热辐射下织物内水分干燥实验及其动力学研究

Drying experiment and kinetics of wetted fabrics exposed to thermal radiation

为研究低热流辐射环境下织物内的水分传递特征,借助红外成像仪及干燥理论方法分析了织物内部水分蒸发过程以及水分蒸发对织物隔热性能的影响。结果表明干燥过程可分为3个阶段:在加热阶段,织物干燥速率和温度快速提高,水分含量缓慢降低;在中间阶段,织物干燥速率保持稳定,温度缓慢升高,水分含量快速下降;在最后阶段,织物干燥速率降低,水分含量缓慢减少。含水率较高的织物其隔热性能较好,但含水率低于20%时,其隔热性能快速下降,致使织物表面温度快速上升。通过拟合水分干燥速率等数据,采用Page、Newton及Henderson3种经典干燥动力学模型,分析了织物水分扩散机制。结果显示,Page模型比较适合于描述低辐射热下织物内水分的动态干燥过程。

In order to investigate the moisture transfer characteristics of moisture in fabrics in low-level radiant heat exposures,the evaporation process of moisture in fabrics and the influence of moisture evaporation on the thermal insulation performance of fabrics were analyzed by using drying theoretical method and thermal infrared imager. The results indicate that the drying process of fabric can be divided into three stages： the initial heating stage,in which drying velocity and the temperature increase rapidly and the moisture content decreases slowly; the intermediate stage,in which the drying velocity keeps stable and the temperature increases slowly,while the moisture content decreases rapidly; and the final stage,in which the drying velocity slows down and the moisture content decreases slowly. The fabrics with higher moisture has better thermal insulation performance,but when the moisture content is lower than 20%,the thermal insulation performance decreases rapidly,causing rapid increase of the surface temperature of the fabric surface. The migration of moisture in fabrics was analyzed by fitting data such as moisture drying velocity,three classic drying kinetics models including Page,Newton and Henderson were adopted to analyze the migration of moisture in fabrics. The results show that the dynamic drying process of fabrics in low-level radiant heat exposures can be described mathematically by Page equation.