细水雾在铁路隧道救援站的应用研究

为研究细水雾在铁路救援站内的灭火特性,在30 m×6 m×6 m的铁路救援站模型布置了细水雾灭火系统,开展火灾试验。在轮胎火工况下,分别在不同细水雾喷头高度的情况下,对管网末端压力、隧道内细水雾颗粒粒径分布以及细水雾的灭火效果进行试验。结果表明,管网高度对管网末端压力和细水雾颗粒粒径影响较小;压力越大,流量越大,细水雾浓度越大;细水雾能有效抑制轮胎火。     

受限空间内脉冲细水雾灭木垛火试验

为研究循环动作时间对细水雾扑灭木垛火效果的影响,搭建了脉冲细水雾灭火试验平台,改变细水雾循环动作时间,在1.5m×1.5m×1.5 m的受限空间内进行了灭火试验,分析了脉冲细水雾作用过程中温度场及氧含量的变化。研究表明,脉冲细水雾对木垛火有很好的抑制作用,能够在较短的时间内熄灭木垛表面明火,但无法彻底扑灭木垛内部火;针对试验中的木垛尺寸及形式,喷10s、停10s是一个最佳的脉冲时间参数,在该工况下灭火效率最高、灭火效果最好。     

超细水雾全尺寸灭火试验研究

采用超细水雾全淹没灭火装置在3m×3m×3m的全尺寸密闭空间内进行庚烷火灭火试验,从而验证超细水雾在较大密闭空间内灭庚烷火的适用性。试验采用200mL/min和500mL/min的超细水雾灭火装置同时施加超细水雾,试验火源分别使用40kW和120kW的庚烷火,产雾所用的水分别采用纯水和含碳酸氢钠的水溶液,通过四种不同工况验证超细水雾的灭火效果。试验结果表明,超细水雾可扑灭较大密闭空间内的庚烷火,NaHCO3能够显著增强超细水雾的灭火效果。     

细水雾灭火系统在核电厂综合管廊中的应用

搭建了某核电厂综合管廊典型区域全尺寸试验模型,并在试验模型内设置了分区控制的高压细水雾灭火系统进行全尺寸灭火试验。设置长边区域、交叉区域的不同火灾工况,分析细水雾灭火系统在管廊不同区域灭火时的温度、热辐射以及烟气浓度的变化情况,研究高压细水雾灭火系统在该场所的灭火有效性。研究结果表明,高压细水雾灭火系统对于综合管廊不同区域内电缆火的抑制和扑灭效果良好。     

含添加剂细水雾灭油池火的实验研究

采用析出式气泡雾化系统,在受限空间内使用质量分数为1%、不同种类的添加剂和纯细水雾进行灭油池火的对比实验,通过喷嘴雾化特性、灭火时间、火焰温度分布、CO含量变化对不同压力下熄灭油池火的机理和有效性进行分析。实验结果表明:灭柴油火时,含1%KCl添加剂细水雾的灭火效果最佳,化学灭火作用占主导;灭汽油火时,含1%SDBS添加剂细水雾的灭火效果最佳;不同种类的添加剂呈现出不同的灭火效果,但都优于纯细水雾。     

不同工况下细水雾灭火效能影响的数值模拟

采用FDS对单室火灾中细水雾与火焰相互作用过程进行数值模拟分析,探讨细水雾与火焰相互作用过程中不同区域的细水雾灭火机理,分析粒径分布、速度和雾化角度对细水雾灭火产生的影响.模拟结果表明:在细水雾与火焰相互作用过程中粒径分布对灭火效能影响显著;细水雾在粒径小于100 μm时不能实现有效灭火;当粒径为200～400 μm时细水雾能有效抑制火焰发展并熄灭火源;在细水雾灭火机理中,相对于气相冷却和隔氧窒息,细水雾的表面冷却作用起到主导作用;细水雾喷射速度对灭火效果影响较大,细水雾动量不小于火羽流动量是火灾发展得到有效控制的重要前提;细水雾有效雾通量随着雾化角度增大而逐渐减小,雾化角度增大不利于细水雾灭火效能提高.     

