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High-performance real-time fire detection and forecasting framework for industrial cables 用于工业电缆的高性能实时火灾探测和预测框架
IF 3.4 3区 工程技术 Q2 ENGINEERING, CIVIL Pub Date : 2024-07-16 DOI: 10.1016/j.firesaf.2024.104228
Wanfeng Sun, Haibo Gao, Cheng Li

In industrial scenarios, cable fires have always been the most common threat, and traditional fire detection systems often rely on a large number of sensors, and the detection range is very limited, and it is impossible to effectively predict the fire situation in time. In this paper, we propose a detection and prediction scheme for industrial cable fire, which breaks the limitations of the previous research on multi-sensor signal input, and highly couples the detection and prediction modules to realize fire prediction based on video image input only. In fire detection, we design an object detection model using HSV for flame feature enhancement based on YOLOv8, and in fire prediction aspect, we use iTransformer as a time series prediction model to mine the correlation between various parameters to predict the spread of fire. In the experiments, the average absolute percentage error of the flame detection model for the detection of flame height, width and longitudinal position was 3.49%–10.64 %, 2.45%–8.89 % and 1.61%–9.31 %, respectively, and the MAPE of the time series prediction model for the above three parameters was 11.18%–15.06 % and 4.35%–8.18 %, 3.37%–6.62 %.The results of the above experiments verify that the proposed model has the ability to quantitatively analyze the fire spread trend in the actual fire and help firefighters make decisions.

在工业场景中,电缆火灾一直是最常见的威胁,而传统的火灾探测系统往往依赖大量传感器,探测范围十分有限,无法及时有效地预测火情。本文提出了一种针对工业电缆火灾的检测和预测方案,打破了以往研究多传感器信号输入的局限性,将检测和预测模块高度耦合,实现了仅基于视频图像输入的火灾预测。在火灾检测方面,我们基于 YOLOv8 设计了使用 HSV 进行火焰特征增强的物体检测模型;在火灾预测方面,我们使用 iTransformer 作为时间序列预测模型,挖掘各种参数之间的相关性来预测火灾的蔓延。在实验中,火焰检测模型对火焰高度、宽度和纵向位置检测的平均绝对百分比误差分别为 3.49%-10.64 %、2.45%-8.89 % 和 1.61%-9.31 %,时间序列预测模型对上述三个参数的 MAPE 分别为 11.18%-15.06 %和4.35%-8.18 %、3.37%-6.62 %。上述实验结果验证了所提出的模型具有定量分析实际火灾中火势蔓延趋势的能力,有助于消防人员做出决策。
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引用次数: 0
Experimental study on the inertization of wood-based biomass with solid inerts 木质生物质与固体惰性物质惰性化实验研究
IF 3.4 3区 工程技术 Q2 ENGINEERING, CIVIL Pub Date : 2024-07-15 DOI: 10.1016/j.firesaf.2024.104223
Nieves Fernandez-Anez, Bjarne C. Hagen

Wood pellets are one of the primary solid substitutes for fossil fuels worldwide. They present both advantages and disadvantages that have been widely studied, where one of the main disadvantages is the risk of self-heating, which may lead to smouldering combustion or explosion. The risk of smouldering increases with decreasing particle size, while the difference in fire behaviour due to particle sizes needs to be studied in more detail. One of the techniques used to avoid, or decrease, the risk of smouldering is inertization. Inertization with gases is ineffective due to the difficulty gas has in accessing all voids in solid materials. An alternative solution is to use inert solids instead of gas.

This research empirically studies the fire behaviour of wood pellets and wood dust with particle size of less than 1 mm, and the influence of solid inertization in both materials in two different configurations: mixed and layered. The ignition initiation of both particle sizes is similar, while the cool-down phase is quicker in the case of dust. However, inertization of dust needs a significantly higher amount of inert solids than in the case of pellets, being easier to avoid smouldering when the inerts are disposed in layers rather than mixed with the materials.

