effect of particle angularity on flow regime transitions and segregation of bidisperse blends in a rotating drum

Beaulieu, Christine; Vidal, David; Niyonkuru, Carine; Wachs, Anthony; Chaouki, Jamal; Bertrand, François

doi:10.1007/s40571-021-00421-1

Cited by 10 publications

(6 citation statements)

References 54 publications

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“…This is due 170 to the onset of a segregation inversion in which large grains 171 begin to accumulate at the center of the drum (Supplemental 172 Materials). This result agrees with previous studies that found 173 inverse segregation for large size ratios, where depending on 174 the roughness of the walls and the weight of the grains, large 175 grains may condensate in the center of the drum (30,39,40). 176…”

Section: Grain Shape Controls On Segregation In a Dry Rotating Drumsupporting

confidence: 88%

“…42 Some previous studies have examined the role of grain shape in (5,(26)(27)(28). Grain shape has been shown to alter mobility in a variety of flow regimes, with sharp edges of cubes 48 dissipating energy faster than spheres and decreasing mobility 49 (28)(29)(30). However, findings from these studies are often seem-50 ingly conflicting and have been difficult to synthesize because…”

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confidence: 99%

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How particle shape affects granular segregation in industrial and geophysical flows

Cunez¹,

Patel²,

Glade³

2023

Preprint

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Industrial and environmental granular flows commonly exhibit a phenomenon known as ``granular segregation," in which grains separate according to physical characteristics (size, shape, density), interfering with industrial applications (cement mixing, medicine and food production) and fundamentally altering the behavior of geophysical flows (landslides, debris flows, pyroclastic flows, riverbeds). While size-induced segregation has been well studied, the role of grain shape is not well understood. Here we conduct numerical experiments to investigate how grain shape affects granular segregation due to grain-grain and grain-fluid interactions. To isolate the former, we compare dry, bidisperse mixtures of spheres alone with mixtures of spheres and cubes in a rotating drum. Results show that while segregation generally increases with particle size ratio, the presence of cubes decreases segregation levels compared to cases with only spheres. Further, we find hysteresis in segregation trends with size ratio; segregation is lowest when the small grains are cubic as they approach a jammed state with reduced mobility. We find similar hysteresis in simulations of a shear-driven coupled fluid-granular flow (e.g., a riverbed), demonstrating that this phenomenon is not unique to rotating drums; however, in contrast to the dry system, we find that total segregation increases in the presence of cubic grains, and fluid drag effects can qualitatively change segregation trends. Our findings demonstrate competing shape-induced segregation patterns in wet and dry flows—independently from grain size controls—with implications for many industrial and geophysical processes.

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Section: Grain Shape Controls On Segregation In a Dry Rotating Drumsupporting

confidence: 88%

mentioning

confidence: 99%

How particle shape affects granular segregation in industrial and geophysical flows

Cunez¹,

Patel²,

Glade³

2023

Preprint

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show abstract

“…Using this method, the details of each particle can be monitored . Extensive studies have previously been conducted to achieve many great results in terms of granular motion by using this method, and have tried to figure out many important mechanisms behind the motion, such as the effects of drum geometry or internals on the granular, , the flow regimes transitions in rotating drums, − the mechanism of mixing and segregation of a binary mixture or polydisperse mixtures in rotating drums, − etc. Most DEM codes used by those studies concentrated on spherical particles or assumed granules of spherical shape, which simplified the real process and reduced the computational cost.…”

Section: Introductionmentioning

confidence: 99%

SuperDEM Simulation and Experiment Validation of Nonspherical Particles Flows in a Rotating Drum

Cui

Dai

et al. 2023

Ind. Eng. Chem. Res.

