Ultra High Temperature Thermal Insulation Materials and the Significance of Opacification in the Suppression of Radiative Transport

There is, nowadays, a large shift to high temperature operations in many applications such as industrial processes, power plants, and energy storage applications. Although some current thermal insulation materials show a good performance, they either don’t withstand high temperatures or have a high thermal conductivity at high temperatures. The aim of the present thesis is to develop a pathway to improve the performance of high temperature thermal insulation by suppression of radiative transport. For this purpose, two insulation designs have been investigated: multilayer insulation (MLI) design and volumetric extinction design. The results revealed that MLI design works best with metals. However, they will oxidize or, worse, melt at high temperatures which indicates the performance limitation of multilayer insulation design at high temperatures. On the contrary, the results showed that non-metals, as more stable materials at high temperatures, show a better performance to suppress radiation in the volumetric design.