New models for thermal conductivity of particulate composites

Three new models for the effective thermal conductivity of concentrated particulate composites are developed using the differential effective medium approach. One model predicts the relative thermal conductivity (K-r) of a particulate composite to be a function of two variables, namely thermal conductivity ratio lambda (ratio of dispersed-phase to continuous-phase conductivities) and volume fraction of particles phi. The other two models predict K-r to be a function of three variables, namely, lambda, phi, and phi(m) where phi(m), is the maximum packing volume fraction of particles. The proposed models are evaluated using twelve sets of published experimental data on the thermal conductivity of particulate composites, covering broad ranges of lambda and phi.