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为研究人防工程内走廊通道的坡度对烟气扩散的影响,运用火灾软件FDS建立一个长100m的走廊通道模型,对不同坡度的火灾工况进行模拟,分析对比不同工况下火灾上游区和下游区烟气的烟灰浓度、温度分布规律和扩散速率,从而得出走廊坡度对烟气扩散的影响.研究结果对于人防工程内部的设计及人员疏散提供参考. 相似文献
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《消防科学与技术》2019,(11)
在康定高高原航空安全实验室(61 kPa)和广汉民用航空器火灾实验室(96 kPa),开展了常低压真实环境下FXL航空电缆护套及绝缘层的燃烧实验。采用热辐射加热箱、烟密度及成分测试仪和氧指数仪等设备,分别测量点燃时间-辐射温度、质量损失速率-氧气浓度、燃烧持续时间-氧浓度、烟密度和烟气成分等曲线,以探讨低压对燃烧特性的影响。实验结果表明:61 kPa条件下电缆护套层和绝缘层的最小点燃温度和时间皆大于96kPa;烟密度快速上升后趋于水平,护套层比绝缘层烟密度大,此外,低压比常压的发烟量小;O_2体积分数先下降至最小值后缓慢上升,CO_2随着燃烧反应先增加后减少,而CO曲线出现双峰数值;质量损失速率随着氧浓度升高而线性增大,而燃烧持续时间会快速下降。研究结果显示,常低压环境下航空电缆的燃烧特性存在差异,为预防飞机电缆火灾提供数据参考。 相似文献
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采用FDS建立典型双车道公路隧道,对海拔高度为500、4000 m的公路隧道发生火灾时的烟气蔓延特征及温度分布规律进行数值模拟分析,以得到低压、低温、低氧含量等高海拔环境对公路隧道火灾发展的影响规律.结果表明:相比较平原地区隧道,高海拔地区公路隧道火灾烟气最高温度更低,火焰高度更高,且近火源区的拱顶最高温度升温速度明显... 相似文献
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《消防科学与技术》2018,(12)
为研究不同排烟速率对建筑走廊排烟效果的影响,以某高层办公楼标准层为研究对象,采用FDS建立火灾模型,模拟分析排烟速率0、1.5、2.0 m/s下火灾烟气CO浓度、温度、能见度的变化。模拟结果表明:火灾发生后,着火房间内CO浓度在250 s时达到危险值,其余各测点处均未达到危险值;在火灾发生50 s内,除着火房间外,其余部位能见度均未达到危险值;火灾发生100 s时,着火房间温度达到60℃,此后温度继续升高,在150℃上下波动,走廊内温度均低于危险临界值;机械排烟在一定排烟速率下可有效延缓烟气扩散速度,同时可降低烟气中CO浓度、温度,但不能有效提高能见度。 相似文献
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水喷淋控制下小室火灾的数值模拟研究 总被引:1,自引:0,他引:1
研究了水喷淋控制下对小室火灾发展过程的影响,结合一安装有水喷淋的实体小室,采用数值模拟方法进行了初步分析,设计了没有喷淋、0.1MPa喷淋控制和0.2MPa喷淋控制等三种工况。结果表明,水喷淋的启动,虽然可以控制火灾的发展,降低小室内的烟气温度,但也会增加烟气的生成量,使溢出的烟气增加。同时,水喷淋的压力增加,小室内的烟气温度继续下降,CO、炭黑以及水蒸气的生成量也会随之增加。这些都对大空间的人员安全疏散以及大空间整体的消防安全带来很大的影响。 相似文献
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利用Simtec 软件模拟巴黎圣母院火灾的温度场、烟气浓度场和风流速度场。结果表明:尖塔内部出现明显的温度分区,尖塔顶部温度较低,尖塔中部以下温度较高;火源上方温度迅速达到900 ℃,然后在900~1 000 ℃上下波动,尖塔中部温度在560~720 ℃波动,十字形屋顶温度缓慢上升;火灾烟气首先充满整个尖塔,然后逐渐扩散至整个十字形屋顶;由于烟囱效应,尖塔中部的空气流速较大,形成长约15 m 的高速区域,而塔尖和塔底部空气流速较低。 相似文献
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Shin-Juh Chen David C. Hovde Kristen A. Peterson Andr W. Marshall 《Fire Safety Journal》2007,42(8):507-515
Fire detection systems located in aircraft cargo compartments are currently based only on smoke detectors. They generate about 200 false alarms per year for US registered aircraft. The number of false alarms is growing as more planes are outfitted with smoke detectors and air travel expands. Moreover, the survivability of an aircraft in a fire scenario depends on the early detection of the fire. A fire detection system is developed based on the simultaneous measurements of carbon monoxide, carbon dioxide, and smoke. The combination of the rates of rise of smoke and either carbon monoxide or carbon dioxide concentration provides a potential fire alarm algorithm to increase the reliability of aircraft smoke detectors, and to reduce the time to alarm. The fire detection system with the alarm algorithm detected fires that were not alarmed by smoke sensors, and alarmed in shorter times than smoke sensors operating alone. 相似文献
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Bosi Zhang Jiaqing Zhang Xiaomin Wang Shouxiang Lu Changhai Li Ruiyu Chen 《Fire Technology》2016,52(2):547-562
The effects of air inlet configuration on pool fire behavior in a mechanically ventilated cabin were investigated. The closed cabin used was a model of a certain machinery cabin on a naval ship. Two air inlet configurations of one vent and two vents were taken into account together with five different elevations of air inlet. In one-vent cases, mass loss rate and gas temperature were lower and oxygen concentrations were higher than those of two-vent cases. With the increase of air inlet elevation, a sudden drop in average mass loss rate and peak temperature were found in the two-vent cases at the air inlet elevation of 1.56 m. In one-vent cases, a similar drop in average mass loss rate was found at the air inlet elevation of 0.88 m, while the peak temperature was almost unaffected by inlet elevation. According to temperature profiles and the characteristic parameter of the smoke layer stability, the formation of the smoke layer was destroyed by increasing the air inlet elevation or reducing the air inlets, and furthermore a more uniform distribution could be found. For the current cabin, the one-vent case with a lower air inlet elevation was recommended for smoke control, and the inlet should be set away from the essential equipment and the entrances of the cabin. 相似文献
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摘 要:光电式火灾烟雾探测器是目前民用飞机货舱使用的主流火灾探测器,是保障飞机安全运行的关键,该探测器是基于烟雾颗粒对光的散射信号来进行报警的,但是由于空气中悬浮颗粒物(水蒸气或灰尘等)也具有散射效应,同样会触发火灾探测器发生报警,这种原理上的缺陷造成的误报情况时有发生。通过对飞机货舱典型燃烧物瓦楞纸片、榉木和棉绳的蓝光散射功率(表征为表面积浓度)、红外光散射功率(表征为体积浓度)和颗粒物索特平均粒径火灾特征参数进行分析,为复合探测器的研发优化火灾特征参数。结果表明:在常压条件下,蓝光和红外光对颗粒物浓度的变化有很好的响应,索特平均粒径可以区分火灾烟雾颗粒和非火灾烟雾颗粒,可以有效降低误报率。 相似文献