Effects of thermal contact resistance and radiation on the effective thermal conductivity of composites

The derivation of effective thermal conductivity (ETC) for composites is a long-standing thermal transport problem. Based on thermal resistance model and integration method, two analytical solutions of the ETC of composites with spherical inclusions are derived. As the effect of thermal contact resistance on the inclusion surface is considered, the theoretical analysis shows that the dimensionless ETC of the composites increases with the increase of the dimensionless thermal conductivity of dispersed phase. Since the volume percentage of the contact section is very small in the unit cell, the effect of the thermal conductivity of contact section on the dimensionless ETC of the composites is weak. As the effect of radiation in porous composites is considered. The theoretical result indicates that the effect of radiation cannot be neglected as the temperature or porosity of composites is high. The differences between the theoretical results and experimental data of the ETC of porous composites are acceptable.