木质颗粒是全球化石燃料的主要固体替代品之一。它们的优点和缺点都已被广泛研究,其中一个主要缺点是有自热的风险,可能导致闷烧或爆炸。烟熏的风险随着颗粒大小的减小而增加,而颗粒大小导致的火灾行为差异还需要更详细的研究。惰化是避免或降低烟熏风险的技术之一。由于气体难以进入固体材料的所有空隙,因此使用气体惰化的效果不佳。本研究对粒径小于 1 毫米的木粒和木粉的燃烧行为进行了实证研究,并研究了两种不同结构(混合结构和分层结构)的固体惰化对这两种材料的影响。两种粒度的起火过程相似,而粉尘的冷却阶段更快。不过,粉尘的惰性化所需的惰性固体量明显高于颗粒,当惰性物质分层放置而不是与材料混合时,更容易避免烟熏。
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引用次数: 0
Study on the plume flow behavior and air entrainment characteristics of co-burning fires 共燃火灾的烟流行为和空气夹带特性研究
IF 3.4 3区 工程技术 Q2 ENGINEERING, CIVIL Pub Date : 2024-07-09 DOI: 10.1016/j.firesaf.2024.104211
Qineng Zhou, Chen Wang, Haowei Hu, Weixin Tong, Jingbo Xu, Jie Ji

In most of the fire accidents, there is large oil layer leaking into the fire dike and multiple fire points burning simultaneously. A series of numerical simulations for co-burning of a dike and double tanks (co-burning) with different spacing S have been conducted to study the plume flow behavior and air entrainment characteristics. The simulation results show that there is a conical fuel-rich region on the upper rim of the tank which results in the entrained air to flow circularly along the surface of the conical region. With the increase of S, the restriction effect of tank sidewall on air entrainment from environment enhances, while the restriction degree of air entrainment in the middle area of the double tanks decreases, affecting the distribution of plume velocity field and temperature field. And under the coupling effect of them, the tilt degree of tank flame decreases with the increase of S (from 0.3 m to 0.7 m). The air entrainment restriction coefficient αB, αS are introduced to characterize the restriction effect of air entrainment between the external dike fire and the double tank fires. Based on this, a co-burning plume entrainment model has been established, which can be applicable to different spacing S.

在大多数火灾事故中,都会有大量油层渗漏到防火堤中,并有多个着火点同时燃烧。我们对不同间距 S 的堤坝和双油罐(共同燃烧)进行了一系列数值模拟,以研究烟流行为和空气夹带特性。模拟结果表明,罐体上缘存在一个锥形富燃料区,导致夹带的空气沿锥形区表面环流。随着 S 的增大,油箱侧壁对环境夹带空气的限制作用增强,而双层油箱中间区域对夹带空气的限制程度减小,从而影响烟流速度场和温度场的分布。在二者的耦合作用下,随着 S 的增大(从 0.3 米到 0.7 米),水箱火焰的倾斜度减小。引入空气夹带限制系数 αB、αS 来表征外堤火与双罐火之间的空气夹带限制效应。在此基础上,建立了可适用于不同间距 S 的共燃烟羽夹带模型。
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引用次数: 0
Corrigendum to “Simulation of a premixed explosion of gas vented during Li-ion battery failure” [Fire Saf. J. 126 (2021) 103478] 对 "模拟锂离子电池故障时排出气体的预混合爆炸 "的更正 [Fire Saf. J. 126 (2021) 103478]
IF 3.4 3区 工程技术 Q2 ENGINEERING, CIVIL Pub Date : 2024-07-06 DOI: 10.1016/j.firesaf.2024.104208
Mathias Henriksen , Knut Vaagsaether , Joachim Lundberg , Sissel Forseth , Dag Bjerketvedt
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引用次数: 0
Effect of the Al/Si ratio on intumescent Na-based geopolymer 铝/硅比对膨胀型 Na 基土工聚合物的影响
IF 3.4 3区 工程技术 Q2 ENGINEERING, CIVIL Pub Date : 2024-07-04 DOI: 10.1016/j.firesaf.2024.104220
Qi Yang , Catherine A. Davy , Johan Sarazin , Serge Bourbigot , Gaëlle Fontaine

This research investigates the fire resistance properties of alkali activated Na-based geopolymers (GP), used as steel protective coatings. The effect of different Al/Si molar ratios (0–0.54) is evaluated fire test. When coated on a steel plate, GP having the smaller Al/Si ratio exhibits an intumescent behavior with the highest expansion. When Al/Si = 0, the temperature at the backside of the steel plate is 313 °C which is decreased by 347 °C compared to an uncoated steel plate (660 °C). After fire testing, the GP physico-chemical properties are characterized with optical microscopy, Electron probe micro-analysis, dynamic mechanical analysis. According to stiffness test results, when the temperature approaches 100 °C, the GP with a given Al/Si ratio (different from zero) softens and expands (intumescence). The greater the Al/Si ratio in the GP, the more rigid the structure; this phenomenon limits expansion, and hence, lowers the fire protection.

