Numerical Study on Effect of Contact and Interfacial Resistance on Thermal Conductivity of Dispersed Composites

Abstract

A series of finite element analyses were conducted to clarify the effect of contact and interfacial resistance between constituents on effective thermal conductivities of dispersed composites. Equally dispersed fillers in FCC (face-centered cubic) and BCC (body-centered cubic) material systems were extracted from cyclic microstructures as unit cell models. In addition to spherical fillers, a polyhedron called the Wigner–Seitz cell that can realize a fully packed microstructure was chosen as the shape of the filler to investigate the effect of contact between the high volumetric fraction of fillers. The effective thermal conductivities of the resulting composites were calculated based on the FEA results and compared to the theoretical results for various volume fractions of the fillers including the maximum packing fraction. The following conclusions were obtained from the present study: 1. The effect of the contact depending on the shape and configuration of the fillers has more of a significant influence on the effective thermal conductivity than the influence of the increase in the volume fraction of the fillers. 2. When the contact occurred, the effective thermal conductivity became more than double that without contact. 3. Interfacial thermal resistance must be less than the order of 10−4 m2K/W to obtain improvement in the effective thermal conductivity by compounding the fillers.

Exploring the Impact of Visual Heat Conduction Paths on Thermal Conductivity of Polymer Composites and the Practical Applications

“…As illustrated in Figure , the heat conduction paths were formed by the thermally conductive fillers and polymer substrate. Because the thermal conductive fillers and POE are insulating, heat transfer in the heat conduction paths is achieved through phonon propagation. , The main factors hindering phonon propagation are the contact thermal resistance between the fillers and the interface thermal resistance between the filler and the substrate. , The reason for the higher thermal conductivity of the filler@1/2POE composite film compared to filler@POE is that the filler@1/2POE composite film has a more densely packed heat conduction network, enabling it to transfer heat more efficiently. Conversely, the lower thermal conductivity of the filler@1/4POE composite film compared to the filler@1/2POE composite film is attributed to an excessively dense heat conduction network in the filler@1/4POE composite film, which creates a significant amount of thermal resistance that hampers the efficient transfer of heat.…”