老化时间对聚乙烯导线火蔓延及滴落行为的影响研究  

Effect of aging time on fire spread and dripping behavior of polyethylene wire

作　　者：张英[1] 吴凌立 张波[2] ZHANG Ying;Wu Lingli;Zhang Bo(School of Safety Science and Emergency Management,Wuhan University of Technology,Wuhan 430070,China;School of Resources and Environmental Engineering,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学安全科学与应急管理学院,武汉430070 [2]武汉理工大学资源与环境工程学院,武汉430070

出　　处：《清华大学学报（自然科学版）》2024年第12期2177-2184,共8页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金面上项目(52074202)。

摘　　要：为研究老化聚乙烯导线火灾特性的影响规律,该文开展了不同老化时间下聚乙烯导线火蔓延特性实验研究,探讨不同老化时间对聚乙烯导线火蔓延行为的影响规律,包括火蔓延行为和滴落行为。实验结果表明,火焰高度、宽度和火蔓延速度随着老化时间的增加而降低,聚乙烯导线熔融滴落物的滴落频率和滴落质量随着老化时间的增加而降低,单液滴的质量随着老化时间的增加而增加。结合实验结果和理论分析得到了老化对聚乙烯导线火蔓延行为特性的影响规律。[Objective] To investigate the impact of thermal aging on the fire propagation characteristics of conductors,the fire propagation characteristics of conductors under different equivalent aging ages were experimentally studied.The effects of different equivalent aging years on the fire propagation behavior of polyethylene wire,including the spread and dripping behavior,were studied.[Methods] First,the service life of the expected test wire in an actual scene was derived from the empirical formula of the aging model investigated in previous studies,and the required test conditions were accordingly calculated.[Results]The experimental results show that with the extension of thermal aging time,the flame height,width,and spread speed decrease.During the equivalent aging time,the frequency and mass of the droplets in the melt decreased with increasing equivalent aging time,whereas the mass of individual droplets increased with increasing equivalent aging time.According to the experimental results and theoretical analysis,a thermal aging law for the wire fire propagation characteristics was established.An analysis of the effect mechanism of thermal aging on fire spread behavior reveals that an increase in the equivalent aging age mainly affects the change in the elongation at break and melting point of the thermal insulation layer.With the increase in the equivalent aging time,the elongation at break of the polyethylene insulation layer decreases,which affects the increase in the surface tension of the layer.Under the influence of high temperature,the melting speed of the solid insulation layer was accelerated,and the layer can more easily transition into a liquid state.The liquid melt on the upper surface of the insulation layer flows down the surface under the action of gravity.Once the self-gravity of the accumulated molten material overcomes the constraint of its surface tension,individual droplets are formed for dripping,and this dynamic constraint process becomes longer as the equivalent aging age increases.This r

关 键 词：老化 断裂伸长率 聚乙烯导线 火蔓延行为 滴落行为 

分 类 号：TD752.2[矿业工程—矿井通风与安全]