喷淋对建筑火灾流场影响的数值模拟研究

发布时间：2018-05-13 11:10

本文选题：数值模拟 + 建筑火灾　；参考：《安徽理工大学》2013年硕士论文

【摘要】：随着城市化进程的不断加速,使得各类建筑迅猛增多,火灾危害性增加。而自动水喷淋系统由于其敏感度高、灭火可靠、经济实用、易于维护等优点在建筑防灭火领域被普遍使用。了解水喷淋对火灾流场的影响规律,能够为规范布置喷头提供理论依据,以发挥喷淋系统的最佳控火效果。本文借助FDS数值模拟软件,在流体力学理论的基础之上,对某阅览室火灾时不同工况参数的改变对火灾流场的影响进行理论分析和模拟研究,以得出不同工况参数对火灾流场的影响规律。首先,在烟气蔓延理论与喷淋喷洒理论的基础上,指出火灾烟气对人员逃生的危害性,并给出喷淋水滴的拖拽力会造成烟气层紊乱,发生“烟气拥塞”,进而形成“拥塞射流”、“尾流”等阻碍火灾现场人员的安全疏散。然后,结合某阅览室的现场概况合理的划分网格、选取模拟时间,并选择适当的火灾荷载、火灾发展模型和喷淋参数,设置了8个不同喷淋场景,并利用PyroSim、FDS模拟工具,建立了阅览室喷淋作用下火灾流场模拟模型。最后,将8种不同火灾工况进行数值模拟,分析模拟结果。总结得出：水喷淋的启动不仅对阅览室火灾发展有明显的抑制作用,还可以将火灾热烟气控制在顶棚附近,保障了非火源区域的人员疏散安全,但同时会阻碍烟气排放,加快烟气层的增厚速度,加快能见度的下降,并致使产生大量的CO,但是整个过程中的CO浓度峰值有所降低；相同喷淋间距,增加单个喷头流量,可以小幅度的降低烟气温度,同时会导致CO浓度的略微升高和室内烟气流的紊乱,使得火灾现场更加混乱；相同单个喷头流量,缩短喷淋间距,能降低温度峰值,减慢烟气温度的上升速度,同时也会使得室内的烟气紊流加剧,导致CO浓度升高。研究过程和结论可为其他类似建筑物场景消防安全设计提供参考性依据,对引导人员安全疏散救援有一定的现实意义。
[Abstract]:With the acceleration of urbanization, all kinds of buildings are increasing rapidly and the fire hazard is increasing. The automatic water spray system is widely used in the field of building fire prevention and extinguishing because of its high sensitivity, reliable fire extinguishing, economical and practical, easy to maintain and so on. Understanding the influence law of water spray on fire flow field can provide theoretical basis for the standard layout of sprinkler, so as to give play to the best fire control effect of sprinkler system. Based on the theory of hydrodynamics, this paper makes theoretical analysis and simulation study on the influence of different working conditions parameters on the fire flow field in a reading room based on the FDS numerical simulation software. The effects of different operating conditions on the fire flow field are obtained. First of all, on the basis of the theory of smoke spread and spray spraying, this paper points out the harm of fire smoke to the escape of personnel, and points out that the drag force of spray water droplets will cause the smoke layer disorder and "smoke congestion". The formation of "congestion jet", "wake" and other obstacles to the safe evacuation of fire site personnel. Then, combining with the reasonable grid of a reading room, selecting the simulation time, choosing the appropriate fire load, fire development model and sprinkler parameters, eight different sprinkler scenes are set up, and the simulation tools of PyroSim-FDS are used. The simulation model of fire flow field under the action of sprinkling in reading room is established. Finally, eight different fire conditions are simulated and the simulation results are analyzed. It is concluded that the start-up of water spray can not only restrain the development of the reading room fire, but also control the fire hot smoke near the roof, which ensures the safety of evacuation in the non-fire area, but also hinders the smoke emission. Accelerate the thickening speed of smoke layer, accelerate the decrease of visibility, and cause a large amount of CO-producing, but the peak value of CO concentration in the whole process is reduced; the same spray spacing and increasing the flow rate of a single sprinkler can reduce the flue gas temperature by a small margin. At the same time, it will lead to a slight increase in CO concentration and disturbance of indoor smoke flow, which will make the fire site more chaotic. The same single nozzle flow rate, shortening spray spacing, can reduce the peak temperature and slow down the rising speed of flue gas temperature. At the same time, the indoor flue gas turbulence will be intensified, resulting in the increase of CO concentration. The research process and conclusion can provide reference basis for other similar building scene fire safety design, and have certain practical significance to guide personnel safety evacuation and rescue.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU892;TU998.1

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