Thermal conductivity test and model modification of SiO2 aerogel composites based on heat flow meter method

Abstract

In the composition of thermal protection system, lightweight and efficient super thermal insulation materials-aerogel and its composites have been paid more and more attention and applied in recent years. The heat transfer of aerogel composites is more complicated due to the influence of micro-scale additives, fiber distribution and coupling heat transfer of various heat transfer modes, so it is urgent to calculate the effective thermal conductivity (ETC) accurately. According to the variation law of gas, solid, gas–solid coupling and radiation thermal conductivity with temperature and pressure, the thermal conductivity test is conducted based on the heat flow meter method, so as to the mathematical models of thermal conductivity are modified. The modified models take into account the influence of various micro-scale additives, which can accurately and quickly calculate the ETC of aerogel composites under different working conditions. The questions that different aerogel composites need to reconstruct structural models and the existing theoretical formulas are inaccurate in calculating ETC are solved. This paper is of great theoretical value to accurately predict the thermal insulation performance of aerogel composites.