Chapter 4 - Thermal metamaterials

Abstract

Light-weight, high-strength metamaterials with excellent heat dissipation and energy absorption capabilities are of great interest for aerospace and automobile applications. In particular, innovative structure design and its successful realization are paramount but often challenging due to the vast design space and associated complex manufacturing. In this chapter, inspired by pomelo peel's superior shielding protection of its pulp, bionic polyhedron metamaterials (BPMs) that imitate pomelo peel were designed and realized by metal 3D printing to achieve not only superior heat dissipation but also high energy absorption. Guided by experiments and numerical simulations, a BPM with circular struts has the highest Nusselt number and the lowest pressure drop and friction factor at Re=7000–30,000. Our results led to the conclusion that a BPM with circular struts exhibited a higher thermal efficiency index that exceeds 1 at 0.92 porosity. Furthermore, a BPM with circular struts possesses moderate specific energy absorption in existing mechanical metamaterials due to their corresponding density, which has potential for gas turbines and some cooling structures. The findings within this chapter will guide the design of metamaterials with high heat dissipation and energy absorption.