Zhai Chunjie,Zhang Siyu,Zhang Minxia,et al.Mechanism Analysis of Pyrolysis and Ignition of Translucent Combustible Under Time-Variant Heat Flux[J].Journal of Combustion Science and Technology,2020,(04):294-300.[doi:10.11715/rskxjs.R201906017]
变热流下透明可燃物热解着火的影响机理分析
- Title:
- Mechanism Analysis of Pyrolysis and Ignition of Translucent Combustible Under Time-Variant Heat Flux
- 文章编号:
- 1006-8740(2020)04-0294-07
- 分类号:
- X954
- 文献标志码:
- A
- 摘要:
- 着火时间是可燃物热解着火过程的重要特征参数．辐射热流直接影响可燃物的着火时间，为了简化解析求解，前人往往认为辐射热流为恒定常数且不进入样件内部，但火灾发生早期，透明可燃物接收到的辐射热流可能是随着时间上升的变化热流．针对此问题，本文以适用于变化辐射热流的透明可燃物热解数值和解析模型为基础，系统研究了辐射热流上升速度、表面吸收、内部吸收等因素对着火时间的影响，比较了两种模型的结果差异并探讨了环境与物性参数对解析模型准确性的影响．结果表明：在上升热流早期，解析法与数值法求解结果符合较好，随着热流与表面温度增加，表面对流换热、辐射、热解等因素开始作用，导致解析与数值结果出现偏差，需根据此偏差修正给定可燃物着火时间解析预测结果．
- Abstract:
- Ignition time is an important factor in the pyrolysis and ignition of combustibles. Radiant heat flux affects the ignition time of combustibles directly. In order to simplify the solution，the previous work was usually based on the assumption of constant heat flux and surface absorption. But the heat flux usually increases in a real fire and enters the translucent sample. To address this problem，both numerical and analytical models for a translucent solid under time-variant heat flux were developed. The influences of increasing speed of heat flux pyrolysis，heat losses，and surface absorption on ignition time were systematically studied. The influence of different parameters on the accuracy of analytical solution was also investigated. Results show that the analytical result agrees well with the numerical one in the early stage of fire，but the deviation increases with the increase of surface temperature and heat flux due to the influence of surface heat loss and pyrolysis. The accuracy of analytical result can be further improved by taking account of the deviation that depends on the increasing speed of heat flux.
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备注/Memo
收稿日期：2019-07-28．基金项目：国家自然科学基金资助项目(31872705)；2019 年江苏高校“青蓝工程”优秀青年骨干教师培养资助项目；南京森林警察学院预研项目(LGY201801，LGY201702)．作者简介：翟春婕（1988— ），女，博士，讲师.通信作者：翟春婕，113212@nfpc.edu.cn.