【作者】 尹奇志；

【导师】 肖金生； 杨波；

【作者基本信息】 武汉理工大学 ， 轮机工程， 2002， 硕士

【摘要】 随着石油工业的迅速发展，液化气在工业与民用领域得到了日益广泛的应用。但液化气是易燃易爆的物品，随着起用量不断增加，它在运输和贮存过程中发生的爆炸事故，对人类正常的生产和生活造成了严重威胁。为此，人们高度重视并积极开展了液化气事故的相关研究工作。其中，计算液化气容器在高温环境下的瞬态应力分布，预测含有裂纹的液化气压力容器在高温环境下是否进一步扩展，以及在此基础上开展液化气爆炸机理的研究，对于确保液化气的安全运输和贮存有着直接的指导作用。 本文针对高温环境下液化气压力容器的热响应特性问题，结合交通部重点科技项目“液化气体类危险品运输安全预警系统的研究”和湖北省自然科学基金项目“液化气容器爆炸机理研究及数值模拟”，对在火焰包围下的液化气压力容器的温度场分布、强度计算、裂纹扩展预测以及爆炸事故机理等方面开展了多学科的交叉研究。文章主要从三个方面进行了探讨。 首先，工件安全与否与其所受应力大小和其温度高低有很大关系，这对液化气压力容器也是适用的。为便于对液化气压力容器的安全状况进行判断，本文对液化气压力容器的瞬态温度场分布以及其瞬态应力分布分别进行了计算。在液化气容器的温度场分布计算中，本文首先建立了火焰包围下液化气容器的传热模型，然后根据传热学理论确定了液化气容器瞬态传热的边界条件，并结合PLGS99软件计算出了填充量为41％的球形液化气压力容器模型的换热边界条件，最后应用ANSYS计算了该模型的瞬态温度场分布，并进行了分析。在液化气容器的应力计算中，液化气加压容器的应力主要是由热应力和机械应力共同作用引起的。为了弄清这两种应力分别对总压力的影响的大小，首先单独对液化气压力容器仅受温度载荷时的瞬态当量热应力以及仅受内壁压力时的瞬态当量机械应力进行了计算分析，然后计算了液化气容器的当量总应力并对其进行了分析比较。 其次，液化气容器的失效过程通常分为裂纹形成和裂纹扩展两个阶段，本文在对无裂纹液化气容器的瞬态温度场和应力场进行了计算后，对含有初始表面裂纹的液化气容器的瞬态应力强度因子进行了计算和分析。 武汉理工大学硕士学位论文 — — 论文最后分析了高温环境下液化气容器爆炸的事故机理，即高温环境下液化气容器爆炸的主要诱因为：1）阀门打开时的压力骤降；2）容器壁温度过高，导致容器壁的材料强度降低；3）容器壁的温度不均匀引起的热应力。在常见的预防保护措施之中，喷淋装置、热绝缘层保护简单易行，保护效果好。另外，对减压阀的改进也有利于防止液化气贮罐爆炸。更多还原

【Abstract】 Wth the fast development of petroleum industry liquefied petroleuxn gas (LPG)is used increasingly in industrial and civil area. Because LPG is combustible andeXPlosive material, with increasing of its consUInPtion, accidents of LPG occursomctimes in tranSPortation and storage. Accordingly, accidellts of LPG are anachedgreat imPortance, and relevam research is developed. Ainong these researches,transient stress distriblltion calculation, predication of crack propagation and stUdy onthe failure mechhasm of LPG vessel under high temPeratUre has a great significancefor insuring safe transportation and storage of LPG.This paPer aims at the characteristics of thermal response of LPG vesse1 underhigh temPeratue, conjoining the prOject of "Study On TransPortation SafetyEarly-wdring System of LPG Dangerous Goods" suPported by TransportationDepartInen of China and the prOject of "Mechanism StUdy and Numerical Simulationof the ExPlosion of LPG Vessel" suPported by Science Foundation of Hubei Province.The interdisciplinary research has been done among temPerature field distribution ofLPG vessel under flame surroundings, intensity calculation, crack propagationpredication and mechanism of explosive accident, etc. Three parts are analyzed anddiscussed.First, the safety of a workPiece is related to stfCss it bears and its temPeta, sois LPG vessel. TemPeratUr field distribution and stress field distriblltion of LPGvessel are calcu1ated in order to eStimate its safety statlls. As to the calculation of thetemPedee fie1d distribulion. the heat transfer model of LPG vessel under flamesurroundings is set uP firSt, then the heat transfer boundary conditions of LPG vesselare determined according to the heat transfer theory and the heat exchange boundaryconditions of LPG vessel of global shaPe with 4l percellt fill rate is calculated interms of PLGS99 software, finaly the temPerafore field distribution of this model iscalculated and analyzed by ANSYS software. Wth regard to stfess calculation ofLPG vessel, the stress of LPG vessel is caused mainly by thermal stress andmechanical Stress. In order to make clear the influence of two kinds of stress to thetotal Stress, equivalellt thermal stress of LPG vessel under only temPertae load andits equlvalent mechanical stress under only inner wall stress are calculated andanalyZed, then its equivalent total stress is calculated, analyzed and comPared.’ Second,Jhe failure process of LPG vessel usually includes two phasest the crackformation and the crack propagation. After the temPeratat field distribution and theIIl.stress field distribution of LPG vessel without cracks are calculated, the stress intensity factor of LPG vessel with initial radial crack as well as surface crack are calculated and analyzed.In the end, the mechanism of explosive accidents of LPG vessel under high temperature is analyzed. The major inducements of LPG vessel under high temperature are as follows: 1) sudden falling of pressure on valve opening; 2) material strength falling of vessel wall, which is caused by high temperature of vessel wall; 3) thermal stress that is caused by non-uniform temperature of vessel wall. Among usual measures of precaution and protection, spray system and thermal insulated layer are easy and effective. In addition, the improvement of the relief valve is propitious to prevent the explosion of LPG vessel.更多还原