共查询到18条相似文献,搜索用时 15 毫秒
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针对现有的细水雾系统设计规范中对雾滴大小要求不明确的问题,研究了细水雾抑制煤油池火的最佳雾滴大小。通过对细水雾熄灭油池火的主导机理研究,得到细水雾熄灭煤油池火的必要条件是水雾能够在雾滴损失的特征时间内到达燃料表面,进而通过理论计算得到细水雾熄灭煤油池火的临界雾滴大小。通过10组不同粒径大小的细水雾喷头进行实验验证。结果表明,在最佳雾滴大小范围内的细水雾比最佳雾滴大小范围外的细水雾熄灭煤油池火的时间短。 相似文献
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对细水雾近距离扑灭油盘火焰进行了实验和理论分析。实验结果表明:利用水雾近距离扑灭油盘火时,水雾射流对火焰的吹熄作用是火焰熄灭的主导机理;气流对火焰的拉伸冷却和细水雾对火焰的蒸发冷却能使火焰的蔓延速度降低,对吹熄起促进作用;而化学反应动力学特征对火焰抵抗吹熄的能力也有重要影响。 相似文献
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不同工况下细水雾灭火效能影响的数值模拟 总被引:1,自引:0,他引:1
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. 相似文献
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从变压器油的燃烧特性出发,通过实验室小尺度模拟实验,对细水雾和CO2抑制并扑灭变压器油油池火灾进行了研究,评估细水雾扑灭此类火灾的优势性、依赖因素及变化规律。研究表明,用细水雾扑灭变压器油油池火是可行的,在施加细水雾后火焰温度明显下降,火焰迅速减小,直至熄灭,且相比较CO2,细水雾灭油池火不但防复燃效果好,也更加安全无毒。 相似文献
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利用全开放式小型高压细水雾灭火装置组织开展了两种不同油量的油盘在外加风量作用下的燃烧灭火试验,通过观察高压细水雾双喷头在外加风量作用下的对射灭火效果,实时采集高压细水雾灭火过程中的视频图像与温度变化数据,并对比分析自由燃烧状态下的正常油盘火,对高压细水雾扑灭变压器油池火的实际效果做出了有效的量化评估。 相似文献
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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。 相似文献
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建立固定式细水雾灭火试验平台,探究添加表面活性剂添加剂后,细水雾扑灭油池火时的温度变化特性和火焰形态。对汽油、柴油池火的火焰温度及灭火时间的对比表明,在细水雾中添加表面活性剂添加剂能大幅提升细水雾灭火性能;含添加剂的细水雾抑制池火过程分为火焰初期增长、初步抑制、火焰再次增长和再次抑制4个阶段;含添加剂细水雾系统的灭火机理在于可以捕捉和湮灭链式反应中的自由基,降低表面张力。 相似文献
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杜文锋 《消防技术与产品信息》2013,(8):74-76
总结了细水雾灭火机理的国内最新研究进展,提出了细水雾局部应用灭火时的吹熄灭火机理,阐释了细水雾全室淹没灭火时,灭火时间随燃烧热释放速率和开口面积变化的规律,分析了在不同热释放速率下细水雾对室内燃烧灭火的贡献。 相似文献
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LIU Zhi-gang DON CARPENTER ANDREW K. KIM 《消防科学与技术》2006,25(2):223-232
大型商用燃油炊具面积巨大,并涉及到大量热油,灭这种大型商用燃油炊具火灾非常困难。利用水雾系统对大型商用燃油炊具保护进行了研究,从理论和试验对水雾系统的灭火机理以度扑灭大型油池火灾需要达到的相关标准进行了研究。根据灭火机理和相关标准,设计了两套水雾灭火系统,进行了一系列的实体火灾试验。研究表明,两套水雾灭火系统成功地扑灭了大型油池火灾,有效预防了复燃。其灭火性能取决于水雾系统类型、喷射压力以及炊具罩的位置。 相似文献
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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. 相似文献
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Zhigang Liu Andrew K. Kim Don Carpenter J. M. Kanabus-Kaminska Ping-Li Yen 《Fire Technology》2004,40(4):309-333
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. 相似文献
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为研究大型换流变火灾外围池火燃烧特性及灭火要求,建立了换流变火灾试验模型,研制了换流变实体火灾灭火试验平台,通过开展池火燃烧及泡沫-细水雾灭火试验研究,分析了火灾时换流变外围温度场特性。试验表明:模型中换流变油池火燃烧行为与实际换流变火灾类似,池火贴壁燃烧且卷吸效应明显,阀侧火的羽流温度高于其他区域,换流变壁面快速升温致使钢材屈服强度降低,局部结构出现变形,换流变内部变压器油、防火墙壁面升温缓慢。泡沫细水雾联用系统灭火可快速扑灭明火,降温、隔氧效果明显。 相似文献
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Experimental study of the effect of water spray on the spread of smoldering in Indonesian peat fires
Peatland fires remain a major contributor of environmental problems in Indonesia. Several studies on peat fire suppression have been conducted with multiple methods, such as quarrying, water spray, artificial rain, and foam spray. This research is focused on laboratory scaled experiments of Indonesian peat smoldering fire behaviour and suppression by a water mist system. The peat used in this work was obtained from two different locations, namely Papua and South Sumatra, Indonesia. During the suppression tests, the intensity of the water mist spray was varied by changing the distance between the nozzle and the peat surface. Meanwhile, the time periods of spray were 15 min (short period of suppression) and approximately 2 h for full suppression until the peat fire was extinguished. The peat temperature and the total mass lost during the smoldering reaction were recorded to get the burning rate ratio for each sample. The spread rate of the smoldering process was identified by the changes in the local temperatures of the peat bed. The results show that the spread rate of the smoldering combustion front was affected by particle size and permeability of peat material. The short duration of water suppression failed to extinguish the peat fires. A re-ignition phenomenon was identified due to the persistence of stored heat in the core of the peat. In addition, the total water required to fully suppress both peat fires is about 6 L/kg peat. 相似文献