Switching the Cloaking Effect of the Bilayer Thermal Cloak: On or Off

Abstract

Thermal cloaking refers to the phenomenon that an external heat flux can bypass a thermal cloaking device without affecting objects within the cloaking region of the device and the heat flux outside the cloak.  A bilayer thermal cloak model has been proposed by using bulk materials an inner layer with very low thermal conductivity (TC) and an outer layer with higher thermal conductivity (TC) to regulate the external heat flux, allowing for a thermal cloaking effect.  Usually, materials with temperature-dependent thermal conductivity are prevalent in nature.  However, previous studies have not thoroughly examined the impact of temperature on TC.  Therefore, it is crucial to consider the thermal conductivity's temperature dependence when designing thermal cloaks.  In this paper, we propose two types of switchable bilayer thermal cloaks based on materials with different types of temperature-dependent thermal conductivity, by which the cloaking effect could be in the off or on state in response to varying temperature. The cloaking performance of the switchable cloak is demonstrated based on numerical simulations.

Keywords: thermal cloaking, temperature-dependent thermal conductivity, bulk material