Computer simulation of the packing of fine particles

This paper presents a simulation study of the packing of uniform fine-spherical particles where the van der Waals force is dominant. It is shown that porosity increases with the decreases of particle size from about 100 to 1 &mgr;m and the simulated relationship can match the literature data well. The packing structure of fine particles is qualitatively depicted by illustrative pictures and quantified in terms of radial distribution function, angular distribution, and coordination number. The results indicate that in line with the increase in porosity, the first component of the split second peak and then the other peaks beyond the second one in the radial distribution function gradually vanish; the first peak becomes narrower, with a sharp decrease to the first minimum. As particle size decreases, the peaks at 120 degrees and then 60 degrees in the angular distribution will gradually vanish; the coordination number distribution shifts to the left and becomes narrower. The mean coordination number can decrease to a value as low as two for 1 &mgr;m particles, giving a very loose and chainlike structure. The interparticle forces acting on individual particles in a stable packing are analyzed and shown to be related to the packing properties.

[1]  J. L. Finney,et al.  Fine structure in randomly packed, dense clusters of hard spheres , 1976 .

[2]  W. Visscher,et al.  Random Packing of Equal and Unequal Spheres in Two and Three Dimensions , 1972, Nature.

[3]  S. Luding,et al.  Simulations of Dense Granular Flow: Dynamic Arches and Spin Organization , 1996 .

[4]  G. T. Nolan,et al.  Computer simulation of random packing of hard spheres , 1992 .

[5]  Hans J. Herrmann,et al.  Modeling granular media on the computer , 1998 .

[6]  J. L. Finney,et al.  Random packings and the structure of simple liquids. I. The geometry of random close packing , 1970, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[7]  P. Meakin,et al.  Structural readjustment effects in cluster-cluster aggregation , 1985 .

[8]  P. Cundall,et al.  A discrete numerical model for granular assemblies , 1979 .

[9]  E. M. Tory,et al.  Anisotropy in Simulated Random Packing of Equal Spheres , 1968, Nature.

[10]  Mehta,et al.  Vibrated powders: Structure, correlations, and dynamics. , 1992, Physical review. A, Atomic, molecular, and optical physics.

[11]  Charles H. Bennett,et al.  Serially Deposited Amorphous Aggregates of Hard Spheres , 1972 .

[12]  Paul Zulli,et al.  Evaluation of effective thermal conductivity from the structure of a packed bed , 1999 .

[13]  Wiley,et al.  Numerical simulation of the dense random packing of a binary mixture of hard spheres: Amorphous metals. , 1987, Physical review. B, Condensed matter.

[14]  Anand Jagota,et al.  Micromechanical modeling of powder compacts—I. Unit problems for sintering and traction induced deformation , 1988 .

[15]  A. J. Matheson.  Computation of a random packing of hard spheres , 1974 .

[16]  Aibing Yu,et al.  Numerical simulation of the gas-solid flow in a fluidized bed by combining discrete particle method with computational fluid dynamics , 1997 .

[17]  Z P Zhang,et al.  Effect of packing method on the randomness of disc packings , 1996 .

[18]  D. Caprion,et al.  Computer investigation of long-range correlations and local order in random packings of spheres. , 1996, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[19]  J. D. Bernal,et al.  A Geometrical Approach to the Structure Of Liquids , 1959, Nature.

[20]  W. Gray,et al.  Significance of the properties of materials in the packing of real spherical particles , 1961 .

[21]  M. J. Powell.  Distribution of near neighbours in randomly packed hard spheres , 1980 .

[22]  Colin Thornton,et al.  Numerical simulation of the impact fracture and fragmentation of agglomerates , 1996 .

[23]  E. M. Tory,et al.  Simulated random packing of equal spheres , 1973 .

[24]  Aibing Yu,et al.  A simulation study of the effects of dynamic variables on the packing of spheres , 2001 .

[25]  G. Jimbo,et al.  The Estimation of Packing Characteristics by Centrifugal Compaction of Ultrafine Particles , 1989 .

[26]  P. L. Spedding,et al.  SIMULATION OF PACKING DENSITY AND LIQUID FLOW IN FIXED BEDS , 1995 .

[27]  Aibing Yu,et al.  Prediction of the Porosity of Particle Mixtures , 1998 .

[28]  James G. Berryman,et al.  Random close packing of hard spheres and disks , 1983 .

[29]  H. Scott Fogler,et al.  Modeling flow in disordered packed beds from pore‐scale fluid mechanics , 1997 .

[30]  J. Finney,et al.  Modelling the structures of amorphous metals and alloys , 1977, Nature.

[31]  D. J. Adams,et al.  Computation of Dense Random Packings of Hard Spheres , 1972 .

[32]  Aibing Yu,et al.  Dynamic simulation of the centripetal packing of mono-sized spheres , 1999 .

[33]  G. D. Scott,et al.  Radial Distribution of the Random Close Packing of Equal Spheres , 1962, Nature.

[34]  S. Bryant,et al.  Quantification of Spatial Correlation in Porous Media and Its Effect on Mercury Porosimetry. , 1996, Journal of colloid and interface science.

[35]  P. A. Langston,et al.  Distinct element simulation of interstitial air effects in axially symmetric granular flows in hoppers , 1996 .

[36]  A. Yu,et al.  Rolling friction in the dynamic simulation of sandpile formation , 1999 .

[37]  Jodrey,et al.  Computer simulation of close random packing of equal spheres. , 1985, Physical review. A, General physics.

[38]  E. Liniger,et al.  Packing and Sintering of Two‐Dimensional Structures Made fro Bimodal Particle Size Distributions , 1987 .

[39]  Feng,et al.  Quantification of the Relationship between Porosity and Interparticle Forces for the Packing of Wet Uniform Spheres. , 2000, Journal of colloid and interface science.

[40]  John Bridgwater,et al.  On the modelling of the packing of fine particles , 1997 .

[41]  The structure of liquids , 1960 .

[42]  D. Boudreaux,et al.  Structrue simulation of transition‐metal‐metalloid glasses. III , 1977 .