纵向风速对隧道细水雾灭火效果影响探讨

摘 要：为了探究细水雾和纵向通风共同作用下隧道内烟气运动情况,确定配置有细水雾灭火系统的隧道最佳通风策略。采用FDS建立了隧道细水雾数值模拟模型,分别计算了不同纵向风速情况下隧道内温度、有害气体浓度及辐射热通量的变化情况。结果表明：30 MW火灾规模下,烟气层在火源上风向15 m的喷雾区开始出现逐渐层降,烟气层下降至2 m以下;至300 s灭火结束时,上风向150 m内,烟气层全部下降至2 m以下。故火灾发生5 min后,人员疏散距离应大于150 m。对比相同通风风速下（1 m/s）细水雾施加前后辐射热通量变化情况得出,开启细水雾灭火系统25 s后,火源下游5 m处热辐射强度由6 kW/m2降至0。建议开启细水雾灭火系统时尽量保持隧道内1 m/s的通风风速。     

细水雾灭火系统在小型汽车库火灾中的灭火效能试验研究

摘 要：针对小型汽车库的火灾防控,建立了5.95 m×7.6 m×3.6 m全尺寸汽车库火灾试验平台,研究了高压细水雾灭火系统单个喷头在不同系统工作压力（6,8,10 MPa）下的洒水分布性能,分析确定了小型汽车库细水雾灭火系统设计参数及喷头布置位置;并采用细水雾灭火系统对汽车库内汽车后座火灾开展了灭火试验研究。结果表明：采用高压细水雾灭火系统能有效抑制小型汽车库内汽车火灾发展,并可很好地保护汽车库的围护结构及相邻汽车。本文研究确定小型汽车库的高压细水雾灭火系统采用闭式系统,系统工作压力为10 MPa,设计喷雾强度不小于2.0 L/（min·m2）,流量系数取K=3.0等设计参数以及喷头的布置位置,可使灭火系统达到较好的灭火、控火效果。     

低压细水雾灭火系统在隧道火灾中的灭火性能研究

本文在云南省安楚公路芹菜塘1号隧道内开展了全尺寸现场模拟火灾实验,验证低压细水雾灭火系统在公路隧道火灾中的控火能力。实验证实,针对隧道中1m×2 m油池火、2 m×2 m油池火、4 m×4 m油池火,在隧道的通风良好的情况下,低压细水雾灭火系统开启后可以有效降低隧道内的环境温度以及火源周围CO浓度。     

侧向喷射条件下细水雾扑灭水平表面流淌火研究

为探讨侧向喷射条件下细水雾扑灭流淌火的技术可行性,针对水平表面流淌火,在考虑火焰辐射、燃料与垫层之间的对流换热基础上,建立细水雾在开敞空间扑灭流淌火理论模型,实验研究细水雾喷头排数、倾斜角度对火焰形状、火焰温度、灭火机理和灭火时间的影响。结果表明：细水雾冲击燃料加快其流淌时可以增强灭火能力;采用单排喷头水平喷射时可有效抑制一侧火焰且对火焰拉伸作用最强;采用双排喷头水平喷射时,可有效抑制两侧火焰且灭火速度最快;当喷头向上倾斜15°时,细水雾冷却燃料能力减弱并使灭火时间变长。     

Extinguishment of Cooking Oil Fires by Water Mist Fire Suppression Systems

A series of full-scale experiments were conducted in a mock-up commercial cooking area to study extinguishing mechanisms and effectiveness of water mist against cooking oil fires. The impact of water mist characteristics, such as spray angle, droplet size, flow rate, discharge pressure and type of nozzle, on the effectiveness of water mist against cooking oil fires was investigated. A series of oil splash experiments were also conducted to determine if the oil was splashed by water mist. In addition, the change in oil composition during heating and fire suppression was determined using Fourier Transform Infrared (FTIR) technique.The study showed that cooking oil fires were very difficult to extinguish, because they burned at high temperature and re-ignited easily due to changes in oil composition during heating and fire suppression. The water mist systems developed in the present work effectively extinguished cooking oil fires and prevented them from re-ignition. The spray angle, discharge pressure, and water flow rate were important factors to determine the effectiveness of water mist in extinguishing cooking oil fires.     

单、双喷头细水雾对正庚烷池火灾的抑制作用

为了研究单、双喷头细水雾抑灭正庚烷池火灾的效能和机理,在半体积飞机模拟货舱中开展了单、双喷头细水雾雾滴粒径测试和抑灭20 cm 正庚烷池火灾的实验研究。结果表明,双喷头细水雾协同工作会导致雾滴之间相互碰撞发生二次破碎,有助于雾化效果的提升。通过对燃料表面温度、火焰区平均温度和舱内氧气浓度的测量和计算,对比分析了单、双喷头细水雾抑灭火的主导机理。结果表明,单喷头细水雾灭火的平均时间为283.14 s,耗水量约为3.54 L,燃料表面冷却是其抑灭火的主导机理。双喷头细水雾灭火的平均时间为212.22 s,耗水量约为5.31L,火焰冷却是其抑灭火的主导机理。     

