Evaluation of the packing characteristics of mono-sized non-spherical particles

Zou, Ruiping; Yu, Aibing

doi:10.1016/0032-5910(96)03106-3

Cited by 295 publications

(152 citation statements)

References 17 publications

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“…For example, in [26], the maximum of packing fraction is reached for α = 1.63 and is 12% above the dense random packing packing fraction for spheres. Such a behaviour has also been observed for particles shapes like cylinders or disks [34]. Concerning the average coordination number, the isocounting conjecture predicts that it should be equal to 10 for spheroids and 12 for general ellipsoids.…”

Section: Introductionmentioning

confidence: 84%

Dynamic Numerical Investigation of Random Packing for Spherical and Nonconvex Particles

2009

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Abstract. We simulate the sedimentation in a parallelepipedic container of spheres and nonconvex particles constituted by two overlapping spheres. We use the self-written code SCoPI. Thanks to an efficient handling of contacts between particles, it allowed us to consider up to 100, 000 spheres and 10, 000 nonconvex particles. The packing fraction (in bulk and close to a wall) as well as the mean value and the distribution of contacts of the final packings are reported. The results obtained for the classical case of spherical particles (packing fraction: 63.7%, mean number of contacts: 6) are in agreement with previous studies and validate the algorithm. The packing fraction for nonconvex particles increases and then decreases with respect to the aspect ratio, which is similar to the ellipsoid (convex) case. The number of contacts is different from the number of neighbours, which is of course never the case for spherical particles (convex particles). The number of contacts is discontinuous when slightly increasing the aspect ratio from the spherical case: it is equal to 6 in the spherical case and to 10 in the nonconvex case. These values correspond to the isocounting values, i.e. the number of contacts is twice the number of degrees of freedom. This contrasts with the ellipsoid case, where it sharply but continuously increases. Concerning the number of neighbours, it continuously increases for small aspect ratio (which is similar to the convex particle case), but decreases for higher aspect ratio.Résumé. Nous simulons la sédimentation dans un récipient parallélépipédique de sphères et de particules non convexes formées de deux sphères se chevauchant. Afin de réaliser ces simulations, de nouvelles fonctionnalités ontété ajoutées au logiciel SCoPI initialement développé par A. Lefebvre-Lepot. Grâcè a une prise en compte efficace des contacts, il nous a permis de considérer jusqu'à 100, 000 sphères et 10, 000 particules non convexes. La compacité (en volume et près d'une paroi), ainsi que la valeur moyenne et la distribution du nombre de contacts des configurations finales sont décrites. Les résultats obtenus dans le cas classique de particules sphériques (compacité de 63.7%, nombre moyen de contacts de 6) sont en accord avec de précédentesétudes et permettent de valider l'algorithme. La compacité pour les particules non convexes augmente puis diminue en fonction du rapport d'aspect, ce qui est similaire au cas (convexe) des ellipsoïdes. Le nombre de contacts est différent du nombre de voisins, ce qui bien entendu n'est jamais le cas pour des sphères (particules convexes). Le nombre de contacts est discontinu lorsque l'on augmente légèrement le rapport d'aspectà partir d'une sphère: il estégal a 6 dans le cas sphérique età 10 dans le cas non convexe. Ces valeurs correspondent aux valeurs isostatiques, c'està dire que le nombre de contacts estégal au double du nombre de degrés de liberté. Ce résultat diffère du cas des ellipsoïdes où il augmente fortement mais continûment. Quant au nombre de voisins, il augmente con...

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Section: Introductionmentioning

confidence: 84%

Dynamic Numerical Investigation of Random Packing for Spherical and Nonconvex Particles

2009

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“…Miyajima [23] showed that the change in void volume fraction of packed powder beds can be estimated, but it might be necessary to apply [100 taps to reach a more or less stable situation depending on particle shape. The dependence of HR on particle shape was also approved by Zou and Yu [24]. They showed that for large non-cohesive non-spherical powders HR decreased with an increase in sphericity.…”

Section: Hausner Ratio Hrmentioning

confidence: 98%

Powder flowability characterisation methodology for powder-bed-based metal additive manufacturing

et al. 2015

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Key in powder-bed-based additive manufacturing is the use of appropriate powder materials that fit to the process conditions. There are many parameters affecting the build process and the corresponding quality of the parts being built. Therefore, an accurate assessment of the powders becomes important. Such an assessment involves, besides others, the powder flowability, which should be sufficient in order to create good-quality powder layers. The current study aims at the development of suitable parameters and values for the qualification of metal powders for selective laser melting (SLM) with regard to their flowability. The powder flowability is assessed by the statistical analysis of the measured powder avalanche angles and the powder surface fractal, which give valuable information about the significance of inter-particle forces. A set of 21 different Fe-and Ni-based powders has been analysed and good correlations between the powder avalanche angles, the surface fractal and the particle shape with the optically evaluated flowability could be derived. The method allows a quantitative powder flowability assessment, which correlates with the experiences for powders for powder-bed-based additive manufacturing, especially for SLM.

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“…The porosity of particle binary mixtures of spheres with different sizes depends on the fractional content, x D , of spheres with larger diameter, D, and on the mono-size components porosities and particle size ratio between them [15].…”

Section: Introductionmentioning

confidence: 99%

Permeability and effective thermal conductivity of bisized porous media

Dias

Fernandes

Мота

et al. 2007

International Journal of Heat and Mass Transfer

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In the region of minimum porosity of particulate binary mixtures, heat exchange and permeability were found to be higher than the ones obtained with a mono-size packing built with the same small size particles used in the binary packing. This effect was noticed in the range of the particles size ratio 0.1-1.0.The obtained improvement on thermal performance is related to the increase of effective thermal conductivity (ETC) in the binary packing and to the increase in transversal thermal dispersion due to the porosity decrease and tortuosity increase.Permeability can increase by a factor of two, if the size ratio between small and large spheres of a loose packing stays in the range 0.3-0.5.

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Evaluation of the packing characteristics of mono-sized non-spherical particles

Cited by 295 publications

References 17 publications

Dynamic Numerical Investigation of Random Packing for Spherical and Nonconvex Particles

Dynamic Numerical Investigation of Random Packing for Spherical and Nonconvex Particles

Powder flowability characterisation methodology for powder-bed-based metal additive manufacturing

Permeability and effective thermal conductivity of bisized porous media

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