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通过模拟实验研究了细水雾与火灾烟气的相互作用,揭示了细水雾作用下烟气温度及组分浓度的变化规律。同时利用FDS程序计算了细水雾作用下烟气温度和组分浓度随时间的变化规律,利用实验数据对计算结果进行了准确性验证。结果表明只要计算网格匹配合理,FDS可以较为准确地预测细水雾作用下烟气温度和组分浓度的变化规律。在实际的细水雾灭火系统工程应用中,可以利用FDS场模拟方法预测灭火过程中火场温度及组分浓度等特性参数的变化规律,这对灭火系统的优化设计具有一定指导意义。 相似文献
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采用热重分析法对餐饮业油烟道油垢的燃烧过程进行实验研究和理论分析,分别在5,15,25℃/min升温速率空气气氛中,研究油烟道油垢的燃烧特性以及升温速率对着火温度、可燃性指数的影响.油垢从常温升至800℃共经历了五个阶段:第一阶段为水分析出过程,第二阶段到第五阶段为燃烧失重过程.采用Doyle和Coats-Redfern方法建立了"四阶段一级反应动力学模型".结果表明,油垢燃烧失重的后四个过程均可用简单反应动力学模型进行简化,为1反应级数. 相似文献
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《制冷与空调(四川)》2019,(6)
为讨论防护工程火灾时非火源房间内烟气特性,根据相似原理搭建了模型与实体比例为1:4的单室-走廊-单室模型实验台,进行了2个工况的模型实验,对比研究分析了烟气扩散室内和门口走廊中烟气温度、CO浓度、CO_2浓度及O_2浓度等烟气特性。结果表明,火灾发展阶段,扩散室内的烟气温度比门外走廊处低,烟气中CO、CO_2和O_2对人体的危害性比走廊处小,烟气温度和浓度变化滞后于走廊;火灾充分发展阶段烟气扩散室中烟气温度和浓度与走廊中几乎相同。火灾时,远火源端单室中烟气危害更大。 相似文献
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为了分析公交车的火灾特点,本文采用美国国家标准和美国技术研究院(NIST)开发的FDS软件,建立了公交车火灾模型,并进行全尺寸模拟,模拟发现:在火灾发展过程中温度在60s内即可达到危险值并在200s左右达到峰值;同时烟气扩散至不利于乘客疏散的高度;在人员呼吸高度处,氧气浓度在45s内即可降到6%以下。 相似文献
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《制冷与空调(四川)》2019,(3)
针对轨行区列车火灾的烟气控制问题,提出了一种利用隧道风机进行双向排烟的方式。根据典型屏蔽门制式地铁车站结构建立无轨顶风道的车站三维模型,采用数值模拟方法对该排烟方式下的烟气扩散规律进行研究,分析了不同排烟量下站台人员高度处烟气温度、CO浓度以及能见度的分布情况,给出了不同车站隧道横截面积下满足人员安全疏散条件时的隧道口最小排烟量。 相似文献
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运用FDS(Fire Dynamic Simulation)火灾模拟软件对三种不同环境温度和火灾强度(共九种工况)条件下的某竖井型自然通风隧道火灾进行了数值模拟,并对模拟的结果进行了对比和分析,得到了隧道环境温度和火灾强度对隧道火灾时烟气浓度分布的影响规律。 相似文献
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《制冷与空调(四川)》2020,(1)
为讨论防火卷帘对防护工程火灾时走廊内烟气扩散的影响,根据相似原理搭建了模型与实体比例为1:4的单室-走廊模型实验台,进行了2个工况的模型实验,分析了走廊内烟气温度分布,研究了不同工况条件下走廊内CO浓度、CO_2浓度及O_2浓度等烟气特性。结果表明,防火卷帘关闭后走廊中最高温度有所降低,走廊中温度竖向分布更加趋于一致,烟气的热分层稳定性降低;卷帘门关闭后导致烟气浓度发生变化的时间提前,且烟气浓度的极值向对人员安全不利的方向显著发展;建议火灾初期和人员未完全逃出防火分区时防火卷帘处于开启状态,当人员安全疏散出防火分区后再关闭。 相似文献
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《制冷与空调(四川)》2019,(5)
为讨论火源位置对防护工程火灾时走廊内烟气扩散的影响,根据相似原理搭建了模型与实体比例为1:4的单室-走廊模型实验台,进行了2个工况的模型实验,分析了走廊内烟气温度分布,研究了火灾分别位于走廊和单室时走廊内烟气温度、CO浓度、CO_2浓度及O_2浓度等烟气特性。结果表明,火源位于走廊时,走廊内烟气最高温度、平均温度及烟气温度变化速率均大于火源位于单室时,火源位于走廊时走廊内CO浓度、CO_2浓度及O_2浓度与火源位于单室相比对人员也更不利,应避免在工程的走廊内放置易燃、可燃物品,尤其是高热值物品。 相似文献
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依托工程实际,采用数值模拟方法研究隧道火源位于不同车道时,隧道临界风速、温度、烟雾分布扩散规律。结果表明:纵向通风速度不大于临界通风速度时,火源下游段隧道棚顶温度呈e函数下降,当通风速度大于临界通风速度时,该规律不再适用。火源位于侧壁面时,由于隧道侧壁面的限制作用,其近火源区烟气运移呈“之”字形向隧道出口处蔓延,隧道棚顶不同纵向温度线呈滚动式交替变化。 相似文献
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燃煤机组湿法脱硫后,产生的湿烟气由烟囱排入温度较低的环境中会遇冷凝结,即冒“白烟”现象。建立了燃煤机组各“消白”技术的排烟温度的理论计算模型,并以西安、石家庄、上海地区为例计算研究不同地区“消白”技术的特点。结果表明,环境温度较高时,烟气直接加热法可有效消除白烟;环境温度低时,烟气降温再热法可以更有效地消除白烟。春夏季可以采用直接加热法消除白烟,排放烟温根据环境因素应控制在60~75℃;在秋冬季,当环境温度在9℃、相对湿度为60%以下时,建议采用降温再热法消除白烟,秋季可先降到45℃再加热到75℃排放,冬季可先降到45℃再加热至85℃排放。 相似文献
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设定了两种火灾规模,以1:10模型比例对南京市某自然通风城市隧道进行了火灾时隧道内温度场的分布规律的模拟试验。试验结果表明,在大火灾强度下,温度场纵向影响范围相应增加;在隧道两口部存在温差的情况下,隧道内烟气主要向口部温度较高一侧的通风口扩散;在烟气经过通风竖井之后,烟气的温度有显著降低,证明自然通风竖井能够排出大量的烟气,并带走大部分热量,烟气会因热动力不足而发生沉降现象。 相似文献
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Modeling fire-induced smoke spread and carbon monoxide transportation in a long channel: Fire Dynamics Simulator comparisons with measured data 总被引:1,自引:0,他引:1
