【作者】 邢志祥；

【导师】 蒋军成；

【作者基本信息】 南京工业大学 ， 化工过程机械， 2004， 博士

【摘要】 液化气储罐火灾爆炸事故是液化气生产、储存、运输过程中常见的事故类型,事故一旦发生将对人民生命和国家财产造成重大损失。储罐爆炸的重要原因之一是受到火灾的作用造成储罐压力升高。对液化气储罐在火灾作用下的热响应行为的研究,可以为液化气储罐事故预防和控制提供重要的理论依据。为此本文从以下几个方面进行了研究。 作为研究工作的基础,本文进行了液化石油气和油品基础物性数据的计算研究。针对液化石油气和油品多组份的特点,给出了单组份热力学参数和传递参数的计算关系式,并根据混合规则给出了混合物的计算关系式。对于液化石油气体,分别按液体和气体计算其相关参数。此外,对液化石油气在高压下的过热极限的计算方法进行了研究,利用液体的RK立方型状态方程,通过求极值点的方法,计算其在高压力下的过热极限。 对液化石油气储罐进行了火灾和爆炸实验研究。设计并建立了液化石油气储罐火灾和爆炸研究的实验装置。并用实验装置进行了一系列的火灾和爆炸实验,实验结果表明,在火灾作用下储罐内液化石油气温度有明显的分层现象,分层加快了储罐内的压力升高速度,具有明显的增压效应。储罐的热响应受到火灾类型、储罐型式、充装水平等多因素的综合影响。储罐内的液相在火灾作用下可以处于过冷或过热状态。储罐压力随时间的响应关系可以用三次多项式拟合。 对液化气储罐的火灾环境的数值模拟研究。采用非预混燃烧的数学模型,并采用概率密度函数方法对燃烧的产物组份和温度场进行模拟,采用离散传播辐射(DTRM)模型和k-ε紊流模型对流场和辐射进行模拟。分别对无风和有风条件下的池火灾以及喷射火焰作用于卧式储罐、立式储罐和球罐时的流场和温度场进行了模拟,并对储罐表面的热辐射和总热流密度进行了模拟和计算。 建立了液化气储罐热响应的物理和数学模型。研究中,液化气体储罐热响应的物理模型的建立没有采用近似性假设和简化,因而模型更精确。液化气体液相和气相热响应数学模型的建立,模型考虑了液相中气泡的产生和运动对液相和气相热响应的影响。 对液化石油气储罐在火灾作用下的热响应的进行了数值模拟研究。将模拟结更多还原

【Abstract】 The explosion of pressurized liquefied gas (PLG) tanks is a general accident in the production, storage and transportation of PLG. This type of accident used to lead to serious damage of property and loss of life. The fire exposure is one of important reasons of accident which will be caused by the increasing of pressure in the tank, so it is essential to study the thermal response of PLG tanks exposed to fire, which can provide theoretical instruction for prevention and control of PLG tank accident. In this thesis, the researches for this topic are conducted as followings.As a basis of the research, the research of fundamental property calculation for liquefied petroleum gas (LPG) and oil fuel involved in this research is firstly carried out. In view of the characteristic of multi-components for LPG and oil fuel, relations for calculation thermal and transport properties for single component and the mixed regulation for multi-components are recommended respectively. For LPG different ways are adopted to calculating properties of liquid and gas respectively. The calculation method for the liquid superheat limit of LPG in high pressure is studied by using RK state equation.The experimental research on thermal response of LPG tank exposed to fire is carried out. A experimental apparatus to simulate real accident of LPG tank is designed and manufactured. A series of experiments for different fill levels, different type of tanks subjected to different type of fires are performed with this apparatus. From the results of the experiments, the obvious stratification of temperature in the ladings of the tank is observed. And the pressure is increased due to the stratification. Thermal response of the LPG is affected by various factors such as fire type, tank type and fill level etc.. The liquid could be superheated or sub-cooled in fire exposure situation. The pressure can be fitted to time by cube polynomial equation.The numerical simulation for fire environment of PLG tank is studied. The model for diffusion combustion is used, and the product of combustion and temperature field are simulated by probability density function (PDF). Discretetransport radiation model (DTRM) and k-g turbulence model are used to simulate radiation and flow field respectively. The cases of horizontal tank, vertical tank and spherical tank exposed to pool fire under wind or windless conditions, jet fire are simulated respectively. The radiation and total surface heat flux to target tanks are calculated.The models of thermal response of PLG tanks subjected to fire are set up. A more accurate physical model is described without using hypotheses of former researchers. The model of thermal response for liquid phase and vapor phase are set up respectively, the bubble growing and rising in the liquid phase is considered.The numerical simulations of thermal response of LPG tank exposed to pool fire and jet fire are carried out. Comparison of the simulating results to the experiment ones shows good agreement. Influence of various conditions on the thermal response of tanks is simulated. The simulating results show that the pressure and temperature of the ladings , the temperature of tank wall can be fitted to time with polynomial. The constants are determined by initial conditions, fire types, tank types and fill levels etc.. Jet fire is more dangerous for PLG tanks than pool fire, and in this situation, the pressure and wall temperature increase more rapidly. The sizes of tanks, fill levels and tank types also affect the response of tanks. The smaller the tanks and the more the fill levels are, the more rapidly the pressure increase. The pressure in vertical tank increases more rapidly than that in horizontal tank.Failure analysis for exploded tanks in the experiment is carried out. From the analysis it can be showed that plastic deformation is obvious before the tank failure occurs, the failure manner is ductile fracture, the first rupture starts at the position of seriously thinned wall of the tanks. After the initial failure of tanks, the tank could fail in three manner, ie. rapid BLEVE, slow BLEVE and jet release. Criterion of tank failure is set up. When the strength of seriously thinned wall is less than the strength limit of tank material at high temperature, the tank failure occurs. The formula for predicting the bursting pressure of the tanks exposed to fire is suggested. The failure time is predicted by simulating results and failure criterion which shows better agreement with experiment results. The prevention and control countermeasures ofPLG tank accident are suggested, and the simulating method for safety design is put forward. The safe distance of LPG tank accident is calculated.更多还原