机械排烟和细水雾对地下商场火灾控制作用的研究

发布时间：2018-01-13 22:38

本文关键词：机械排烟和细水雾对地下商场火灾控制作用的研究　出处：《沈阳建筑大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着城市快速发展,人口数量不断增多,地下建筑应运而生并成为城市商业发展的重要组成部分。地下建筑与地上建筑相比,因空间封闭、人员密集等特点,不利于火灾扑救和人员安全疏散,大量高温有害烟气造成人员伤亡及财产损失。因此,在地下建筑防火尤其是地下商业建筑防火中,应根据火灾烟气流动规律设置防排烟系统及细水雾灭火系统,采取科学有效的控制方案最大程度保障人身安全。论文首先建立了小尺寸火灾模型实验台,测试分析不同工况下机械排烟和细水雾对火场温度变化和烟气层演化规律的影响,结果表明：单独开启机械排烟系统,排烟口断面平均风速为1m/s时烟气控制效果较好；单独开启细水雾系统时,细水雾喷头流量6.25L/min、 9 L/min及12.5 L/min的灭火效果存在细微差距,但由于细水雾的施加,却出现了细水雾施加初期时柴油火源强化燃烧现象,且流量越大,现象越显著。从经济性和效果考虑,选取6.25L/min的细水雾喷头流量性能最好；机械排烟和细水雾共同开启时,虽然对火源表面的冷却作用稍弱,但是对火焰以及烟气层的冷却效果显著,火灾现场能见度大为改善,便于人员逃生。进一步地,本文运用火灾动力学模拟软件FDS建立火灾模型,对大空间地下商场火灾进行模拟分析。通过分析可燃物附近测点的模拟数据,得出火源中心面温度、一氧化碳浓度、烟气层高度、能见度等参数随时间的增长特性,发现在5MW火灾功率负载下,排烟量为60m3/(h.m2)时,可达到较好的烟气控制效果。利用相同模型分析补风量分别为排烟量的50%、60%及80%三种情况对火灾烟气的控制效果,研究表明：在机械排烟系统开启时,补风量与排烟效果并不成正比关系。补风量越大,燃烧越剧烈,火场温度越高,而CO浓度较低,烟气层较高,对于人员逃生和健康相对有利；根据单独设有细水雾时各项参数的变化情况,确定出90s开启细水雾系统,喷头工作压力为10MPa时,流量为15L/min可达到较好灭火效果；在相同火源功率下,对机械排烟和细水雾共同作用时的结果分析可知：将排烟量的50%作为补风量,细水雾流量设置为15L/min能达到最优的控制效果。
[Abstract]:With the rapid development of city population, the growing number of underground buildings came into being and become an important part of city commercial development. Compared to underground buildings and buildings on the ground, because the space is closed, personnel intensive characteristics, is not conducive to the fire fighting and evacuation of large volume, high temperature and harmful gas caused casualties and property losses. Therefore, in the underground building fire especially underground commercial building fire, according to the flow law of fire smoke set fire extinguishing system of smoke control system and control scheme of water mist, adopt scientific and effective guarantee for maximum safety. The paper established a small fire model experiment, test and analysis of mechanical exhaust and water mist under different conditions of influence fire, temperature and smoke layer evolution. The results showed that the single open mechanical exhaust system, the average wind speed is 1m/s when the smoke exhaust port section Gas control effect is better; alone open water mist system, water mist nozzle flow in 6.25L/min, there is a slight gap between 9 L/min and 12.5 L/min fire extinguishing effect, but due to application of the water mist, there was water mist applied early fire diesel enhanced combustion phenomenon, and the greater the flow, the phenomenon is more significant from the economic consideration. And the effect of water mist nozzle flow properties of selected 6.25L/min best; mechanical exhaust and water mist to open, while the cooling effect of fire on the surface of the weaker, but the flame and the cooling effect of the smoke layer significantly, fire scene visibility is greatly improved, easy to escape. Further, this paper established the model of fire fire dynamics the FDS simulation software, simulation analysis of the large space underground mall fire. Through the analysis of the simulated data of combustible near the measuring point, the fire center surface temperature, oxidation Carbon concentration, smoke layer height, growth characteristics of visibility parameters with time, found in the 5MW fire power under load, exhaust volume is 60m3/ (h.m2), can achieve good smoke control effect. The analysis of secondary air volume respectively smoke volume 50% using the same model, show that the control effect of 60%, 80% and three the fire smoke: in the open mechanical exhaust system, supply air and exhaust effect is not proportional to the volume of air supply. The more fierce, burning, the temperature is high, but the lower concentration of CO, the smoke layer is high, for the evacuation and health is relatively favourable; according to the changes in the parameters of a single fine when the mist, determined 90s open water mist system, sprinkler working pressure is 10MPa, flow rate of 15L/min can reach better extinguishing effect; in the same fire power, the mechanical exhaust and water mist jointly by the results of analysis The best control effect can be achieved by setting 50% of the amount of exhaust smoke as the amount of supplementation and setting the flow of fine water mist to 15L/min.

【学位授予单位】：沈阳建筑大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU967;TU998.1

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