纵向通风下坡度隧道火灾烟气特性数值模拟研究

为探讨纵向通风情况下坡度隧道火灾烟气的温度分布、回流长度等特性参数,运用火灾动力学模拟软件FDS建立一个长为500 m的公路隧道模型,对不同坡度、不同纵向通风速率的20组火灾工况进行模拟研究,通过分析各工况的模拟结果,并结合前人在隧道火灾烟气特性研究方面的成果,得到火灾情况下隧道内烟气的纵向温度分布规律、隧道拱顶温度变化规律、温度偏移及烟气回流长度变化规律等。     

Multi-factor principle for electrolyte additive molecule design for facilitating the development of electrolyte chemistry

When I read the paper"Electrolytes enriched by potassium perfluorinated sulfonates for lithium metal batteries"from Prof. Jianmin Ma's group, which was published in Science Bulletin (doi.org/10.1016/j.scib.2020.09.018), I felt excited as presented a multi-factor principle for applying potassium perfluorinated sulfonates to suppress the dendrite growth and protect the cathode from the viewpoint of electrolyte additives. The effects of these additives are revealed through experimental results, molecular dynamics simulations and first-principle calculations. Specifically, it involves the influence of additives on Li+ solvation structure, solid electrolyte interphase (SEI), Li growth and nucleation. Following the guidance of the multi-factor principle, every part of the additive molecule should be utilized to regulate electrolytes. This multi-factor principle for electrolyte additive molecule design (EAMD) offers a unique insight on understanding the electrochemical behavior of ion-type electrolyte additives on both the Li metal anode and high-voltage cathode. In these regards, I would be delighted to write a highlight for this innovative work and, hopefully, it may raise more interest in the areas of electrolyte additives.     

喷射火对输油管道热影响实验平台设计与验证*

为研究油气并行管道中,天然气管道喷射火对相邻输油管道内流体与管壁的热影响,设计并搭建天然气喷射火对输油管道热影响实验平台。实验平台由环道及冷却系统、火焰系统、控制及数据采集系统3个部分组成。完成平台搭建并验证环道系统气密性后,以0#柴油为介质,开展验证实验。研究结果表明:火焰系统工作可靠且可控,冷却系统能够将柴油温度控制在初馏点以下,数据采集系统能够正常采集油品压力、温度、流量、管壁温度、火焰温度等预定数据,实验平台具备一定可行性与安全性。实验平台可进行在不同管道规格及材质、火灾形式、油品介质及流速条件下的热影响实验。实验平台结合材料性能进行测试,可研究喷射火对管材性能的影响,为油气并行管道的安全运行提供相关实验依据。     

不同聚合度的聚磷酸铵灭火性能研究*

为考察聚磷酸铵（APP）干粉灭火剂的聚合度对其灭火性能的影响,选用3种不同聚合度的APP,结合其晶体结构、粒度分布及热性能测试,并通过粉体杯式燃烧器进行小尺寸灭火实验,对比3种样品的灭火性能及灭火机理,研究聚合度与其灭火性能的关系。热性能测试结果显示,聚合度的升高会导致APP的热稳定性下降,随着聚合度从80升至1 500,其初始分解温度从326.11 ℃降低至321.54 ℃,失重率从75.21%增加至79.66%。实验结果表明:随着APP聚合度的增加,火焰降温速率升高,最小灭火浓度（MEC）降低,灭火性能增强,当聚合度为1 500时,MEC为118.143 g/m3。聚合度的升高有助于APP在进入火场后更早、更充分地与火焰发生反应,从而使灭火性能得到提升。     

