Effective thermal conductivity of two-phase systems with cylindrical inclusions

A theoretical model is presented to predict effective thermal conductivity of real two-phase materials from the values of thermal conductivity of the constituent phases and their volume fractions. Two-phase materials have been assumed to contain cylindrical particles arranged in a regular three-dimensional cubic geometry. The arrangement has been divided into unit cells, each of which contains a cylinder. The resistor model has been applied to determine the effective thermal conductivity (ETC) of the unit cell. A porosity correction term F is introduced in order to incorporate varying individual geometries and nonlinear flow of heat flux lines generated by the difference in thermal conductivities of constituent phases. Theoretical calculations of the ETC have been carried out on a large number of samples and comparisons have been made with other models and experimental values cited in the literature. The values predicted by the proposed model are in close agreement with experimental values and more accurate than those obtained from existing models.