Transformed thermal meta-devices for manipulating macroscopic thermal fields

The thermal problems closely related to the development of human life, scientific technology and engineering production are greatly influenced by the thermal properties of carrier media, while most traditional natural substances are incompetent to achieve the flexible and diverse on-demand thermal control that is increasingly needed. Stimulated by materials science and physics, the combination of thermal metamaterial (artificial composite with peculiar thermalphyscial properties) and transformation thermotics (theoretical method of pre-designing heat distribution at will) has promoted heat transfer research enter a novel phase. Aiming at macroscopic heat transfer that is one of the most fundamental cases in thermal science and directly affects various thermal management and thermal rectification problems, in this review, we retrace the progress of transformed thermal meta-devices for manipulating macroscopic thermal field from the various aspects combining theoretical calculation, numerical simulation and experimental verification. Apart from the devices containing single field manipulation function or applicable to single thermal field, we further take a look at multifunctional transformed thermal meta-devices including devices that suitable for different physical fields and containing various forms of thermal field manipulation. Moreover, we review the explorations of practical application of transformed thermal meta-devices. Finally, we point out some limitations and challenges together with potential future directions in this fascinating area.