NUMERICAL-CALCULATIONS OF THE THERMAL-CONDUCTIVITIES OF COMPOSITES - A 2-D MODEL

A 2-D numerical finite-difference model has been developed to calculat e the thermal conductivity of a composite material. The method is gene ral in that the distribution of components within the material can be ordered or random. Results from the calculations are compared with tho se based on a geometric model in which the conductivity of the composi te depends on the volume fractions of the different components and wit h conductivities calculated using real-space renormalization group the ory (RSRG) and the effective medium approximation (EMA). The results f rom the present work compare well with the geometric model and the EMA , whereas the RSRG results generally indicate lower conductivities. Po ssible reasons for the differences between the RSRG theory and the oth er methods are discussed.