Finite element modeling of thermal conduction in spherical Al2O3 based composite materials

In conventional finite element simulations of heat transfer in polydisperse spherical Al 2 O 3 grains (SAG)/silicone rubber systems, a single median particle size has commonly been adopted for simplification. The simplified modeling approach that neglected particle size distribution effect, which led to markable inaccuracies in thermal transport predictions. To overcome this limitation, a three-dimensional stochastic distribution model of SAG/silicone rubber composites was developed in this manuscript. The relationships among the particle size distribution, volume fraction, and three-dimensional thermal conduction network of SAG with respect to the thermal performance of the composites were comprehensively analyzed. At a volume fraction of 45 vol% SAG, the effective thermal conductivity remained nearly unchanged despite variations in the particle size distribution of SAG. At 60 vol% SAG, the effective thermal conductivity increased significantly, and a distinct dependence on the particle size distribution was identified. Three-dimensional thermal conduction networks were constructed, incorporating variations in both particle size distribution and volume fraction. Quantitative analysis based on contact number and contact distance revealed that the contact distance played a critical role in governing thermal transport in SAG/silicone rubber composites.