Controlling heat capacity in a thermal concentrator using metamaterials: Numerical and experimental studies

We developed two thermal concentrators, one with a 2D design of uniform thickness and another with a 3D design, using the coordinate transformation technique and metamaterials. By structuring the thermal conductor, we were able to achieve the desired local density-heat capacity product rho C and anisotropic thermal conductivities. Homogenized thermal conductivities were obtained from the boundary heat fluxes of the unit cells computed with finite element simulations and taking into account the cylindrical symmetry. We fabricated the 3D concentrator using 3D metal printing and used a thermal camera for characterization. By designing the unit cells to obtain the (rho C) values given by the coordinate transformation, the time evolution characteristics of the metadevice are closer to those of an ideal concentrator when compared to devices that solely consider anisotropic conductivities.

Automated summary

This study developed two thermal concentrators, one with a 2D design of uniform thickness and another with a 3D design, using the coordinate transformation technique and metamaterials. By structuring the thermal conductor, the desired local density-heat capacity product and anisotropic thermal conductivities were achieved. The homogenized thermal conductivities were obtained from finite element simulations and cylindrical symmetry consideration. A 3D concentrator was fabricated using 3D metal printing and characterized using a thermal camera. Compared to devices that solely consider anisotropic conductivities, the time evolution characteristics of the metadevice designed with coordinate transformation were closer to those of an ideal concentrator.