【作者】 郑斌；

【导师】 陈国华；

【作者基本信息】 华南理工大学 ， 化工过程机械， 2011， 博士

【摘要】 化工储罐火灾影响因素众多,过程所涉及的危险因素、事故机理复杂,火灾现场破坏严重,往往给火灾现场勘查和起火点认定带来很大困难。在目前我国火灾事故调查证据单薄,说服力不强,物证分析技术匮乏的现状下,研究化工储罐火灾事故起火点推断物证技术,建立一套包括科学的调查取证手段、系统的推理方法和数值模拟仿真技术在内的火灾调查和物证分析技术体系,将有助于准确、快速分析火灾事故的起火点和原因,克服以往经验分析法的不足,提高火灾调查工作的科学性和可靠性。本文以化工储罐为具体研究对象,采用典型案例剖析、理论分析、实验测试以及模拟仿真相结合的研究手段,分析化工储罐火灾特点与破坏机理,建立化工储罐火灾模拟实验平台,研究化工储罐火灾的燃烧特性与典型物证的形成机理,分析面向起火点认定的储罐火灾数值模拟技术,建立化工储罐火灾起火点推断的定性和定量判据。主要研究内容如下:(1)化工储罐火灾特点与破坏机理。在总结化工储罐火灾特点的基础上,对近30年来我国发生的50起典型化工储罐火灾事故进行统计分析,从事故调查角度找出事故中共性的规律和特点,总结化工储罐火灾事故的典型类型;分析化工储罐火灾对外界物体产生破坏的主要形式,研究储罐周围物体在两种传热方式下温升的理论模型,分析化工储罐火灾中的物体在火焰内部和火焰外部不同的破坏机理。(2)化工储罐火灾燃烧特性的模拟实验研究。建立小尺寸柴油储罐火灾实验平台,采用接触和非接触两种方式对储罐火灾的火焰温度、火焰辐射、火焰高度、火焰形状等特征参量进行测量,分析火灾发展历程与扬沸现象,建立火灾高度-温度,火灾持续时间-火焰温度以及火焰温度-热辐射的关系,得到化工储罐火灾在不同燃烧时期的温度场和辐射场分布。研究液位高度、含水层、油层厚度、油品初温、消防射水等因素对火焰温度的影响,分析储罐火灾事故过程的灾害特性规律。(3)化工储罐火灾的典型物证及其形成机理。构建化工储罐火灾事故的物证体系,实验研究在模拟火灾环境中Q345R、Q245R和Q235R等典型物证的力学性能与火灾作用时间、火灾温度的关系;研究温升速率、受火时间、消防冷却水等因素对物证的抗拉强度、伸长率等特征参数的影响规律;分析化工储罐火灾中典型物证在复杂环境下的形成机理。(4)面向起火点认定的化工储罐火灾数值模拟。选用PDF非预混燃烧模拟方法和带浮力修正的CFD湍流模型对化工储罐火灾特性进行模拟分析,对火场温度、辐射分布规律进行数值研究。通过与实验结果的对比,检验该方法在储罐池火灾数值模拟方面的合理性。运用数值模拟方法,对化工储罐可能发生的三种典型火灾模式进行模拟,分析储罐内外壁各部位受火后强度和时间分布规律,为起火点认定提供物证基础。(5)基于物证的化工储罐火灾起火点推断技术。从理论上分析起火点特征与火灾现场物证特点之间的关系,建立化工储罐火灾事故起火点推断的系统方法,构建起火点推断的一般判据;结合数值模拟与模拟实验方法,建立基于金属物证力学性能变化的受火温度、热辐射强度和受火时间的推断判据,为起火点确定提供判定依据。更多还原

