Modeling and Implementation of Multilayer Insulation for Small-Scale Ultrahigh Temperature Systems

Abstract

Thermal energy based portable electrical sources have garnered increasing attention from researchers, owing to their high efficiency, high energy density, and exceptional portability. The insulation of heat sources has a significant impact on the efficiency of power generation. However, the fabrication of small-scale multilayer insulation (MLI) remains a great challenge due to high temperature environment and materials compatibility. Here, microfabricated MLI insulators ranging from micron to millimeter scales have been successfully developed. The MLI model was developed by adopting near-field radiative heat transfer and the results were verified experimentally using micron-scale material made by refractory ceramic titanium nitride (TiN) sandwiched between silica aerogel. The performance was further compared with meso-scale MLI based on TiN and silica fiber films. Both micron-scale and meso-scale MLI materials have exhibited outstanding thermal insulation performance at 1400 K without structure degradation while retaining 78% and 88% of radiative heat, respectively. A further optimized micro-scale and meso-scale MLI materials were able to maintain 85% and 93% of thermal radiation at temperatures up to 1400 K. These findings unlock the further development of small-scale MLI materials for thermal insulation in thermalbased portable power generation.

Keywords: thermal energy, high temperature materials, meta-materials, thermal insulation