436377 Numerical and Experimental Study on the Packing Densification of Cubic-Spherical Particle Mixtures Under One-Dimensional Vibration

Wednesday, November 11, 2015: 2:30 PM
254C (Salt Palace Convention Center)
Haidong Feng, University of Utah, Salt Lake City, UT and Sanja Miskovic, Metallurgical Engineering, University of Utah, Salt Lake CIty, UT

Dense packing of heterogeneous particle mixtures is a common phenomenon occurring in nature and many industrial processes. For example, packing density and packing dynamics determine the efficiency of sintering, powder injection molding, and pneumatic transporting processes. Previous research work has mainly been focused on the packing dynamics of perfect spherical particles. On the other hand, it is only recently that packing densification of non-spherical heterogeneous particle mixtures has become a focus of research interest. In this work, the packing dynamics of binary mixtures of spherical and non-spherical particles is studied both numerically and experimentally. The packing densification of binary cubic-spherical particle mixtures under one-dimensional (1D) vibrations of various frequencies is evaluated and reported through this work. The commercial software EDEM, a powerful discrete element method (DEM) based numerical tool with significant computing capacity and good accuracy, is used through the numerical study. Results obtained through this comprehensive DEM analysis allowed a detailed characterization of bulk and local properties of different particle beds. The particle packing density is simulated and packing structure is studied by the particle coordination number. Furthermore, the effect of various process parameters, namely particle size, fractional volume of large particles, vibration frequency, and packing column diameter, on packing densification is investigated. The obtained numerical results are verified experimentally on four different packing columns of diameters 109.9, 140.38, 185.77, and 229.7 mm using seven different fractional volumes of large particles, namely 0%, 20%, 50%, 60%, 70%, 80%, and 100%. Both numerical and experimental results indicate that 1D vibration can be used to realize the transition of particle packing condition from random loose packing (RLP) to random close packing (RCP) of all investigated particle beds. For the condition when the fractional volume of large particles is 70% and small to large equivalent packing diameter ratio is 0.139, it is found that the maximum packing density reaches 0.84, which is higher than the maximum packing density reported for the equivalent binary spherical mixture.

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