室内火灾过程的动力学响应性分析

根据小规模室内火灾试验的结果,利用动力学响应性分析的方法,研究室内火灾过程;初步探讨有关研究结果在实际消防工作中的应用.结果表明:动力学响应性分析为室内火灾过程的研究开辟了又一条新的途径,其研究结果可用于提出新的室内轰燃判据和确定热烟气层温度变化曲线方程.     

地下车库火灾烟气温度特性的数值模拟研究

利用火灾模拟软件FDS,根据地下汽车库实际尺寸建立了火灾模型,模拟了第275 s时引燃右侧据火源1 m处的车辆发生的轰燃现象。通过从不同层面对轰然前后空间温度的分析,探究了机械通风条件下车库火灾温度演化的规律。     

室内火灾轰燃判据的研究

１．引言所有封闭结构中的消防系统都应有火灾发生初期阶段（轰燃前）的早期报警和火灾控制措施。因此,了解轰燃的判据在消防工程中是非常重要的。此问题是利用热平衡方程式进行研究的。在方程式中,发生室内火灾时产生的热量与损失的热量之差决定了室内温度上升的速率。...     

室内火灾均一温度假设实验研究

通过小规模火灾实验,对多点温度进行统计分析。结果表明,在轰燃发生前和轰燃发生一段时间后,室内温度均一性较好,发生轰燃时,均一温度假设不成立。在此基础上提出温度分布均一性指数量化温度分布均一化程度,并认为其最小值对应的时间是轰燃发生时间。     

室内火灾轰燃研究的动态述评

在大量阅读中外文献的基础上，总结评述了目前国内外室内火灾轰燃研究的现状，包括轰燃形成的基本原因、轰燃发生临界条件、影响轰燃发生的主要因素以及这些因素对发生轰燃的影响机理等。     

室内火灾区域模拟及火灾各分模型的模化

简述区域模拟的基本原理,介绍区域模型模拟室内火灾的基本分析方法,给出轰燃前后室内火灾发展的质量、能量守恒方程,并阐述火灾模拟中四个子模型包括火源热释放速率、羽流、开口流、传热的数学模化理论,在具体应用中应合理假设并正确选择各子模型的模化方法,得出符合实际的室内火灾发展规律.     

可燃材料对室内火灾轰燃影响及应对措施

文章在简要介绍轰燃现象理论基础上,通过火灾试验箱研究了可燃材料对室内轰燃的影响.结果 表明,不同可燃材料的热解和燃烧特性、材料的燃烧面积及质量等因素对有限空间的轰燃都会产生影响,为消防救援队伍在处置建筑火灾过程中预防轰燃的发生提供参考.     

排烟量对室内火灾轰燃的影响

利用NIST开发的场模拟软件FDS，对室内火灾中排烟风机的排烟量对轰燃的影响情况进行模拟研究，探讨其变化规律，为建筑消防系统设计中排烟风机的选用和相关消防规范的制定提供参考。     

室内火灾危险性分析

利用FDS软件模拟火源在室内不同位置处火灾的危险性,分析火源在不同位置时室内烟气层的温度、氧气体积分数及烟气层高度的变化规律。模拟结果表明:火源在门开口径向方向时,室内1.5 m高度以下空间的烟气层温度较高,氧气体积分数较低,而1.5 m以上情况相反;火源位置距离开口越近,烟气层高度越低,危险性越大。     

室内可燃物性质对轰燃的影响

分别对有燃料和无燃料两种小尺寸燃烧室内进行验证实验,并采用点燃不同可燃物以及改变可燃物面积的实验方法,分析了室内可燃物性质对轰燃的影响因素,进而得出了一些有益的结论。     

Energy distribution analysis in full-scale open floor plan enclosure fires

Within a fast evolving built environment, understanding fire behaviour and the thermal exposure upon structural elements and systems is key for the continued provision of fire safe designs and solutions. Concepts of fire behaviour derived from research in enclosure fires has traditionally had a significant impact in general building design. At present, open floor plan enclosures are increasingly common – building design has drastically drifted away from traditional compartmentalisation. Nevertheless, the understanding of fire behaviour in open floor plan enclosures has not developed concurrently. The compartment fire framework, first conceived for under-ventilated fires in cubic compartments, has remained as standard practice. Although energy conservation within the enclosure was the basis for the current compartment fire framework that defines under-ventilated enclosure fires, little effort has been carried towards understanding the distribution of energy in design frameworks conceived for open floor plan enclosure fires. The work presented herein describes an analysis of the energy distribution established within an experimental full-scale open floor plan enclosure subjected to different fire modes and ventilation conditions. The results aim to enable the designer to estimate the fraction of the total energy released during a fire noteworthy to structural performance.     

