Tunable control of extremely concentrated heat flux through a thermal manipulator

It is crucial to effectively control the heat flux in thermal functional devices and electronic systems. Here, we numerically simulate and experimentally design a simple but effective thermal manipulator based on transformation thermodynamics, which is capable of realizing an extreme heat flux concentration in a small area and guiding the heat flux to the region we desired. The experimental results show that the thermal manipulator has compressed the heat flux from the line-shaped thermal source with an extremely high concentration efficiency of 91.1% and a region concentration ratio of 39.7. The temperature gradient in the small area is 4.42 K/mm, which is about 115% of the applied temperature gradient, indicating a very strong heat concentration capability. Furthermore, the thermal manipulator can physically rotate the heat flux under a constant temperature gradient through a diagonal thermal conduction vector as well. By concentrating and deflecting the heat flux, the extreme concentration and tunable control of the heat flux have been demonstrated, providing an effective thermal manipulating method for the heat flux control in the small area.