金属热颗粒引燃可燃堆积材料的实验研究

Experimental study on the ignition of combustible bulk materials by a hot metal particle

电焊操作、烟花燃放、工业磨削和高压电线碰撞等过程容易产生高温热颗粒。这些热颗粒一旦接触可燃材料就有可能引燃材料,导致火灾。该文对热颗粒引燃可燃堆积材料的行为进行实验研究,从而为工业堆积材料的火灾防控方法提供参考。实验加热一系列不同直径(6mm,8mm,10mm,12mm,15mm,20mm)的黄铜金属颗粒作为热源,并采用三种常见的工业堆积材料(木粉,炭粉,羟丙基甲基纤维素HPMC)作为可燃材料的代表物,研究不同功率金属热颗粒对材料的引燃行为,分析金属热颗粒引燃材料的临界功率。结果表明,材料本身的性质会影响热颗粒的引燃行为,HPMC的引燃时间最长,木粉的引燃时间最短。随着热颗粒直径的增加,热颗粒引燃三种材料所需的功率值整体呈增大的趋势。由于燃烧空腔的形成,HPMC的引燃临界功率相对较高。

Welding process, firework display, industrial cutting, clashing of high voltage lines and other human activities and industrial processes, often produce hot metal particles. Once these hot particles land on the combustible bulk materials, the materials may be ignited and a fire may be initiated, which threatens the safety of industrial activities. This work studied the ignition behavior of combustible bulk materials by hot particles, in order to provide reliable guidelines for the fire prevention and detection of industrial bulk materials. A series of metal particles with diameters of 6, 8, 10, 12, 15 and 20 mm and three kinds of common bulk materials, wood powder, carbon powder and hydroxypropyl methyl cellulose （HPMC）, were used in the experiments. The ignition behavior of materials by hot particles with different heating power was studied to reveal the critical conditions for ignition. The results showed that the ignition behavior was affected by the material properties. Among these three materials, it takes much longer time to ignite HPMC than the others and much shorter time to ignite wood powder. Generally, the critical ignition powers of three materials increase with the increase of the particle diameter. The critical ignition powers of HPMC are much higher due to the formation of void during the combustion process.