The Effect of Particle Size on Thermal Conduction in Granular Mixtures

Materials

Junghwoon Lee²  Tae Sup Yun¹  Sung-Uk Choi¹ 

[1] Department of Civil and Environmental Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Korea; E-Mail:;Department of Civil and Environmental Engineering, Georgia Institute of Technology, North Ave NW, Atlanta, GA 30332, USA; E-Mail:

关键词: thermal conductivity;    rubber mixture;    size ratio;    discrete element method;    network model;   

DOI  :  10.3390/ma8073975

来源: mdpi

【 摘 要 】

Shredded rubber tire is a geomaterial that is potentially useful in environmental and engineering projects. Here, we study the effect of particle size ratio on the thermal conductivity of granular mixtures containing rubber tire particles. Glass beads were mixed at various volume fractions with rubber particles of varying size. The 3D network model analysis using synthetic packed assemblies was used to determine the dominant factors influencing the thermal conduction of the mixtures. Results present that mixtures with varying size ratios exhibit different nonlinear evolutions of thermal conductivity values with mixture fractions. In particular, mixtures with large insulating materials (e.g., rubber particles) have higher thermal conduction that those with small ones. This is because the larger insulating particles allow better interconnectivity among the conductive particles, thereby avoiding the interruption of the thermal conduction of the conductive particles. Similar tests conducted with natural sand corroborate the significant effect of the relative size of the insulating particles. The 3D network model identifies the heterogeneity of local and effective thermal conductivity and the influence of connectivity among conductive particles. A supplementary examination of electrical conductivity highlights the significance of local and long-range connectivity on conduction paths in granular mixtures.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.