Thermal conductivity of tubular nanowire composites based on a thermodynamical model

• Heat transfer in tubular nanowire composites is studied.
• The model is based on Extended Irreversible Thermodynamics.
• Results agree with solutions from Boltzmann's equation.
• Temperature effect on heat conductivity is emphasized.

A formula for the effective heat conductivity of a nanocomposite with cylindrical nanowire inclusions is derived. Both transversal and longitudinal heating along the wires are investigated. Several effects are examined: the volume fraction and sizes of the nanowires, the type of scattering at the particle-matrix interface and temperature. As illustration, silicon nanowires inclusions in a germanium matrix is considered; the results are shown to be in good agreement with other models and numerical solutions of the Boltzmann transport equation. Our main contribution consists of using extended irreversible thermodynamics to cope with the nano dimensions of the wires.