【作者】 孙文栋；

【导师】 方江敏；

【作者基本信息】 华南理工大学 ， 油气储运工程， 2010， 硕士

【摘要】 LPG具有易燃易爆的特性,在其生产、储存和使用过程中极易引起火灾、爆炸事故,尤其在液化石油气储罐区,一旦发生事故,可能造成大量的财产损失和人员伤亡,因此,对LPG储罐火灾爆炸故事危害性进行研究,建立相应的数学模型和物理模型,借助计算机仿真技术进行模拟,这将对预测、预防、控制事故的发生、保障生产的安全运行具有重要的理论价值和现实意义。论文的具体工作包括:(1)对LPG储罐区的火灾爆炸危险性进行分析。运用三类危险源理论对LPG储罐区进行危险源辨识,总结了LPG储罐区内三类危险源的形式、产生原因和相互作用关系。分析结果为,第一类危险源是液化石油气;第二类危险源是LPG泄漏后达到可燃浓度和存在点火源;第三类危险源是管理缺陷。分析了LPG储罐区常见的火灾爆炸事故后果模式。(2)对LPG池火灾热辐射进行数值模拟研究。分析了池火灾的燃烧特征、关系模型和热辐射破坏准则;在总结前人研究工作的基础上,对池火灾火焰形状进行理论分析,建立了物理模型和几何模型,提出合理假设,然后选择合适的辐射模型,确定初始和边界条件,应用Fluent软件模拟液池直径为12m时LPG池火灾热辐射对周围环境的影响,得出火焰周围入射热流密度分布图;模拟结果显示池火灾热辐射强度随着目标点到火焰中心距离的增加而迅速减小;结合热辐射破坏准则,可以确定池火灾的伤害范围,分别为死亡半径21m,二度烧伤半径35m,安全临界半径55m;分析液池大小、风速因素对热辐射的影响表明:火焰长度和各种伤害半径随着液池直径的增大近似线形增加;受风的影响一般下风向辐射热量增大,而上风向辐射热量减小,危害区域向下风向发生偏移。(3)对LPG爆炸性气体危险区域进行分析。LPG发生泄漏后与空气混合形成爆炸性气体,当遇到火源就可能发生爆炸事故。运用数值计算方法,基于Fluent软件对爆炸性气体扩散进行研究,得出在不同风速条件和初始条件下爆炸性气体的扩散规律;结合LPG爆炸极限,量化爆炸范围;运用Fluent软件中的图形显示功能,使危险区域的范围更加直观具体,从而为LPG储罐区安全评估和制定事故应急救援预案提供有价值的参考数据。本论文的研究是CFD方法用于易燃气体危害性研究的有效尝试,可以为罐区其它形式的灾害提供一种分析思路和方法。更多还原

【Abstract】 LPG has flammable and explosive characteristics. Fire and explosion can easily be caused in the process of LPG production,stockpiling and use. Especially in the LPG storage tank area, severe property damage and human casualties may be induced in case of an accident. Therefore,it is very necessary to study the hazardous consequences of fire and explosion of LPG tank. Setting up relevant physicals models and mathematical models and modeling by computer imitate technique which will predict, prevent and control accidents and ensure the production safety are of great theoretical value and practical significance. The detail research contents are as follows:(1)The fire and explosion hazards of LPG tank area were analyzed. According to the three types of hazards theory, hazards were identified in LPG storage tank area. The forms,causes and interaction of three types of hazards in the LPG tank area were summarized. The main dangerous substance was LPG which was the lst class hazard; LPG reaches to a flammable concentration was the 2nd class hazard; management bug was the 3rd class hazard. The common modes of fire and explosion consequences in LPG storage tank area were analyzed.(2)Numerical simulation for the thermal radiation of LPG pool fire was studied. Combustion characteristics, relational model and radiation damage criteria of pool fire were introduced. Based on the previous study, the flame shape of pool fire was theoretically analyzed; physical and geometrical models were established according to the reasonable assumption. Appropriate radiation models were selected and the initial and boundary conditions were determined; the thermal radiation to environment from the pool fire (D=12m)was numerically simulated using Fluent software and the contour of incident heat flux around the flame was obtained. Simulation results showed that the pool fire heat radiation decreased rapidly along with increase of the distance from the target point to the flame center. The damage range of pool fire was calculated combining with radiation damage criteria: death radius21m, second degree burn radius35m, critical safety radius55m. The thermal radiation affected by pool size and wind was analysed which showed that: flame length and radius of the injuries increased approximatel linearly as the pool diameter increases. Because of the influence of wind, the heat radiation of downwind direction increased while reducing against the wind direction, hazard areas moved to the downwind direction.(3)LPG hazardous areas of explosive gas were analyzed. After LPG diffusing into the atmosphere,mixing with air and forming explosive gas,it is likely to initiate explosion if meeting ignition sources. Explosive gas diffusion was studied using numerical simulation method based on Fluent software; the diffusion laws of explosive gas were simulated under different wind conditions and initial conditions; the scope of explosion was calculated combining with LPG explosion limit; the range of hazardous area was more intuitive and specific using the graphical display capability of Fluent software so as to provide valuable reference data for LPG tank area safety assessment and emergency plans.The study in the paper was a valid attempt to study the danger of flammable gas using CFD method,which offered a new thought way to study the other style disaster about storage tank.更多还原