本研究调查了用作钢铁保护涂层的碱活化 Na 基土工聚合物 (GP) 的耐火性能。在火灾试验中评估了不同铝/硅摩尔比(0-0.54)的影响。在钢板上涂覆时,铝/硅比率较小的 GP 表现出膨胀性最高的膨胀行为。当 Al/Si = 0 时,钢板背面的温度为 313 °C,与未涂层钢板(660 °C)相比降低了 347 °C。火灾测试后,使用光学显微镜、电子探针显微分析和动态机械分析对 GP 的物理化学特性进行了表征。根据刚度测试结果,当温度接近 100 ℃ 时,特定铝/硅比(不同于零)的 GP 会变软并膨胀(膨胀)。GP 中的铝/硅比越大,结构就越坚硬;这种现象限制了膨胀,从而降低了防火性能。
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引用次数: 0
Large-scale fire experiments in a cross-laminated timber compartment with an adjacent corridor – Partly and fully protected with a water sprinkler system 在带邻近走廊的交叉层压木隔间内进行大规模火灾实验 - 部分和全部采用水喷淋管道系统进行保护
IF 3.4 3区 工程技术 Q2 ENGINEERING, CIVIL Pub Date : 2024-07-03 DOI: 10.1016/j.firesaf.2024.104212
Andreas Sæter Bøe , Kristian Hox , Ragni Fjellgaard Mikalsen , Kathinka L. Friquin

Two fire experiments have been conducted to study sprinkler system extinguishing performance in a compartment (13 m2) with an adjacent corridor (12 m2), both with exposed cross-laminated timber (CLT). Four nozzles were installed in the corridor and two in the compartment. In Experiment 1, the sprinkler system was fully functional and successfully controlled a concealed fire. In Experiment 2, nozzles in the compartment were disconnected, while the corridor nozzles were operative, giving flashover after 5 min with large flames emerging into the corridor, rapidly worsening evacuation conditions. Despite four activated nozzles in the corridor, the temperatures remained high, and flames spread through the corridor along the CLT ceiling and the upper parts of the wall, an area that was not effectively protected by the nozzles. After flashover, the compartment temperatures remained stable at ∼1000 °C until experiment termination at 96 min. This continued fire in the compartment can be explained by water from the corridor sprinklers not reaching this area, extensive radiative feedback by the CLT surfaces and delamination of CLT elements of the 20 mm layers. The charring rate was ≥1.1 mm/min for large parts of the exposed CLT wall and ceiling in the compartment during the fire.

为了研究喷水灭火系统的灭火性能,我们进行了两次火灾试验,试验地点是一个隔间(13 米)和一个相邻的走廊(12 米),这两个隔间都有裸露的交叉层压木材(CLT)。走廊安装了四个喷嘴,隔间安装了两个喷嘴。在实验 1 中,自动喷水灭火系统功能齐全,成功控制了一场隐蔽火灾。在实验 2 中,隔间中的喷头断开,而走廊中的喷头正常工作,5 分钟后出现闪燃,大面积火焰涌入走廊,迅速恶化了疏散条件。尽管走廊的四个喷嘴都已启动,但温度仍然很高,火焰沿着 CLT 天花板和墙壁上部(喷嘴无法有效保护的区域)蔓延到走廊。闪燃后,隔间温度稳定在 1000 °C,直到 96 分钟实验结束。车厢内持续起火的原因可能是走廊喷淋器的水没有喷到这一区域、CLT 表面产生大量辐射反馈以及 20 毫米层的 CLT 元件脱层。火灾期间,隔间中大部分暴露在外的 CLT 墙壁和天花板的炭化速度≥1.1 毫米/分钟。
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引用次数: 0
Influence of upstream blockage on smoke control in tunnel fires 上游堵塞对隧道火灾烟雾控制的影响
IF 3.4 3区 工程技术 Q2 ENGINEERING, CIVIL Pub Date : 2024-07-01 DOI: 10.1016/j.firesaf.2024.104197
Ying Zhen Li, Haukur Ingason

