高温热源特性对木粉阴燃传播特性影响

Effect of High Temperature Heat Source Characteristics on Smoldering Propagation Characteristics of Wood Powder

为了探究高温热源特性对阴燃传播的影响,本文基于高温氮化硅点火装置建立了阴燃传播速度实验测试平台,并以红棕木粉为实验材料,结合木粉的热重分析开展了不同引燃温度和时间作用下木粉阴燃传播特性实验研究,结果表明:在实验条件下,木粉堆在6种不同适宜热源引燃温度下所能达到的最高温度几乎一致约490℃,且三个热电偶位置距离阴燃初始点越近其升温到最高温度越慢;在640℃到675℃之间存在一个最佳热源热通量使木粉堆析出挥发分与内部氧气含量为适宜比例,且在这个比例下木粉阴燃初期的传播速度最快,约4.4×10^-2 cm/s;相同高温热源温度下,木分堆持续引燃时间越长,热源提供的总热量越大,阴燃初期的传播速度越快。所得结果可为木材加工企业防控阴燃火灾提供实验依据。

In order to explore the influence of high temperature heat source characteristics on smoldering propagation,this paper establishes a smoldering velocity experimental test platform based on high temperature silicon nitride ignition device,and uses red brown wood powder as experimental material.Combined with the thermo-gravimetric analysis of wood powder,an experimental study on the smoldering propagation characteristics of wood powder under different ignition temperatures and time was carried out.The results show that under the experimental conditions,the maximum temperature that the wood powder pile can reach under the ignition temperature of 6 different suitable heat sources is almost uniform at about 490℃.And the closer to the initial point of the smoldering,the slower it rises to the highest temperature;An optimum heat source heat flux between640℃and 675℃makes the wood powder heap volatiles and the internal oxygen content a suitable ratio,and at this ratio,the wood powder ash smoldering speed is the fastest,about 4.4×10^-2 cm/s;The longer the ignition time of the wood pile,the greater the total heat supplied by the heat source,and the faster the initial speed of the smoldering.The obtained results can provide experimental basis for wood processing enterprises to prevent and control smoldering fires.