浅谈计算机数值模拟在分析火灾烟气流动中的运用

本文就计算机数值模拟在火灾烟气流动的分析、运用做了某些尝试,以期达到抛砖引玉的作用,促进计算机模拟在消防工作中的运用和发展。     

某重大火灾的计算机数值模拟分析

利用FDS软件对某重大火灾进行数值模拟,对四种设置不同消防设施状态进行火场温度、烟气能见度、可用安全疏散时间的对比分析,并结合CFE软件进行火场疏散过程模拟,对不同疏散人数时的预期人员伤亡进行分析。     

计算机模拟重构技术在火灾调查中的应用

随着信息技术的不断发展，计算机模拟在火灾调查中的应用日益受到关注。本文简要回顾了火灾过程计算机模拟的数学基础和三种不同层次的模拟方法，分析讨论了不同模拟方法在火灾调查应用中的优缺点。重点介绍了先进的场模拟方法并给出了实例。实践证明，采用计算机模拟的辅助火灾调查技术不仅可以提供理论支持，还可以提供科学数据。以协助火灾事故调查的进行。计算机模拟技术作为火灾调查的一种新方式无疑具有重要的发展价值。     

室内火灾的计算机模拟

本文采用区域模拟的方法,把火灾房间内的气体分为热层和下层冷空气分别考虑。建立了具有通风口的单室火灾发展的数学物理模型。数值计算结果与实验数据对比表明,理论预言与实际情况吻合相当好。     

计算机模拟在火灾事故树分析中的应用

本文介绍了事故树分析的基本原理,设计了一整套火灾事故树分析与计算程序。通过对实际火灾的分析与评价,取得了较好的应用效果。     

建筑室内火灾及其计算机模拟

简述了建筑室内火灾的发展过程及利用计算机对建筑室内火灾进行模拟的方法,探讨了近年来常用的计算机模型,表明了火灾科学与计算机技术的结合是火灾科学发展的必然趋势。     

某医院病房火灾危险性数值模拟分析

以区域模拟软件CFAST为工具,分析了某医院住院楼的火灾危险性。在确定了最不利着火楼层和着火房间后,通过比较不同房间着火时烟气层温度、空气层温度、烟气层界面高度以及CO浓度这4项指标,判定整栋住院楼人员能否安全疏散。所得结果表明,CFAST软件在评估类似规则空间建筑的火灾安全性方面,具有一定参考价值。     

火灾计算机模拟技术发展现状浅析

随着计算机科学和数值计算方法的发展,人们开始运用火灾计算机模型直接求解描述火灾过程的数学方程,这种结果有助于人们更深入、更全面地了解火灾过程.介绍了火灾模拟软件的发展及几款常用的软件,并针对我国火灾模拟发展状况提出了一些建议.     

电缆隧道火灾分析及计算机模拟

对电缆隧道火灾进行了分析,应用火灾动力学模拟软件FDS对电缆隧道火灾过程进行了计算机模拟,并对其火灾发展过程和防火保护措施进行了初步讨论。结果表明,电缆隧道为高火灾危险场所,在火灾情况下,隧道内维持较高温度,电缆将持续燃烧,火灾具有发展迅速、结构可能严重损伤、烟气量大、有害气体浓度高、扑救困难等特点,对其火灾危害性应引起足够重视。     

Fire situation and fire characteristic analysis based on fire statistics of China

This paper describes the fire situation of China in 1998. Fire statistics data have been analyzed with a view to understand the characteristics of fire accidents, including vocation and location distribution, cause analysis, monthly frequency and frequency of fires by time of day etc. It is revealed that specific work on fire protection should be taken so as to meet the demands of the society. In addition, some of the major fire accidents are also recapitulated briefly. Finally, the study highlights the importance to carry out fire statistics and gives some suggestions.     

A numerical approach for modeling the fire induced restraint effects in reinforced concrete beams

In this paper, a model to predict the influence of fire induced restraints on the fire resistance of reinforced concrete (RC) beams is presented. The three stages, associated with the fire growth, thermal and structural analysis, for the calculation of fire resistance of the RC beams are explained. A simplified approach to account for spalling under fire conditions is incorporated into the model. The validity of the numerical model is established by comparing the predictions from the computer program with results from full-scale fire resistance tests. The program is used to conduct two case studies to investigate the influence of both the rotational and the axial restraint on the fire response of the RC beams. Through these case studies, it is shown that the restraint, both rotational and axial, has significant influence on the fire resistance of the RC beams.     

