Broadband high-temperature thermal emitter/absorber designed by the adjoint method

Abstract

Broadband thermal emitters/absorbers are of great interest for thermal management in high-temperature applications including thermophotovoltaics and hypersonics due to the dominance of radiative heat transfer. Several studies have been reported, which benefit from the effectiveness of photonic structures on wave coupling tuned by parametric sweeps and intuition. However, the higher emission/absorption potential of structures with nonintuitive geometries due to increased number of available design parameters has not been explored. To address this need, we have studied gradient-based topology optimization for the design of high-temperature thermal emitters/absorbers. By utilizing the adjoint method, which allows gradient calculation only with two simulations, more complex geometries that exhibit higher emission/absorption in the broadband spectrum are designed. Z r B 2 is chosen as the coating material, which belongs to the family of ultrahigh-temperature ceramics (UHTC), due to its very good thermomechanical properties. Emission/absorption rates reaching up to 85% levels in the broadband spectrum are achieved, which is around 40% levels in film form. Electromagnetic phenomena that give rise to elevated emission/absorption are also analyzed. Our findings demonstrate the potential of effectiveness of adjoint-based topology optimization in the broadband spectrum and high emission of Z r B 2 when patterned, which, to the best of our knowledge, was not previously explored.

Multi-material design optimization of optical properties of particulate products by discrete dipole approximation and sequential global programming

“…Furthermore, for the efficient inverse design of fluctuating thermal sources, based on a reformulation of a standard DDA approach, called thermal DDA (T-DDA) (Edalatpour and Francoeur 2014), an evolutionary lattice design approach was proposed in Salary and Mosallaei (2019). Manuscripts dealing with pixel-based design optimization in the context of electromagnetics using finite difference time domain (FDTD) approaches can be found, e.g., in Kecebas and Sendur (2021) and Yang et al (2021). However, most of the examples studied in the mentioned papers are twodimensional, and therefore, the computational complexity is significantly lower compared to the three-dimensional examples considered in this manuscript.…”