Ellipsoidal Thermal Concentrator and Cloak with Transformation Media

Thermal concentrators and cloaks with ellipsoidal shapes are designed by utilizing the transformation thermotics method and finite element simulations. The thermal conductivities for the concentrator and cloak are directly derive in Cartesian coordinates. The simulation results show that the ellipsoidal thermal concentrator can focus heat flux into a central region and that the ellipsoidal thermal cloak can guide heat flux around the cloaked region smoothly without disturbing the external temperature distribution and heat flux. The present method can be extended to design arbitrarily shaped thermal metadevices with novel properties. (paper)