Research On Technology Of Material Evidence Of Deducing Fire Origin For Chemical Tank Fire

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.