Design via topology optimisation and experimental assessment of thermal metadevices for conductive heat flux shielding in transient regime

Abstract

The design via density-based topology optimisation (TO) of thermal metadevices for conductive heat flux manipulation in transient regime is introduced in this work. Such approach consists in the solution of a TO problem conceived to achieve simple devices of feasible manufacture, which are made of two macroscopically distinguishable isotropic materials of highly contrasting thermal properties. The objective function to be minimised during the solution of such TO problem is defined as the error in achieving a prescribed behaviour of the conductive heat flux in the region intended for its manipulation, and the well-known solid isotropic material with penalisation (SIMP) technique is used to define the material distribution as a continuous function. The finite element method is used for the numerical analysis of the metadevices performance, and for each finite element there is a single microparameter (artificial density) determining the material from which it is made. The proposed approach has been particularly applied to the design of metadevices to shield the conductive heat flux in a given region during a transient heat conduction process. Although the so-designed metadevices are made of standard isotropic materials, they actually behave as metamaterials allowing the desired manipulation of the heat flux. Such approach has been implemented in the design of an easy-to-manufacture metadevice capable of fulfilling the assigned task better than other design merely based on intuition, whose material distribution was conceived to at least roughly emulate the heterogeneous effective properties dictated by the method of transformation thermodynamics. Since the microparameters directly define the distribution of both isotropic materials, it has also been possible to manufacture a metadevice designed under the proposed approach and to experimentally evaluate its performance.