Smoke control in a longitudinally ventilated tunnel with various blockage conditions was investigated experimentally. A total of 28 tests were conducted with a focus on single blockage with a short distance from the fire source, although continuous blockage and semicontinuous blockage were also discussed. Both gas and pool fires were used. The aim was to understand the influence of upstream blockage on critical velocity and babcklayering length. The results confirm that blockage ratio is a critical parameter when determining the critical velocity and backlayering length. The longitudinal location of the blockage in relation to the fire source also influences the values of critical velocity and backlayering length. The experiments presented are in scale 1 to 3.3, representing a medium sized tunnel. The focus was on free flow conditions and blockage ratios of regular sizes. For the various tested scenarios with single blockage, the reduction ratio of critical velocity appears to be slightly less than the blockage ratio. However, when the blockage is attached to the upstream side of the fire source, the reduction ratio of critical velocity approximately equals the blockage ratio.

实验研究了各种堵塞条件下纵向通风隧道的烟雾控制情况。共进行了 28 次测试,重点是与火源距离较近的单一阻塞,但也讨论了连续阻塞和半连续阻塞。试验中使用了气火和池火。目的是了解上游堵塞对临界速度和 babcklayering 长度的影响。结果证实,在确定临界速度和背层长度时,阻塞率是一个关键参数。堵塞物相对于火源的纵向位置也会影响临界速度和背压长度的值。所展示的实验规模为 1 到 3.3,代表了一个中等规模的隧道。重点是自由流动条件和规则尺寸的堵塞率。在单个堵塞物的各种测试方案中,临界速度的降低率似乎略低于堵塞率。然而,当堵塞物附着在火源的上游侧时,临界速度的降低率近似等于堵塞率。
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引用次数: 0
Shrinkage characteristics of glass and mineral fibre insulation materials at elevated temperatures 玻璃纤维和矿物纤维绝缘材料在高温下的收缩特性
IF 3.4 3区 工程技术 Q2 ENGINEERING, CIVIL Pub Date : 2024-07-01 DOI: 10.1016/j.firesaf.2024.104210
Linbo Zhang, Mohamed A. Sultan

The fire resistance of building assemblies can be determined through testing or by numerical modelling. As testing of building assemblies is expensive and time-consuming, the development of numerical modelling methods is gaining momentum. One of the challenges in modelling assemblies’ thermal performance is insulation dimensional shrinkage at elevated temperatures. To address this challenge, this paper presents a comprehensive experimental investigation into the shrinkage of glass and mineral fibre insulation materials under elevated temperature conditions. Initially, a series of tests was conducted to establish the temperature range within which significant shrinkage occurs for both types of insulation. Then, visual observations and measurements were recorded to assess the physical and dimensional changes of the insulation materials within the identified temperature range for shrinkage, indicating distinct responses of glass and mineral fibre insulation to thermal exposure. Compared to width and length variations, thickness reduction in insulation was more significant. Overall, the insulation thickness decreased as the exposed temperature increased. The glass fibre insulation completely melted at 710 °C, while mineral fibre insulation disintegrated at 1000 °C. In addition, empirical equations were derived to assess the thickness variations of these insulations at elevated temperatures, which can greatly enhance the accuracy of future thermal models under fire scenarios. Lastly, potential areas for future research are identified.

建筑组件的耐火性能可以通过测试或数值模拟来确定。由于对建筑组件进行测试既昂贵又耗时,因此数值建模方法的发展势头日益强劲。模拟装配式建筑热性能的挑战之一是保温材料在高温下的尺寸收缩。为了应对这一挑战,本文对玻璃纤维和矿物纤维保温材料在高温条件下的收缩情况进行了全面的实验研究。首先,进行了一系列测试,以确定两种隔热材料发生明显收缩的温度范围。然后,通过目视观察和测量记录,评估绝缘材料在确定的收缩温度范围内的物理和尺寸变化,结果表明玻璃纤维和矿物纤维绝缘材料对热暴露的反应截然不同。与宽度和长度变化相比,隔热材料厚度的减少更为显著。总体而言,隔热材料的厚度随着暴露温度的升高而减小。玻璃纤维隔热材料在 710°C 时完全熔化,而矿物纤维隔热材料在 1000°C 时解体。此外,还得出了经验方程来评估这些隔热材料在高温下的厚度变化,这可以大大提高未来火灾情况下热模型的准确性。最后,确定了未来研究的潜在领域。
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引用次数: 0
Operational uptime and other measures of performance of an open car park in fire 消防开放式停车场的正常运行时间和其他性能指标
IF 3.4 3区 工程技术 Q2 ENGINEERING, CIVIL Pub Date : 2024-06-28 DOI: 10.1016/j.firesaf.2024.104209
Wojciech Węgrzyński, Paulina Jamińska-Gadomska, Bartosz Miechówka, Grzegorz Krajewski