A probabilistic risk analysis technique with an application to enclosure fires

A new technique for solving stochastic differential equations is described and illustrated by an application to a simple theory of enclosure fires. The relevance of this technique to the prediction of complex processes in accidental fires is discussed.     

Prediction of heat and smoke movement in enclosure fires

In order to understand the response of a detector to a given fire in an enclosure, it is necessary to relate the local thermal and aerosol characteristics actually sensed by the detector to the physical and geometrical properties of the fire and the enclosure. This paper presents computations designed to predict the evolution of the size distribution of smoke aerosol as it ages, as well as the large-scale air movement and temperature fields generated by an enclosure fire.

The computations contain three main ingredients: first, a finite difference solution for the air movement and temperature generated by a prescribed source of heat used to represent a fire in a closed form; second, the computer evaluation of an exact solution to the ageing equation correspond to the evolution of an experimentally observed size distribution; and third, a particle tracking scheme which permits the smoke aerosol to be followed in space and time as it gradually fills the room. No nonphysical empirical parameters (e.g. turbulence models) are employed in these calculations. The mathematical and physical models are summarized briefly, but most emphasis is placed on displaying results. Sample calculations are presented, comparisons are made with relevent experiments, and predictions of the local environment experienced by a detector due to the occurrence of an enclosure fire are shown.     

Grouping methods for MPS soot transport model and its application in large-scale enclosure fires

A soot transport model called Multi-Particle-Size model (MPS model) was developed to improve the prediction of soot movement by considering the uneven mass size distribution of soot particles and the influence of particle size on the gravitational settling. The model requires a sophisticated grouping method to divide the soot particles into several groups and determine the representative size for each group. In this paper, several soot particle grouping methods and the approach to calculate the representative sizes are developed with the aim of balancing the computational efficiency and the prediction accuracy of the model. The performance of the MPS model when different grouping methods are applied is investigated through the comparison of the predicted movement of soot particles generated from several materials. Based on this analysis a grouping method that results in the identification of three groups is shown to be sufficient to represent the influence of particle size on the gravitational settling for a variety of combustible materials and the computational cost of the extra governing equations for the transport of soot particles in the groups is acceptable. Furthermore, the efficiency of the model is demonstrated by simulating soot movement in a large-scale industrial building with a high ceiling.     

室内火灾旋转火焰理论分析与实验研究

根据涡量传输和火灾动力学等理论,分析室内火灾旋转火焰的形成机理,导出室内火灾产生旋转火焰的控制因素表达式。旋转火焰的产生需要足够的密度梯度、压力梯度和斜压效应。利用小规模室内火灾实验,研究室内火灾旋转火焰的基本特征,比较旋转与非旋转火焰火灾的基本参数。与非旋转火焰的室内火灾比较,旋转火焰室内火灾热烟气层温度、升温速率、燃烧速率、地板所受辐射热通量等的均值与峰值均有显著提高,且峰值出现较早。结合理论分析与实验研究结果,得到了室内火灾发生旋转火焰的条件判据。     

装饰材料对室内回燃特性的影响分析

选取几种典型建筑装饰材料,测试不同内衬材料热惯性下热烟气层温度、温升速率和回燃延迟时间等参数的变化,研究其对室内回燃特性的影响。     

室内火灾中非连续介质着火危险性影响因素

通过小规模火灾实验,研究火源大小、通风口尺寸、可燃物堆放高度、内衬材料等因素对室内火灾中非连续介质着火的影响,为防止室内火灾的蔓延扩大提供参考和指导。     

An experimental study of the rate of gas temperature rise in enclosure fires

Sixty-one experiments are reported using PMMA fuel in a small scale compartment with interchangeable lining materials and an adjustable vent. In this article, the hot gas temperature records (sampled every 5 s) are used to investigate correlations of peak hot gas temperature with first and second order gradients during fire growth. The results of one full-scale test were found to match critical conditions suggested by the small scale tests for ensuring or avoiding flashover. The results demonstrate the potential for using growth data to predict peak hazards from an in-fire dynamic assessment. The implications and work needed for practical application are briefly discussed.