多孔型石英 ? 料 热脱水特性的研

This paper constructs a numerical model for coupled heat-moisture transfer during high-temperature dehydration to eliminate the influences of dehydration on the wave-transmitting performance of porous moisturized quartz composites. The influences of key parameters on the dehydration process are analyzed, and the distributions of material temperature, moisture content and dielectric loss during heat dehydration are obtained. Specifically a numerical model for high temperature dehydration of porous quartz composite is established an experiment is carried out according to the cup method stipulated in the standard ISO 12572: 2016 to obtain the key parameter vapor resistance coefficient of the model. At the same time, the high temperature heating test of porous quartz composites is designed and carried out, which verified the reliability of the numerical model. Based on the established numerical model, the influences of the heating temperature, the initial moisture content and the vapor resistance coefficient on the heat and moisture transfer and wave transmission performance of porous quartz composites are investigated in practical application. The variations of the internal temperature, the volumetric moisture content and the dielectric loss with heating time under different working conditions are analyzed. The results show that higher heating temperature and lower initial moisture content are beneficial to the removal of moisture in porous quartz composites. The increase of vapor resistance coefficient can obviously inhibit the gaseous water escape. Specifically, the dehydration rate of materials heated at 523 K is about 3 times that at 423 K. The dehydration time under 303 K and 90% relative humidity(saturated hygroscopic condition)is about twice that under 303 K and 30% relative humidity. When the vapor resistance coefficient is less than 200, the influence on the high temperature dehydration process is limited. Therefore, the aircraft should be treated with external coatings to reduce its moisture absorption in the actual storage process, and should fully speed up in the low-altitude flight stage to increase the temperature and time of aerodynamic heating, thus quickly removing moisture and reducing the influence of moisture on radio communication during high-altitude flight. The research results can provide guidance for the practical application of the porous quartz composites.