管道缺陷有限元仿真技术量化方法改进研究

【作者】 刘警君；

【导师】 钮英建；

【作者基本信息】 首都经济贸易大学 ， 安全技术及工程， 2010， 硕士

【摘要】 管道系统广泛应用于冶金、石油、化工以及城市水暖供应等工业部门中,工业管道的工作条件非常恶劣,容易发生腐蚀,疲劳破坏或由管道内部的潜在缺陷发展成破损而引起泄漏事故。尤其是铁磁性油气输送管道由于长时间的腐蚀、磨损或意外的机械损伤等原因会形成各种缺陷.如未能在第一时间发现并及时做出修理,将最终导致管道内介质的泄漏,从而引发各类管道安全事故。为全面了解管线的腐蚀、破损状况,尽可能及时的对危险缺陷点进行处理,防止管道泄漏事故的发生,或是最大限度的减少事故造成的损失,必须利用管道检测装置对管道进行定期检测,以便及时发现管道缺陷.并且获得其位置、类型、几何尺寸等精确信息,从而为管道的安全评价、寿命预测、检修维护等提供可靠依据。因此,无损检测技术的应用和发展在对管道进行监测和诊断方面就显得尤其重要。管道内缺陷检测是在役油气管道缺陷无损检测的重要手段之一,在保障管道的安全、高效运行方面发挥着不可替代的作用。管道内缺陷检测分为漏磁缺陷无损检测和超声波缺陷无损检测,在我国,应用比较广泛的是漏磁缺陷检测。对在役含缺陷燃气管道漏磁检测技术进行研究,从而获得相对精确的管道缺陷特征参数,为定量评价管道缺陷的剩余强度提供可靠的缺陷数据。本文以磁通量泄漏(Magnetic Flux Leakage,简称MFL,即漏磁)原理为基础,以通过求解麦克斯韦方程的数值计算将有限元方法应用于建立缺陷漏磁场模型为核心,主要从以下方面进行论述和研究：(1)简单阐述国内外管道事业的发展及现状,作为运输载体其具有不可比拟的优越性；(2)介绍管道事故的常见类型——泄漏,辨识燃气管道安全运行存在的危险有害因素；(3)分析城市埋地燃气管网铺设的特点,试图揭示管道事故发生的规律,引出管道泄漏检测的必要性；(4)综述管道缺陷无损检测的方法,并仔细分析比对管道内缺陷漏磁检测和超声波检测,简单介绍国内外漏磁检测技术的发展；(5)介绍燃气管道漏磁检测系统的发展及在线监测装置的机械结构、工作原理和组成系统的特点；(6)阐述电磁场基本理论及铁磁性材料缺陷漏磁产生的机理,翔实论述MFL检测原理；(7)探讨缺陷漏磁场分析方法,并比较偶极子模型方法和有限元模型方法的优缺,通过求解麦克斯韦方程,建立缺陷漏磁场有限元模型；(8)概述有限元仿真基本理论及解题步骤,通过信号反演得出缺陷特征参数与漏磁场的关系,分析模型仿真产生的信号误差并探究修正方法；(9)简单介绍有限元仿真软件——ANSYS,并建立管道缺陷漏磁检测模型,并借助计算机模拟,运用有限元仿真技术对检测数据进行处理,得到缺陷漏磁场云图；(10)分别就缺陷的不同长度、宽度及深度进行有限元仿真,得到相应的漏磁场云图及轴向和径向分量波形图,研究缺陷的几何参数与漏磁信号的对应关系及变化规律；(11)说明此检测方法的不足之处和改进展望,并探寻进一步研究的方向,提出管道缺陷分级评价思想。更多还原

【Abstract】 Pipeline system is widely used in metallurgy, petroleum,chemical industry and urban plumbing supply industrial sectors. Because of industrial pipes working conditions are bad, prone to corrosion, fatigue damage or to defects in the development pipeline of potential internal damage caused by leakage.In particular, ferromagnetic oil and gas pipelines due to a long period of corrosion,wear and tear or accidental mechanical damage and other reasons will form a variety of defects[12]. Failure to discover and to make repairs, will eventually lead to pipe media leak, causing all kinds of pipeline accidents. A comprehensive understanding of pipeline corrosion, damaged condition,as much as possible against the risk of vulnerabilities in a timely manner for processing, to prevent a pipeline spill incidents, or to minimize losses caused by the accident. We must take advantage of pipeline inspection device on a regular basis pipeline inspection. The timely detection of pipeline defects and to obtain its location, type, geometry and so on accurate information, so as to pipeline safety evaluation, life prediction, and so provide a reliable basis for repair and maintenance[7]. Therefore, pipeline monitoring and diagnosis of non-des(?)uctive testing technology has become an important aspect.Inner surface pipeline detection is an important means of flaw detection, and to ensure the safe operation of pipelines play an important role. Magnetic flux leakage pipe inspection is divided inner surface flaw detection and surface flaw detection, in which magnetic flux leakage flaw detection applications is especially widespread in China. Flaws in the service with Gas Pipeline Magnetic Flux Leakage detection technology research, to gain a relatively accurate pipeline flaws characteristic parameters for the quantitative evaluation of pipeline flaws of the residual strength of the defect to provide reliable data. In this paper, magnetic; flux leakage (Magnetic Flux Leakage, referred to as MFL, the magnetic flux leakage) principle as the basis, by solving Maxwell’s equations numerical finite element method is applied to establish defect leakage magnetic field model as the core, mainly from the following aspects of exposition and research.a. Briefly discusses the development of domestic and international pipeline and the status quo, as a transport carrier of its incomparable superiority. b. Introducing the common types of pipeline accidents-spills, identify the safe operation of gas pipelines and present danger of harmful factors.c. Analysis of urban buried gas pipeline laying the characteristics of an attempt to reveal the laws of pipeline accidents, leads to the need for pipeline leak detection.d. Summary of Pipeline non-destructive testing methods, and a careful analysis of the pipeline than the magnetic flux leakage flaw detection and ultrasonic testing, magnetic flux leakage testing at home and abroad brief technology development.e. Introduced the Gas Pipeline Magnetic Flux Leakage Detection System development and on-line monitoring devices, mechanical structure, working principle and the characteristics of the composition of the system.f. Sets out the basic theory of electromagnetic fields and the iron magnetic material produced by magnetic flux leakage defect mechanism, detailed discussion MFL detection principle.g. Leakage magnetic field analysis method to explore and compare the dipole model approach and the finite element model approach the advantages and disadvantages, by solving the Maxwell equation,finite element model of the magnetic field leakage defects.h. An overview of the basic theory of finite element simulation and problem-solving steps, obtained by inversion of the signal parameters and magnetic flux leakage defect feature the relationship between the analytical model simulation of signals generated by the error correction method and explore.i. An outline of the finite element simulation software-ANSYS, and the establishment of Pipeline Magnetic Flux Leakage Inspection model, and rely on computer simulation, using finite element simulation of the test data processed by magnetic flux leakage defect cloud.j. Respectively on the defects of different length, width and depth of the finite element simulation, the corresponding leakage magnetic cloud and the axial and radial component waveform to study the defects of geometric parameters of the relationship between magnetic flux leakage signal and change the corresponding law.k. Illustrate the detection method deficiencies and improve the outlook, and to explore the direction for further research and put forward ideas pipeline defects grading.更多还原