A numerical and experimental study on thermal conductivity of particle filled polymer composites

In this study, thermal conductivity of particle filled polymer composites is investigated numerically and experimentally. In the numerical study, the finite-element program ANSYS is used to calculate the thermal conductivity of the composite by using the results of the thermal analysis. Three-dimensional models are used to simulate the microstructure of composite materials for various filler concentrations at various ratios of thermal conductivities of filler to matrix material. The models used to simulate particle filled composite materials are cubes in a cube lattice array and spheres in a cube lattice array. A modified hot wire method is used to measure the thermal conductivity of the composites consisting of a high-density polyethylene (HDPE) matrix filled with tin particles up to 16% by volume. The experimentally measured thermal conductivities are compared with numerically calculated ones by using the spheres in cube model and also with the already existing theoretical and empirical models. At low particle content, up to 10% of volume content of tin filler, numerical estimation and all other models except for the Cheng and Vachon model, predict well the thermal conductivity of the composite. For more heavily filled composites there is an exponential increase in thermal conductivity and most of the models fail to predict thermal conductivity in this region.