Experimental investigation and numerical simulation of a furnished office fire

Experiments were conducted in a full-scale model room equipped with both movable and fixed fire loads to explore fire growth and spread via heat release rates, indoor air temperature and species concentration. The room space is a brick structure that measures 5.7 m in interior length, 4.7 m in width and 2.4 m in ceiling height. The northeast and southeast corners each feature a 2.1 m × 0.9 m open doorway. Numerical simulations with parameter adaptation were carried out using FDS software to predict the fire features and were compared with the experimental results. In this study, the material properties and oxygen limit settings in the FDS software were tested to explore their influence on the tendency of heat release rate and on the total amount of heat release. The results show that the heat release rate from the FDS simulations is comparable to the full-scale experiment results during the fire growth period. Temperature profile near ceiling can be modeled well. In the full-involvement burning and decaying periods, the qualitative trends were identical, although the simulated value differed greatly from the experimental result.     

On the use of global sensitivity analysis for the numerical analysis of permeable pavements

The aim of this study is to investigate the use of different global sensitivity analysis techniques in conjunction with a mechanistic model in the numerical analysis of a permeable pavement installed at the University of Calabria. The Morris method and the variance-based E-FAST procedure are applied to investigate the influence of soil hydraulic parameters on the pavement’s behavior. The analysis reveals that the Morris method represents a reliable computationally cheap alternative to variance-based procedures for screening important factors and provides the first inspection of the model. The study is completed by a combined GSA-GLUE uncertainty analysis used to evaluate the model accuracy.     

A prototype methodology for fire hazard analysis

The first version of a method for predicting the hazards to occupants involved in a building fire is described. The method and available computer software, called HAZARDI, can predict the time varying environment within a building resulting from a specified fire; the locations and actions of occupants; and the impact of the exposure of each of the occupants to the fire products in terms of whether the occupants successfully escape, are incapacitated, or are killed.This paper is a contribution of the U.S. National Institute of Standards and Technology (formerly National Bureau of Standards) and is not subject to copyright.     

试析火灾痕迹在火灾事故调查中的应用

在进行火灾事故调查时,火灾痕迹是重要线索,火灾痕迹为调查人员提供了客观事实,帮助调查人员了解火灾事故起因.文章运用调查法、文献法等对火灾痕迹类型进行分析,并就火灾痕迹在火灾事故调查中的应用做具体探究,希望能为相关实践工作提供些许理论参考.     

Modeling of bolted angle connections in fire

Recent structural collapses caused by fire have focused attention on research concerning fire safety in building design. The high cost of experimental tests and limitations in the number of geometrical and mechanical parameters, in addition to advances in numerical methods that provide the ability to simulate complicated structures with numerous parameters, make the finite element method an attractive device for modeling the behavior of structural connections in fire.     

Nonlinear analysis of reinforced concrete cross-sections exposed to fire

A nonlinear structural analysis of cross-sections of three-dimensional reinforced concrete frames exposed to fire is presented. The analysis includes two steps: the first step is the calculation of the transient temperature field in cross-sections exposed to fire and the second step is the determination of the mechanical response due to the effect of thermal and mechanical load. A nonlinear finite-element procedure is proposed to predict the temperature field history. In this thermal analysis, the effect of moisture has been taken into account by introducing a water vapor fraction function to define the variation of enthalpy. A mechanical nonlinear analysis of the cross-sections is performed for each temperature distribution and for the applied exterior load using an algorithm of arc-length control. The mechanical and thermal properties of concrete and steel are taken according to the European Standard ENV 1991-1-2 [ENV. Eurocode 2, design of concrete structures, part 1–2: general rules—structural fire design. ENV 1992-1-2, 1995]. In order to validate the proposed thermal and mechanical models, comparisons between numerical and experimental results have been performed. The agreement found is in both cases, fairly good. In addition, a numerical example of the structural analysis of several cross-sections of a reinforced concrete waffle slab under external load and fire is shown.     

Dynamic modeling of fire spread in building

Modeling fire spread in a building is a key factor of a fire risk analysis used for fire safety designs of large buildings. In this paper, a dynamic model of fire spread considering fire spread in both horizontal and vertical directions is described. The algorithms for simulating the fire spread process in buildings and calculating dynamic probability of fire spread for each compartment at each time step of simulation are proposed. The formulae used in calculating the input data for the dynamic fire spread model are derived. The dynamic fire spread model can easily be applied for any building including high-rise buildings. A detailed example of calculation of fire spread in a two-storey office building is described.