Smoke and toxic gases, such as carbon monoxide, are the most fatal factors in fires. This paper models fire-induced smoke spread and carbon monoxide transportation in an 88m long channel by Fire Dynamics Simulator (FDS) with large eddy simulation (LES). FDS is now a well-founded fire dynamics computational fluid dynamic (CFD) program, which was developed by National Institute of Standards and Technology (NIST). Two full scale experiments with fire sizes of 0.75 and 1.6MW were conducted in this channel to validate the program. The spread of the fire-induced smoke flow together with the smoke temperature distribution along the channel, and the carbon monoxide concentration at an assigned position were measured. The FDS simulation results were compared with experimental data with fairly good agreement demonstrated. The validation work is then extended to numerically study the carbon monoxide concentration distribution, both vertically and longitudinally, in this long channel. Results showed that carbon monoxide concentration increase linearly with the height above the floor and decreases exponentially with the distance away from the fire source. 相似文献
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Polymer's melt flow behavior has triggered great interest due to the mutual-enhancing loop effect between vertical polymer fire and the induced flowing pool fire. The aim of the study was to quantitatively investigate the effect of ignition conditions on the polymer's melt flow flammability. Polypropylene (PP) sheets with a thickness of 4mm were selected as the test samples. An experimental rig was designed to study the interaction between the vertical PP sheet fire and the corresponding pool fire. Ignition was achieved at three locations, i.e. the lower right corner, the lower middle edge, and the whole lower edge of the PP sheets. All tests were conducted in an ISO9705 fire test room. Heat release rate, smoke temperature and other common parameters in fire hazard analysis were measured with the help of the fire room facilities. Results indicated that ignition conditions evidently impact on heat release rate development, peak heat release rate, smoke temperature, smoke generation and smoke toxicity. Furthermore, these experimental results preliminarily demonstrated the feasibility of the designed setup in studying interaction between vertical polymer sheet fire and the induced pool fire, although further modification may be needed. 相似文献
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Confinement of fire-induced smoke and carbon monoxide transportation by air curtain in channels 总被引:1,自引:0,他引:1
Experimental and numerical studies were performed in this paper to study the possibility of utilizing air curtain for confinement of fire-induced smoke and carbon monoxide transportation along channels. Bench scale experiments were preliminarily performed in a 3.6 m long model channel. Complementary computational fluid dynamics (CFD) simulation was carried out by Fire Dynamics Simulator (FDS) for an 88 m long full scale channel, in order to see the longitudinal carbon monoxide concentration distribution along the real channel with air curtain discharged. Results showed that both the smoke and CO gases released by the fire were well confined to almost remain in the near fire region of the channel at one side of the air curtain. The gas temperature and CO concentration in the protection zone at the other side reduced significantly by an exponential trend with the increase of discharge velocity of the air curtain. These indicated that the air curtain can be an effective measure for confining the transportation of smoke and carbon monoxide species in long channel fires. 相似文献
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DZW6-1.57型锅炉使用三年后其烟管管端多次出现漏漏。对泄漏烟管的化学成分、显微组织和硬度,以及锅炉水质进行了检验,结果均属正常。通过分析,认为烟管管端泄漏是局部温差应力造成的。进水温度低且进水位置不当,破坏了水循环;省煤器阻塞,烟灰烟垢严惩,使烟气温度升高,造成管端产生温差应力,导致锅炉烟管管端频发泄漏事故。 相似文献
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为了获取室内装饰材料的火灾安全性,应用FDS火灾动力学仿真软件分别模拟了PVC(聚氯乙烯)、PMMA(聚甲基丙烯酸甲酯)、PS(聚苯乙烯)三种常用装饰材料的燃烧特性.模拟结果显示,PMMA材料初始燃烧速率最快,50s内近火源温度接近500℃,PS次之,PVC较为缓慢,但在500s内温度可达500℃以上;450s时PVC燃烧的过门热流量达到130kW,为三者最高;PVC材料初始产烟效果要弱于PMMA、PS两种材料,但70s后烟层高度下压趋势更为明显.模拟结果可以为室内消防设计及火灾现场人员的安全疏散提供参考依据. 相似文献