Thermal rectification mechanism of composite cylinders with temperature and stress-dependent interface thermal resistance

Abstract

Thermal rectifier behaves thermal rectification phenomenon if it exhibits asymmetric heat transfer characteristics along a given direction. The present paper established a theoretical model of the cylindrical thermal rectifier, and developed a Galerkin finite element method to numerically investigate the thermoelastic coupling response of the thermal rectifier. Initial interface gap is introduced here to manipulate the different contact statuses of the rectifier for forward and reverse cases to optimize the thermal rectification ratio. Temperature and stress-dependent interface thermal resistance as well as temperature-dependent thermophysical properties of the rectifier are considered in the analysis. Effects of initial interface gap, boundary conditions, geometry parameters and material pairs on thermal rectification ratio are given based on the numerical results. Results show that, the equivalent thermal conductance of the thermal rectifier is the key factor to optimize the thermal rectification ratio that can be utilized through different initial interface gaps, and the status switch of the interface gap for forward and reverse cases leads to the maximal thermal rectification ratio. The proposed numerical method as well as the thermal rectification mechanism could be guidance for the optimal design of the cylindrical thermal rectifier.