棉花仓库火灾早期蔓延扩散研究

Study on fire spread at the early stage of cotton warehouse fire

基于PyroSim构建棉花仓库火灾动态数值模型,选取I型棉包为研究对象,分5个工况研究棉花仓库早期火灾蔓延程度。引入异向等距点的概念,在固定仓库体积、建筑平面利用系数及棉垛间隔的情况下,研究仓库尺寸对火灾早期烟气扩散的影响。异向等距点温度差震荡波动大小与仓库的长宽比成正比,异向等距点温差值与不同区域冷空气量差值的绝对值也成正比。为提高火灾预警信息准确度,缩短不同方向上探测器的报警间隔时间,基于研究结果建议棉包入库后应尽量保障棉花仓库内冷空气量均衡分布,根据异向等距点的温差优化探测器的安装位置。

Based on PyroSim, the fire dynamic numerical model of the cotton warehouse was established. With type I stacked cotton bale as research object, the fire spread at the early stage in cotton warehouse was simulated by 5 scenarios. The concept of isometric point was introduced, and the influence of warehouse size on smoke diffusion in early stage of fire was researched under the condition of fixed warehouse volume, utilization factor of buildingplane and cotton stack interval. The fluctuation of temperature difference between isometric points is proportional to the lengthwidth ratio of warehouse. The temperature difference of isometric points is also proportional to the absolute value of the difference of cold air volume in different regions. In order to improve the accuracy of fire warning information and shorten the alarm interval time of detectors in different directions, and based on the research results, it is suggested that the balance distribution of cold air in cotton warehouse should be guaranteed as far as possible after the bales are stored in the warehouse, the installation position of detector should be optimized according to temperature difference of isometric points.