初始扰动对CO2抑制瓦斯爆炸特性研究*

为了预防实际生产过程中发生的瓦斯爆炸事故,利用20 L球形爆炸装置,通过改变粉尘仓充压压力产生不同的扰动,研究9.5%CH4浓度下不同扰动条件对CO2抑爆特性的影响。通过对所得参数进行分析,得到CO2抑爆特性与初始扰动的关系。研究结果表明:相较于均匀静置状态,初始扰动的存在均能提高CH4的爆炸强度,当引发初始扰动的粉尘仓压力为1.5 MPa时,最大爆炸压力达到0.78 MPa;随CO2浓度增大,爆炸强度整体下降,呈二次下降趋势、最大爆炸压力时间呈上升趋势,且各初始扰动压力间爆炸强度均大于均匀静置状态、最大爆炸压力时间小于均匀静置状态;同时利用CHEMKIN软件得到绝热平衡压力,计算热损失参数发现,同一气体混合比例工况下,初始扰动状态的热损失及热损失分数明显低于均匀静置状态的,且当CO2浓度为15%时,差距最大,不同初始扰动间热损失及热损失分数最小值分别为0.013 19 kJ/m2,17.9%,远小于静置状态下0.036 29 kJ/m2,46.4%,说明初始扰动对于CO2抑爆效果存在削弱作用。     

面向设计的地铁车站防火安全韧性评价*

为提升地铁车站防火安全韧性,以设计方案为切入视角,基于防火安全韧性的吸收、抵抗、恢复和适应能力4个维度,构建基于ANP-熵权法面向设计的地铁防火安全韧性评价指标体系,运用逼近理想解法建立地铁车站防火安全韧性设计评价模型,通过3个已建地铁车站（青岛、沈阳、福州某地铁车站）的设计案例验证该模型的有效性和可行性。研究结果表明:3个应用案例中,沈阳某地铁车站设计防火安全韧性最高,福州某地铁车站设计防火安全韧性最低,需进一步提升防火安全能力。评价结果与各案例的实际运行阶段基本吻合,研究思路和结果对改善地铁车站的防火安全设计具有一定参考意义。     

城市火险预警等级中的火灾次数分布模拟

本文根据对南京市多年火灾次数的分析，提出可利用泊松分布对不同火险预警等级中的火灾次数进行模拟的设想，从而使城市火险预警的内容得到进一步扩展。     

Conservation Threats Due to Human-Caused Increases in Fire Frequency in Mediterranean-Climate Ecosystems

Periodic wildfire is an important natural process in Mediterranean-climate ecosystems, but increasing fire recurrence threatens the fragile ecology of these regions. Because most fires are human-caused, we investigated how human population patterns affect fire frequency. Prior research in California suggests the relationship between population density and fire frequency is not linear. There are few human ignitions in areas with low population density, so fire frequency is low. As population density increases, human ignitions and fire frequency also increase, but beyond a density threshold, the relationship becomes negative as fuels become sparser and fire suppression resources are concentrated. We tested whether this hypothesis also applies to the other Mediterranean-climate ecosystems of the world. We used global satellite databases of population, fire activity, and land cover to evaluate the spatial relationship between humans and fire in the world's five Mediterranean-climate ecosystems. Both the mean and median population densities were consistently and substantially higher in areas with than without fire, but fire again peaked at intermediate population densities, which suggests that the spatial relationship is complex and nonlinear. Some land-cover types burned more frequently than expected, but no systematic differences were observed across the five regions. The consistent association between higher population densities and fire suggests that regardless of differences between land-cover types, natural fire regimes, or overall population, the presence of people in Mediterranean-climate regions strongly affects the frequency of fires; thus, population growth in areas now sparsely settled presents a conservation concern. Considering the sensitivity of plant species to repeated burning and the global conservation significance of Mediterranean-climate ecosystems, conservation planning needs to consider the human influence on fire frequency. Fine-scale spatial analysis of relationships between people and fire may help identify areas where increases in fire frequency will threaten ecologically valuable areas.     

哈龙固定灭火系统替代技术

介绍了哈龙固定灭火系统淘汰背景,哈龙灭火系统替代技术发展现状。结合消除建审工作经验,阐述了作为哈龙替代系统且目前在国内工程实践中应用的CO2灭火系统、INERGEN灭火系统、FM-200灭火系统及EBM灭火系统主要性能及与哈龙系统的差异,探讨哈龙替代系统技术发展趋势,对气体灭火系统设计选型有一定参考价值。     

细水雾抑制障碍物稳定火焰的实验研究

采用模拟实验的方法 ,研究了细水雾对障碍物后隐藏火焰的抑制效果。实验发现 :对于水平方向施加水雾 ,能够有效地抑制火焰。通过与哈龙灭火剂灭火有效性进行对比 ,发现在有障碍物时 ,细水雾灭火效率尚待提高