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以棉花仓库消防安全为背景,在火灾探测标准燃烧室内开展了棉花垛早期阴燃特性试验和吸气式复合探测试验研究。分析棉花垛早期阴燃过程中的质量损失、烟气浓度以及图像特征变化,以棉花垛顶部着火为例,归纳了阴燃过程大致包括水平蔓延及竖直蔓延两个阶段,并分析了各阶段特性。利用吸气式复合烟气诊断,分别记录了吸气管道出口的CO体积分数变化以及吸气式探测器的输出信号。结果表明,CO的响应时间明显快于吸气式探测器且几乎不受采样孔位置的影响。由于阴燃温度低,羽流湍浮力相对较弱,而CO气体密度远小于烟颗粒密度,在吸气管道中表现出更好的迁移性。因此,针对大空间棉储仓库,可以采用吸气式感烟火灾探测器与CO气体探测器相结合的复合探测手段,也可以考虑在传统吸气式探测器内部整合CO探测部件以提高探测报警速度,同时有效降低误报、漏报率。
Taking the fire safety of cotton warehouse as the background, the experiment of smoldering combustibility and aspirating composite detection of cotton stacks was carried out in the fire detection standard combustion chamber. Analysis of mass loss, flue gas concentration and image feature changes in the early smoldering process of cotton stacks, taking the top of the cotton stack as an example, the smoldering process generally includes two stages of horizontal spread and vertical spread, and analyzes various stages characteristic. The diagnosis of aspirating compound flue gas was used to record changes in CO volume fraction at the outlet of the aspiration tube and the output signal of the aspirating probe respectively. The results show that the response time of CO is obviously faster than that of aspirating detector and it is hardly influenced by the position of sampling hole. Due to the low smoldering temperature, plume buoyancy forces are relatively weak, whereas the CO gas density is much less than the smoke particle density and shows better mobility in the suction duct. Therefore, for large space cotton storage warehouse, you can use the combination of aspirating smoke detectors and CO gas detectors combined detection means can also be considered within the traditional aspirating detector integrated CO detection components to improve the detection alarm Speed, while reducing false positives, false negatives.