Time prediction of burn injury was performed aiming at lasting fire exposure, and the performance of the parameters of thermal protective clothing was investigated. The modeling and simulation method was used to predict the longest safety work time for the burn different degrees. Firstly, for the system of three-layer fabric materials ( composed of an outer shell, a moisture barrier and a thermal liner) , body skin and the air gap between the clothing and the skin, an improved heat transfer model together with boudary/initial conditions was presented in high temperature environments. Secondly, the presented model was applied to calculate the temperature on the fixed contact surface changing with time, and the numerical results were compared with the existing model under the same condition to verify the credibility of the model. Finally,the developed model was also used to predict the critical time to first-/second-/third-degree burn injury and to analyze the influence of air gap and textile thickness on the performance of thermal protective clothing. It is found that under the flash fire condition, the firefighters only have a dozen seconds to escape even wearing protective clothing, and the thicknesses of the air gap and the fabric have a significent influence on the performance of the clothing.%针对人体持续暴露在闪火环境中烧伤时间及热防护服参数对防护性能的影响情况,利用建模与模拟的方法预测达到各级烧伤的最长安全工作时间.首先,对包含外壳、防水层和隔热层的3层防火材料、皮肤及三者间的空气层组成的系统,给出了系统各层热传递微分方程以及初边值条件,改进了已有的高温条件下多层热防护服的热传递模型.接着,使用该模型计算出各固定接触面随时间变化的温度值,该计算结果与同等条件下已有模型一致,从而验证了模型的可靠性.最后,采用改进的模型预测达到一级、二级和三级烧伤所需的临界时间,分析了空气层和织物厚度对防护服防护性能的影响.研究发现,在闪火条件下,消防人员即使身穿热防护服也仅有十几秒的安全时间,且空气层和织物的厚度大小对防服性能的影响十分显著.
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