Packing properties of binary mixtures in disordered sphere systems--颗粒学报PARTICUOLOGY

Meng, L., Lu, P., & Li, S. (2014). Packing properties of binary mixtures in disordered sphere systems. Particuology, 16, 155–166. https://doi.org/10.1016/j.partic.2014.02.010

Packing properties of binary mixtures in disordered sphere systems

Lingyi Meng, Peng Lu, Shuixiang Li^*

Department of Mechanics & Aerospace Engineering, College of Engineering, Peking University, Beijing 100871, China

10.1016/j.partic.2014.02.010

Volume 16, October 2014, Pages 155-166

Received 20 November 2013, Revised 28 January 2014, Accepted 26 February 2014, Available online 28 June 2014.

E-mail: lsx@pku.edu.cn

Highlights

• A complete profile of packing properties for binary sphere mixtures is presented.

• The effects of size ratio and volume fraction on binary mixtures are investigated.

• The radial distribution function and contact analysis are presented in detail.

• A new method to estimate the excluded volume is presented.

• The method could be extended to polydisperse mixtures in disordered sphere systems.

Abstract

Mixtures of binary spheres are numerically simulated using a relaxation algorithm to investigate the effects of volume fraction and size ratio. A complete profile of the packing properties of binary spheres is given. The density curve with respect to the volume fraction has a triangular shape with a peak at 70% large spheres. The density of the mixture increases with the size ratio, but the growth becomes slow in the case of a large size disparity. The volume fraction and size ratio effects are reflected in the height and movement, respectively, of specific peaks in the radial distribution functions. The structure of the mixture is further analyzed in terms of contact types, and the mean coordination number is demonstrated to be primarily affected by “large–small” contacts. A novel method for estimating the average relative excluded volume for binary spheres by weighting the percentages of contact types is proposed and extended to polydisperse packings of certain size distributions. The method can be applied to explain the density trends of polydisperse mixtures in disordered sphere systems.

Graphical abstract

Keywords

Disordered packing; Binary spheres; Volume fraction; Size ratio

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