Measuring the flowing properties of powders and grains

Lumay, Geoffroy; Boschini, Frèdéric; Traina, Karl; Bontempi, Sébastien; Remy, Jean; Cloots, Rudi; Vandewalle, Nicolas

doi:10.1016/j.powtec.2012.02.015

Cited by 303 publications

(244 citation statements)

References 44 publications

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“…For many powders, cohesive effects are influenced by other forces besides capillary, such as van der Waals forces, electrostatic or magnetic forces, mechanical interlocking between particles, and combinations of these (McGlinchey, 2005), which lead to flow dynamics different from those observed for moisture-induced cohesion (Alexander et al, 2006;Li et al, 2011;Lumay et al, 2012;Tomas, 2004). In the cohesionless case, it is well known that as the drum rotational speed increases, the granular flow takes on one of a number of regimes such as slumping, rolling, cascading, cataracting, and centrifuging.…”

Section: Inroductionmentioning

confidence: 99%

“…In particular, the angle of repose is difficult to measure because of the irregular surface of the flow and the continuous regime does not exist. Indeed, the cohesion induces intermittencies over the whole range of rotational speeds (Alexander et al, 2006;Lumay et al, 2012), and limits the effectiveness of popular imaging techniques. Davies et al (2002) introduced a load cell device for sensing the motion of particulate material in a rotating cylinder by tracking changes in the centre of gravity of the particle bed, and subsequently demonstrated (Davies et al, 2004) that a load cell could be used to identify the initiation of an avalanche and to track its movement.…”

Section: Inroductionmentioning

confidence: 99%

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Granular dynamics of cohesive powders in a rotating drum as revealed by speckle visibility spectroscopy and synchronous measurement of forces due to avalanching

Yang

Jiang

Saw

et al. 2016

Chemical Engineering Science

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We have used speckle visibility spectroscopy (SVS) and synchronized force measurements to compare the granular dynamics of two cohesive lactose powders, with Sauter mean diameters of ~29 μm and ~151 μm, in a rotating drum. A load cell (LC) was used to measure forces on the drum mounting frame and enable monitoring of bulk powder motion; SVS is a dynamic light scattering technique particularly suited for studying dynamics in dense, non-ergodic granular systems. Our results reveal that surface slumping and intermittent collisional dynamics in the bulk of the bed are correlated, especially for the fine more cohesive particles (Geldart group C/A boundary), but not as much for the less cohesive larger particles (Geldart group A/B boundary). The specific dissipation energy of the particles in the drum is similar for both powders, and increases linearly with increasing drum speed. However, the dependencies of the load cell and SVS signals on rotation speed have opposing trends for these two powders, indicating different dissipation mechanisms for the different Geldart Groups; collisional dissipation is more important for the Geldart C/A powder, while for the Geldart A/B powder avalanche dissipation is dominant.

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Section: Inroductionmentioning

confidence: 99%

Section: Inroductionmentioning

confidence: 99%

Granular dynamics of cohesive powders in a rotating drum as revealed by speckle visibility spectroscopy and synchronous measurement of forces due to avalanching

Yang

Jiang

Saw

et al. 2016

Chemical Engineering Science

View full text Add to dashboard Cite

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“…We have developed a protocol and an automated device [18] to perform an accurate measurement of the behavior of a granular material submitted to a series of taps. The measurement is done in a tube.…”

Section: Experimental Set-upmentioning

confidence: 99%

“…Different methods can be used to obtain both η ∞ and τ. To obtain more informations about these methods, see the references [18,16].…”

Section: Experimental Set-upmentioning

confidence: 99%

Influence of cohesive forces on the macroscopic properties of granular assemblies

Lumay¹,

Fiscina²,

Ludewig³

et al. 2013

AIP Conference Proceedings

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Abstract. The influence of cohesive forces inside a granular material is analyzed with compaction experiments. To begin, a model cohesive granular material is considered. This granular material is made of millimetric grains with a cohesion induced by an external magnetic field. Therefore, the cohesion between the grains is adjusted through the intensity of the applied magnetic field. Afterward, the cohesion induced by capillary bridges are considered. In the first study concerning capillary forces, the cohesion between neighboring grains is induced by liquid bridges in a wet granular material. The cohesiveness is tuned using different liquids having specific surface tension values. The second study performed with capillary forces concerns initially dry granular materials surrounded by a well controlled air humidity. Then, the cohesion inside the packing is controlled through the relative humidity which influence both triboelectric and capillary effects. The evolution of the parameters extracted from the compaction curves have been analyzed as a function of the cohesiveness. All the results show that the packing fraction of a pile and the compaction dynamics is strongly sensitive to cohesive forces. Therefore, the compaction measurement is a good way to characterize a powder or a granular material for R&D and quality control in industrial applications. Finally, we show that the cohesive forces play an important role when the grain size is typically below 50μm.

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“…Many tests, both experimental and computational, have used spheres or cylinders due to the simplicity of those shapes [1] with glass beads often chosen for fundamental experiments. There have been studies conducted on systems entirely consisting of irregularly shaped or elongated particles [2][3][4][5], as well as the influence of mixtures of regular and elongated particles [6]. The behaviour of a single elongated free flowing intruder within a 2D layer of spheres has also been studied [7].…”

Section: Introductionmentioning

confidence: 99%

The behaviour of free-flowing granular intruders

et al. 2017

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Abstract. Particle shape affects both the quasi-static and dynamic behaviour of granular media. There has been significant research devoted to the flowability of systems of irregularly shaped particles, as well as the flow of grains around fixed intruders, however the behaviour of free flowing intruders within granular flows remains comparatively unexplored. Here, the effect of the shape of these intruder particles is studied, looking at the kinematic behaviour of the intruders and in particular their tendency of orientation. Experiments are carried out within the Stadium Shear Device, which is a novel apparatus able to continuously apply simple shear conditions to two-dimensional grain analogues. It is found that the intruder shows different behaviour to that of the bulk flow, and that this behaviour is strongly shape dependent. These insights could lead to the development of admixtures that alter the flowability of granular materials.

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Measuring the flowing properties of powders and grains

Cited by 303 publications

References 44 publications

Granular dynamics of cohesive powders in a rotating drum as revealed by speckle visibility spectroscopy and synchronous measurement of forces due to avalanching

Granular dynamics of cohesive powders in a rotating drum as revealed by speckle visibility spectroscopy and synchronous measurement of forces due to avalanching

Influence of cohesive forces on the macroscopic properties of granular assemblies

The behaviour of free-flowing granular intruders

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