【Abstract】 Factors influencing the chemical storage tank fire are numerous, the hazards, complexity of accident mechanism, serious damage to the fire scene. These factors often bring tremendous difficulties to fire scene investigation and affirmation of origin of fire. On the present condition of weak evidence of fire investigation, low persuasion, and urgent lack of analytical techniques of physical evidence,doing research on material evidence inferring techlogy, setting up a set of system for the investigation and physical evidence analysing technology of fire accidents containing scientific researching & evidence obtaining methods, systematic reasoning methods, numerical simulation techniques, will be very helpful to analysis the origin of fire and reasons for fire accidents accurately and fast, the disadvantages of previous experimental analysing methods can be overcome and the scientificity and reliability of the investigation of fire accidents can be greatly improved.With the chemical storage tanks being specific object of study, using the strategy of typical case study, theoretical analysis, experimental tests and the combination of simulation, this thesis is aiming at analysing characteristics and failure mechanism, studying the combustion behavior and forming mechanism of typical physical evidence, and numerical simulation of the chemical storage tanks fire on fire’s origin confirmed and deducing technologies and methods of the fire origin, and set up deducing criteria of fire origin of the chemical storage tanks fire. The main research contents are as follows:(1). Characteristics & Failure Mechanism of Chemical Storage Tanks fireIn the basis of summerizing the characteristics of chemical storage tanks fire, statistic analysis on 50 typical fire accidents of chemical storage tanks in late 30 years is made. From the point of view of accident investigation, the communal rules and traits are found, the typical types of fire accidents are summarized, the principal forms the damage fire accidents of chemial storage tanks do to external objects are analysed. The theoretical model of tank temperature rise in two heat transferring forms and different failure mechanisms the objects suffered in both internal and external fire during fire accidents are studied.(2). Simulated Experiment of Chemical Storage Tanks fire CharacteristicsSet up experimental platform for diesel storage tanks in minisize. Measure temperature, radiation, height, shape and other features of the storage tanks fire by two ways: contact & non-contact. Analyse developing process and boiling phenomenon of the fire. Build the relationship of height- temperature, lasting time- flame temperature and flame temperature- thermal radiation, and get the distribution of temperature field & radiation field chemical storage tanks fire have in different burning periods. Study the influence height of liquid level, aquifer, thickness of oil layer, oil’s initiative temperature, fire fighting & water jetting and other factors have on the flame temperature. Analyse features and rules of disaster in the process of fire accidents of storage tanks.(3).Typical Physical Evidence of Chemical Storage Tanks Fire and its Forming MechanismSet up physical evidence system of chemical storage tanks fire. Experimentally study the relationship between time & temperature under the influence of fire and the mechanics property of typical physical evidence, like Q345R, Q245R, 235R, etc, under the environment of simulated fire. Study rules of temperature rise rate, fire duration, water jetting have on the strength of extension, elongation and other feature parameters of metal physical evidence. Analyse the forming mechanism of metal physical evidence of fire accidents under complicated circumstances.(4). Numerical Simulation of Chemical Storage Tanks Fire Based On the Origin of FireConduct simulation analysis of features of chemical storage tanks by electing analogy methods of PDF non- premixed combustion and CFD turbulence models with buoyancy correction and numerical research of fire temperature & distribution rules of radiation. Check its rationality in the respect of numerical simulation of pools fire of storage tanks, by the contrast with experimental result. Do a simulation of three modes of fire accidents of chemical storage tanks using numerical simulation. Analyse the intensity and time distribution rules of inside & outside of storage tanks after a fire, offering physical evidence for the affirmation of fire’s origin.(5). Deduction Technology of Chemical Storage Tanks Fire Origin Based on Physical EvidenceTheoretically analyse the relationship between characteristics of fire’s origin & physical evidence of fire scene, set up systematic methods for chemical storage tanks fire origin and form ordinary criteria for deduction of fire’s origin. Set up deducing criteria of fire exposure temperature, fire duration and fire spreading direction based on changes of mechanical property of metal physical evidence, together with numerical simulation and simulation experiments. Analyse evaluation methods of corresponding fire parameter, offering judgement basis for the confirmation of fire’s origin.更多还原