通风对居住舱火灾初期探测影响的数值研究

Numerical Study on the Influence of Ventilation upon the Initial Fire Detection of Accommodation Cabin

为深入掌握居住舱内发生火灾时不同的强制通风方式对火灾初期探测所带来的影响,利用数值方法对一居住舱内4种典型通风方式下的火灾初期热流场进行模拟,对舱室火灾探测器所在位置处的温度和烟气浓度进行分析。研究发现,火灾初期舱室内热流场分布受通风方式影响明显,通风不仅可以阻碍火灾初期阶段热烟气在舱室顶棚的快速积累,而且可使烟羽流撞击舱室顶棚位置发生横向偏移,使火灾探测器适合的安装位置发生改变,为实现火灾发生后更短时间内即能发现火情而发出报警信号,在进行火灾早期快速探测报警系统工程设计过程应与舱室实际通风充分相结合。针对舱室顶棚中心处的固定式点型探测器,侧送侧回的通风方式对实现火灾早期快速探测影响相对较小,且火灾探测器适宜安装在距离舱室顶棚下约0.1 m高度范围内。

In order to understand the impact of different forced ventilation methods on the initial fire detection when a fire occurs in the accommodation cabin,numerical methods were used to simulate the heat flow field of an accommodation cabin under four typical ventilation methods at the initial stage of the fire.The temperature and smoke concentration at the location of the cabin fire detector were analyzed.It was found that the ventilation slowed down the rise rate of temperature and smoke concentration in the center of the cabin ceiling,and had a certain lag effect on fire detection in the early stage immediately after the fire.Also,the side-feed and side-return ventilation method has relatively little influence,and the fire detector is suitable to be installed at about 0.1 m below the ceiling of the cabin.