Rolling friction measurement of slightly non-spherical particles using direct experiments and image analysis

Agarwal, Amit; Tripathi, Aman; Kumar, Vimod; Chakrabarty, Arijit; Nag, Samik

doi:10.1007/s10035-021-01124-3

Cited by 3 publications

(11 citation statements)

References 20 publications

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“…The angle of repose was seen to increase with this coefficient in a non-linear fashion; the increase was greatest when the values for the coefficient were smaller. In a previous work, the authors determined the coefficient of friction for these pellets on a metallic base, but this was experimentally re-determined for the present work since the metal sample was different, and a value for μp-w of 0.2 was obtained [30]. When this value was used in the numerical simulations, the angle of repose obtained was 23.7° ± 0.9°, quite similar to the 24.1° ± 0.7° obtained experimentally with the metallic base.…”

Section: Numerical Simulationsmentioning

confidence: 99%

“…Unlike that seen with irregularly shaped particles, the cylindrical shape of pellets, which share two planes of symmetry with spheres, means that the coefficient of rolling friction has a significant influence on the frictional phenomena that occur within the stored material [29]. There are several ways-largely based on the use of inclined planes-in which this variable can be determined experimentally [30]. However, these experiments can be difficult to perform and only provide realistic values for virtually spherical particles.…”

Section: Introductionmentioning

confidence: 99%

“…However, these experiments can be difficult to perform and only provide realistic values for virtually spherical particles. Agarwal et al [30] reported that the distortion of the results from reality increases significantly as particles become less spherical. Thus, the coefficient of rolling friction is usually obtained via an indirect calibration procedure after experimentally obtaining the material's angle of repose, plus a comparison with that obtained via simulations involving the discrete elements technique [31].…”

Section: Introductionmentioning

confidence: 99%

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Determination of the Angle of Repose and Coefficient of Rolling Friction for Wood Pellets

et al. 2022

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The determination of the angle of repose for granular materials is indispensable for their handling and the design of containers and technological processing equipment. On the other hand, computational simulations have become an essential tool to understand the micro-behavior of the granular material and to relate it with the macro-behavior. The experimental determination of the angle of repose has a fundamental role when defining the required parameters to perform realistic simulations. However, there is a lack of a standard that allows the reproducibility of the experiments when using granular materials of equivalent spherical radius greater than 2 mm, such as corn, soybeans, wheat and PLA pellets, among others. In particular, a product of growing importance in the global strategy of decarbonization of the economy is biomass pellets, whose handling operations are one of the main components for the total cost of pellets supplied to the final user. In the present work, with the aim of determining the rolling friction coefficient, the variations in the angle of repose with the drop height for biomass pellets were studied both experimentally and with simulations, and an optimal procedure for its determination was found. Then, a calibration of the coefficient of rolling friction was performed through computational simulations using the discrete element method. The accuracy of the model under different configurations was checked.

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Section: Numerical Simulationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Determination of the Angle of Repose and Coefficient of Rolling Friction for Wood Pellets

et al. 2022

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“…It is even more difficult for crushed particles with irregular shapes which require even more statistics. It is common in granular media to determine μ r by letting a particle roll over a slope (Agarwal et al 2021). But the determination of μ r by this method can be very complicated or nearly impossible for small particles or particles with a large deviation from spherical shape.…”

Section: Characterising Quantities Of Particle Shapementioning

confidence: 99%

“…We use h ij to denote the height of the centroid G above the segment V i V j . The black point E ij is on the bisector of the segment V i V j and at the same height h ij from the segment V i V j as G. The eccentricity of the particle/polygon related to its side V i V j is defined as the ratio of the length of the vector e ij , denoted |e ij |, to the projected diameter, d. method introduced by Agarwal et al (2021) and Tripathi et al (2021), based on image analysis of static grains to calculate the rolling friction coefficient without considering any material properties of the particle. The basic principle of this novel method is to approximate the projected image of a given particle as a polygon that we can characterise by measuring:…”

Section: Characterising Quantities Of Particle Shapementioning

confidence: 99%

The role of rolling resistance in the rheology of wizarding quidditch ball suspensions

d'Ambrosio,

Koch,

Hormozi

2023

J. Fluid Mech.

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To elucidate the effect of particle shape on the rheology of a dense, viscous suspension of frictional, non-Brownian particles, experimental measurements are presented for suspensions of polystyrene particles with different shapes in the same solvent. The first suspension is made of spheres whereas the particles which compose the second suspension are globular but with flattened faces. We present results from steady shear and shear-reversal rheological experiments for the two suspensions over a wide range of stresses in the viscous regime. Notably, we show that the rheology of the two suspensions is characterised by a shear-thinning behaviour, which is stronger in the case of the suspension of globular particles. Since the shear-reversal experiments indicate an absence of adhesive particle interactions, we attribute the shear thinning to a sliding friction coefficient which varies with stress as has been observed previously for systems similar to the first suspension. We observe that the viscosity of the two suspensions is similar at high shear stress where small sliding friction facilitates particle relative motion due to sliding. At lower shear stress, however, the sliding friction is expected to increase and the particle relative motion would be associated with rolling. The globular particles attain a higher viscosity at low shear stress than the spherical particles. We attribute this difference to a shape-induced resistance to particle rolling that is enhanced by the flattened faces. Image analysis is employed to identify features of the particle geometry that contribute to the resistance to rolling. It is shown that the apparent rolling friction coefficients inferred from the rheology are intermediate between the apparent dynamic and static rolling friction coefficients predicted on the basis of the image analysis. All three rolling resistance estimates are larger for the globular particles with flat faces than for the spherical particles and we argue that this difference yields the stronger shear thinning of the globular particle suspension.

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Characterisation of binary mixtures of pellets and sinter for DEM simulations

Chakrabarty

Biswas

Basu

et al. 2022

Advanced Powder Technology

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Rolling friction measurement of slightly non-spherical particles using direct experiments and image analysis

Cited by 3 publications

References 20 publications

Determination of the Angle of Repose and Coefficient of Rolling Friction for Wood Pellets

Determination of the Angle of Repose and Coefficient of Rolling Friction for Wood Pellets

The role of rolling resistance in the rheology of wizarding quidditch ball suspensions

Characterisation of binary mixtures of pellets and sinter for DEM simulations

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