The thermal conductivity of aggregates of several phases, including porous materials

Expressions for the thermal conductivity of two-phase media are derived for various types of structure, and these are compared with the experimental results of Sugawara and Yoshizawa. The extension to the case of three phases is given. For porous media, such as sandstone, the structure plays a vital part in the determination of the thermal conductivity, and a model is proposed which allows this feature to be included and which provides a consistent explanation of experimental data.