Thermal diode with switchable cloaking effect enabled by asymmetric temperature-dependent thermal conductivity

Thermal rectification refers to the asymmetry in heat transfer capability when subjected to forward and reverse temperature gradients. A thermal cloak can render objects invisible in thermal fields by redirecting heat flux pathways. In this paper, we present a thermal diode model based on a bi-layer thermal cloak system that incorporates a composite heat-flux-attracting layer with asymmetric, temperature-dependent thermal conductivity. In the forward case, the heat flux bypasses the cloaking region while maintaining undistorted background isotherm contours, whereas in the reverse case, the thermal cloak fails to function and the device effectively insulates heat. Consequently, thermal rectification occurs in the bi-layer thermal cloak system. A significant increase in the thermal rectification ratio is observed as the temperature gradient increases. By optimizing the system dimensions, a peak rectification ratio of 11.06 is achieved. This study provides physical insight and a design framework for developing novel thermal diodes with dual-functional thermal management capabilities.