Topology-optimized thermal metamaterials based on inhomogeneous and anisotropic unit array

In this paper, inhomogeneous and anisotropic thermal metamaterials are designed to achieve the manipulation of heat flow (MHF) at multiple points. The thermal metamaterial unit is constructed from mixtures of two solidstate materials with different thermal conductivities. A variable density topology optimization method is employed to design the filling fractions of the mixed materials within the unit. The thermal concentrator and cloak are designed through the optimization of the topological functional units (TFUs). The thermal gradients of 14 and 0.05 times the uniform thermal gradient are achieved by the concentrator and the cloak, respectively. The effectiveness of the proposed design method is validated through the excellent agreement between numerical simulations and experimental results.