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Understanding the flow behaviors of nonspherical particles is critical for rotating drum design and optimization. Rotating drum experiments of particles of different properties were conducted and the flow behavior was investigated by high-resolution camera recordings. The superquadric discrete element method (SuperDEM) was employed to simulate the spherical and nonspherical particle flows and validated by comparing the simulation results with the experimental data. A sensitivity study shows that angles of repose of spheres, cubes, and green beans were approximately constant when the friction coefficient was larger than 0.3, while for cylindrical shape particles, angles increased continuously until μ was 0.6. To study the impact of shapes, the validated model was applied to simulate particles of different shapes with the same density and volume. It was found that cylindrical particles with smaller sphericity had larger repose angles and were packed more densely than spheres, and the relationship between sphericity and angle was nonlinear. Nonspherical particles had a higher kinetic energy conversion efficiency, and cylinders’ and cubes’ average rotational kinetic energies were also larger than that for spheres. The ratio of the rotational kinetic energy to the total kinetic energy of cylinders was up to 10.59%, which indicated the significant impacts of particle shapes. Besides, particle shapes significantly affect the anisotropic distribution of the normal contact forces, especially for cylinders and cubes.

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“…Some previous studies have examined the role of grain shape in controlling rotating drum segregation patterns, showing that the presence of angular shapes can dissipate more rotational energy, affecting how grains interact with the wall and with each other ( 5 , 28 – 30 ). Grain shape has been shown to alter mobility in a variety of flow regimes, with sharp edges of cubes dissipating energy faster than spheres and decreasing mobility ( 30 – 32 ). However, findings from these studies are often seemingly conflicting and have been difficult to synthesize because it is nontrivial to disentangle the role of shape and size, and different filling levels and rotational speeds used in different studies can result in complex, unpredictable radial segregation patterns that are challenging to compare ( 4 , 31 – 36 ).…”

mentioning

confidence: 99%

“…Grain shape has been shown to alter mobility in a variety of flow regimes, with sharp edges of cubes dissipating energy faster than spheres and decreasing mobility ( 30 – 32 ). However, findings from these studies are often seemingly conflicting and have been difficult to synthesize because it is nontrivial to disentangle the role of shape and size, and different filling levels and rotational speeds used in different studies can result in complex, unpredictable radial segregation patterns that are challenging to compare ( 4 , 31 – 36 ). Only recently has a universal framework been proposed for segregation levels with different shapes; Jones et al ( 5 , 28 ) found that segregation levels for bidisperse grains (disks, rods, spheres) in a numerical model depends largely on the single-grain volume ratio between the two species rather than diameter ratio, which can be challenging to define for different shapes.…”

mentioning

confidence: 99%

How particle shape affects granular segregation in industrial and geophysical flows

Cúñez,

Patel,

Glade

2024

Proc. Natl. Acad. Sci. U.S.A.

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Industrial and environmental granular flows commonly exhibit a phenomenon known as “granular segregation,” in which grains separate according to physical characteristics (size, shape, density), interfering with industrial applications (cement mixing, medicine, and food production) and fundamentally altering the behavior of geophysical flows (landslides, debris flows, pyroclastic flows, riverbeds). While size-induced segregation has been well studied, the role of grain shape has not. Here we conduct numerical experiments to investigate how grain shape affects granular segregation in dry and wet flows. To isolate the former, we compare dry, bidisperse mixtures of spheres alone with mixtures of spheres and cubes in a rotating drum. Results show that while segregation level generally increases with particle size ratio, the presence of cubes decreases segregation levels compared to cases with only spheres. Further, we find differences in the segregation level depending on which shape makes up each size class, reflecting differences in mobility when smaller grains are cubic or spherical. We find similar dynamics in simulations of a shear-driven coupled fluid-granular flow (e.g., a simulated riverbed), demonstrating that this phenomenon is not unique to rotating drums; however, in contrast to the dry system, we find that the segregation level increases in the presence of cubic grains, and fluid drag effects can qualitatively change segregation trends. Our findings demonstrate competing shape-induced segregation patterns in wet and dry flows that are independent from grain size controls, with implications for many industrial and geophysical processes.

show abstract

Effect of particle angularity on flow regime transitions and segregation of bidisperse blends in a rotating drum

Cited by 10 publications

References 54 publications

How particle shape affects granular segregation in industrial and geophysical flows

How particle shape affects granular segregation in industrial and geophysical flows

SuperDEM Simulation and Experiment Validation of Nonspherical Particles Flows in a Rotating Drum

How particle shape affects granular segregation in industrial and geophysical flows

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