192 coupled wind and fire CFD simulations were performed using ANSYS Fluent to study the wind and fire interaction in an open car park. The natural ventilation was insufficient for removal of smoke and heat for the majority of investigated fires. Blockage effect was observed for wind directions parallel to the open walls, which resulted in reduced smoke removal and higher smoke temperatures. With known probabilities of all the investigated wind speed and directions, we have estimated the percentage of time in which fire outcomes are acceptable. This value was coined as the car park operational uptime, and was 84.9 %–92.8 % in relation to the fire with HRR = 1.4 MW; 36.5 %–56.1 % at 4.0 MW; 34.1 %–54.4 % at 6.0 MW and 12.13–25.5 % at 8.8 MW. In 6.22 % of wind cases, the velocity inside the car park exceeded 3.0 m/s, which could potentially contribute to the growth of the fire. Limitations of the study include the assumed wind probability distribution relevant to the Warsaw region, the single location of the fire used in the assessment and the implicit modelling of topography and architecture through an introduced wind profile and terrain roughness model.

使用 ANSYS Fluent 进行了 192 次风与火 CFD 耦合模拟,以研究开放式停车场中风与火的相互作用。在大多数调查的火灾中,自然通风不足以消除烟雾和热量。与开放式墙壁平行的风向会产生阻塞效应,导致排烟量减少和烟雾温度升高。根据所有调查风速和风向的已知概率,我们估算出火灾结果可接受的时间百分比。该值被称为停车场运行正常时间,在 HRR = 1.4 MW 的情况下为 84.9 %-92.8 %;在 4.0 MW 的情况下为 36.5 %-56.1 %;在 6.0 MW 的情况下为 34.1 %-54.4 %;在 8.8 MW 的情况下为 12.13-25.5 %。在 6.22% 的风力情况下,停车场内的风速超过了 3.0 米/秒,这有可能导致火势蔓延。该研究的局限性包括:假定的风力概率分布与华沙地区相关、评估中使用的火灾地点单一以及通过引入风廓线和地形粗糙度模型对地形和建筑进行隐式建模。
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引用次数: 0
On the Nusselt number correlations of tandem surrogate firebrands on a flat surface 关于平面上串联替代火带的努塞尔特数相关性
IF 3.4 3区 工程技术 Q2 ENGINEERING, CIVIL Pub Date : 2024-06-28 DOI: 10.1016/j.firesaf.2024.104207
Savannah S. Wessies, Jiann C. Yang

Through the heat-mass transfer analogy, naphthalene sublimation experiments were conducted in a heated-air wind tunnel to study the effects of aspect ratio and dimensionless separation distance on the convective heat transfer coefficients of three tandem naphthalene cylinders. Nusselt number correlations were presented for the individual naphthalene cylinders and the full configuration of three cylinders. In all the cases studied, the Reynolds number had the strongest effect on the Nusselt number followed by the aspect ratio and the dimensionless separation distance. Nusselt numbers were higher for the smaller aspect ratios. For a given Reynolds number and aspect ratio, the Nusselt number increases with the dimensionless separation distance.

通过热质传递类比,在加热空气风洞中进行了萘升华实验,研究了高宽比和无量纲分离距离对三个串联萘圆柱体对流传热系数的影响。研究给出了单个萘气缸和三个气缸完整配置的努塞尔特数相关性。在所有研究案例中,雷诺数对努塞尔特数的影响最大,其次是长宽比和无量纲分离距离。纵横比越小,努塞尔特数越高。对于给定的雷诺数和纵横比,努塞尔特数随无量纲分离距离的增加而增加。
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引用次数: 0
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Fire Safety Journal
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