Experimental Investigations on the Thermal Conductivity of Silica Aerogels by a Guarded Thin-Film-Heater Method

A thin-film-heater method is setup to measure the thermal conductivity of super insulating materials such as silica aerogels. The experimental setup is purposely designed for insulating materials and allows direct measurement of the thermal conductivity. Few experimental data are available in the literature concerning thermal conductivity of aerogels even though these materials are of major interest in thermal insulation. More data are necessary in order to understand thermal transport and to validate existing models. Monolithic and granular silica aerogels are investigated. Our experimental technique enables to quantify the influence of important parameters, such as air pressure and distribution of grain sizes, on the insulating performance of this material.