【作者】 崔巍；

【导师】 戴光；

【作者基本信息】 大庆石油学院 ， 化工过程机械， 2010， 硕士

【摘要】 石化、炼油工业中使用的换热管由于长期处于腐蚀介质和交变应力作用下,很容易产生腐蚀和磨蚀。铁磁性换热管应用广泛,其腐蚀是管壳式换热器最主要的失效形式,常因此造成巨大经济损失。因此,换热管的定期检验是保证生产装置安全运行的重要措施之一。换热管多为碳钢管,受铁磁性效应和换热管管束结构的限制,需采用内穿式检测方法。漏磁检测技术以其高效率、高可靠性等优点,目前主要应用于储罐底板扫查、油/气输送管道缺陷检测等方面,国内采用漏磁技术对换热管检测鲜有研究。本文以换热管缺陷漏磁场为研究对象,综合运用理论分析、有限元分析、试验研究的方法进行换热管漏磁检测分析。分析了换热管漏磁检测的基本原理,应用电磁场数值计算中的有限元方法来研究漏磁场,将有限元法应用于换热管漏磁检测三维模型的建立及缺陷漏磁场的仿真,分析各方面因素对缺陷漏磁场产生的影响。首先,研究了换热管漏磁检测磁化结构中磁芯几何参数变化时对漏磁场的影响。然后,分析了缺陷尺寸、被测管壁厚度等参数对漏磁场分布的影响规律。最后,设计了两种聚磁结构,有限元分析结果表明,聚磁结构的应用较大程度提高了漏磁检测的灵敏度。在理论分析和有限元分析的基础上,利用绘图软件对换热管漏磁检测系统进行建模和装配体设计。组建了换热管漏磁检测系统,针对Φ38×3mm这种规格的换热管进行了试验研究。结果表明,采用该检测系统可实现对换热管不同类型缺陷的检测。更多还原

【Abstract】 The heat-exchange tube frequently bring on the corrosion and abrasion due to corrosion medium and alternating stress among petrochemical and refining industry. Ferromagnetic heat-exchange tube is employed commonly in industries, corrosion in tube is the main failure reason of shell and tube heat exchangers and it usually cause large economic loss. Therefore, the periodic inspection of the heat-exchange tube is one of the important measures to ensure the safe operation of process units. The heat-exchange tube need inside testing method for the effect of its ferromagnetism material and structure restriction. Magnetic flux leakage(MFL) technology with its high efficiency, high reliability, etc., is currently mainly used in tank bottom scanning, oil/gas pipeline defect inspection etc., the domestic rare study and use of MFL technology to detect heat-exchange tube.This text with MFL field of the heat-exchange tube’s defect for research object, use academic analysis, finite element analysis, experiment research method to carry on the analysis for MFL testing of the heat-exchange tube. The principle of MFL testing of the heat-exchange tube was introduced, and the MFL field is studied with finite element method(FEM) of electromagnetic numerical computation. The FEM is applied to establish the 3D model of MFL testing and MFL field simulation, and analyze various factors on the impact of the MFL field of the defect. Research the change of the geometry parameters of magnetic core among the magnetic structure of MFL testing of the heat-exchange tube to MFL field. After that, the laws of distribution of the MFL field are achieved with FEM numerical simulation,which are influenced by many parameters, such as geometric size(depth and diameter) and thickness of testing tube, etc. Also design two magnetic concentrating structure, and use the magnetic concentrating structure can tremendous increase the sensitivity of MFL testing.Base on the academic analysis and FEM analysis, by using plot software, the experimental system of MFL testing of heat-exchange tube is established, carry on the experimental study to theΦ38×3mm tube, and the results show that using the experimental system can realize the detection of the different defect’s types of the heat-exchange tube.更多还原