THERMAL-DIFFUSION OF A 2-LAYER SYSTEM

Thermal conductivity and thermal diffusivity of a two-layer system are examined from the theoretical point of view. We use the one-dimensional heat-diffusion equation with the appropriate solution in each layer and boundary conditions at the interfaces to calculate the heat transport in this bounded system. We also consider the heat flux at the surface of the sample as a boundary condition instead of using a fixed temperature. From this, we obtain an expression for the effective thermal diffusivity of the composite sample in terms of the thermal diffusivity of its constituent materials without any approximations. © 1995 The American Physical Society.