Non-silica fiber and enabled stratified fiber doping for high temperature aerogel insulation

Spherical opacifier doping aerogels for thermal insulation have been investigated in the past decades. However, the cylindrical fiber doping is seldom studied, in particular, there are no thermal analysis on non-silica fiber-loaded aerogels which can satisfy thermal insulation and mechanical requirements in harsh thermal environment simultaneously. The radiation inhibition property and overall insulation performance of non-silica fiber doping method are numerically investigated in the present work. Our results reveal that the optimal diameter of non-silica fiber dopant is significantly lower than that of opacifier doping at identical temperature. Carbon fiber has incomparable infrared radiation suppression ability of about 4 times that of carbon opacifier in the whole temperature range. Compared with the opacifier doping, the non-silica fiber doping method is demonstrated to provide stronger light shielding effect, lower thermal conductivity at a certain doping fraction, and much higher mechanical properties. Moreover, a stratified core-shell design for oxidizable carbon fiber is proposed to extend its excellent radiation suppression ability to high temperature. These findings provide useful guidance for the application of fiber-reinforced aerogels for high temperature thermal insulation.