浅谈高层住宅厨房排烟道系统

本文介绍了高层住宅烟道的发展历程,并结合《重庆市住宅厨房、卫生间排烟(风)道性能检测标准》对烟道系统做了简单的分析。     

住宅厨房利用热压集中排烟模式初探

对多、高层住宅厨房的燃烧废气和烹饪排烟在无机械装置的集中式烟道中的各种自然排烟过程进行热工学和流体力学分析计算，并对该集中烟道的尺寸进行优化设计计算，为试验研究提供理论依据和基础数据。计算结果表明，这种利用热压进行无能耗排烟的方式可应用于30层以下多、高层住宅厨房的排烟，所需烟道尺寸与目前使用机械排烟方式的集中式烟道相当，具有节能、环保的应用前景。     

熄灭森林阴燃火的细水雾喷头设计与仿真

森林大火后的残余地表余火及地下阴燃火是引起二次森林火灾的主要原因,为防止发生二次森林火灾,清理森林余火和阴燃火是必要的.细水雾作为哈龙灭火剂的最佳替代品,被广泛应用在消防领域.本文设计一种适合熄灭森林余火和阴燃火的撞击分流高压细水雾喷头,采用Fluent进行喷头流域的仿真,分析喷孔孔径、喷孔长度和喷孔喷雾锥角对喷出细水...     

Assessment of the Fire Dynamics Simulator for Modeling Fire Suppression in Engine Rooms of Ships with Low-Pressure Water Mist

Water mist-based fire-extinguishing systems are gaining acceptance for the protection of ship machinery spaces. The use of simulation tools presents a great potential for taking a performance-based design (PBD) approach to these fire scenarios. The Fire Dynamics Simulator (FDS) is the most frequently used and validated fire modeling software; however, studies of low-pressure water mist fire suppression modeling in ship engine rooms are rare. This paper contributes to the current literature by using the FDS to model a series of fire suppression scenarios defined by the International Maritime Organization (IMO) Circulars, including spray and pool fires with heptane and diesel oil, as well as exposed and obstructed fires. The simulation results are compared to data from full-scale tests conducted at recognized fire testing laboratories. Furthermore, an analysis of both the experimental and model uncertainties is carried out to assess the simulations performance. In general, a good agreement in compartment temperature evolution and fire extinguishing time is found for the modeled fire scenarios. The results support the application of FDS in a PBD approach for the design of water mist fire extinguishing systems for machinery spaces in ships. In this way, designers and engineers could model different machinery volumes and nozzles spacings that differ from those prescribed for a one story square engine room of the IMO, and, thus, predict the evolution of temperatures and extinguishing times for get the authorities approval.     

细水雾系统参数对有障碍物液体火灾灭火效果的影响

利用FDS 数值模拟软件，采取控制变量法设置4 组数值模拟，分别研究细水雾系统水滴粒径、雾化角度、喷水强度、喷头高度对火源周围存在无法燃烧或尚未开始燃烧的障碍物情况下灭火效果的影响。研究发现，当火源设置为乙醇池火时，存在障碍物条件下，细水雾系统水滴粒径设置在250~400 μm，雾化角度设为120°，喷水强度设为2.0~2.5 L/（min·m2），喷头高度距障碍物1 m 时灭火效果较为理想。     

A study of portable water mist fire extinguishers used for extinguishment of multiple fire types

This paper describes both theoretical and experimental studies on the application of a portable water mist extinguisher in suppressing multiple fire types. Two prototype portable water mist fire extinguishers were developed and their feasibility in extinguishing flammable liquid, cooking oil and wood crib fires, and for use in fires associated with an energized target was investigated. The interaction between water mist and the fire plume was studied by analyzing the instantaneous process of fire extinction, and fire and fuel temperature profiles. Both theoretical analysis and experimental results showed that the extinguishing mechanisms and process as well as water mist characteristics required (such as water flux density, droplet size and spray coverage) change with the types of fires encountered. The portable water mist extinguisher with appropriate mist characteristics was able to extinguish multiple fire types.     

Large-Scale Water Spray and Water Mist Fire Suppression System Tests for the Protection of Ro–Ro Cargo Decks on Ships

This paper summarises a series of large-scale fire suppression tests conducted to simulate a fire in the trailer of a heavy goods freight truck on a roll-on roll-off (ro–ro) cargo deck. The tests were conducted with a traditional deluge water spray system as well as a deluge high-pressure water mist system. Parameters such as the water discharge density, the system operating pressure, the nozzle K-factor and whether the fire was fully exposed to the water spray or shielded were varied. The total and convective heat release rate of the fire was measured in order to determine the fire suppression and fire control capabilities of the tested systems. Test results indicate that a water discharge density of at least 10 mm/min is necessary to provide fire suppression of a fire in a heavy goods freight truck, whilst 5 mm/min would provide fire control. Furthermore, the test results indicate that a high-pressure water mist system would require higher flow rates as compared to a traditional water spray system in order to provide fire control.