Design of hollow glass fiber/silica aerogel composites for high-temperature thermal insulation applications

•Design the geometric structure of hollow glass fiber/silica aerogel composites.•Develop an analytical model considering both heat conduction and thermal radiation.•Analyze the factors including hollowness, external diameter, and mass fraction. Pure silica aerogels are not suitable for high-temperature (500 ∼ 2000 K) thermal insulation applications due to their transparency to infrared thermal radiation. The addition of solid glass/ceramic fibers, such as aluminum oxide and silicon oxide, into the silica aerogel matrix can remarkably suppress the radiative heat transfer. However, the introduced solid fibers increase the structural density and enhance heat conduction in silica aerogel composites. Herein, we propose adopting hollow fibers (HFs) to simultaneously minimize thermal radiation and heat conduction through silica aerogels in a high-temperature environment. The results show that increasing fiber hollowness improves the short-wavelength (