Transient heat transfer characteristic of silica aerogel insulating material considering its endothermic reaction

摘要

In the current work, we present an experimental study to investigate the reaction mechanism of silica aerogel material at high temperature. The experimental study is based on simultaneous thermal analyzer 449F3 as well as Fourier Transform Infrared Spectroscopy(FTIR). The results show that when the material is exposed at high temperature, the mass of material will decrease about 1.98% accompanying with endothermic effect. Via FTIR analysis, it is found that the mass loss of material may be caused by the removal of adsorbed water. Besides the experimental study, a numerical heat transfer model is constructed to study the transient heat transfer characteristic of aerogel material by taking the endothermic reaction into account. The numerical heat transfer model is validated by a classical Stefan problem and a corresponding experimental measurement. Afterwards, a parametric study is conducted to investigate the effect of two parameters, reaction temperature and reaction heat, on transient heat transfer characteristics of aerogel insulating material. The results show that:(1)Before reaching the reaction temperature T_(reaction), the material that with lower T_(reaction)possesses lower temperature. However, when it exceeds the reaction temperature, the material shows the highest temperature among other materials.(2)With the increase of reaction heat, the increasing trend of temperature is weakened and the emergent of the turning point that separates the temperature platform and temperature-rise period appears later.