抽油杆纵向裂纹漏磁检测研究

发布时间：2018-06-14 23:47

本文选题：抽油杆 + 纵向裂纹　；参考：《北京交通大学》2017年硕士论文

【摘要】：抽油杆作为采油作业中的重要部件,在其服役过程中,长期承受腐蚀介质的侵蚀以及不对称循环载荷的作用,极易形成横向或纵向的裂纹,甚至导致断杆事故。目前关于抽油杆纵向裂纹的检测装置结构复杂,制作成本较高。本文针对抽油杆纵向裂纹,进行了漏磁检测方法研究,在建模、提离值、实验装置等方面取得了成果。论文主要工作如下:1.研究了漏磁检测原理,利用ANSYS建立了径向磁化、单线圈轴向磁化和双线圈轴向磁化模型,通过对比抽油杆内部磁化的效果,确立了双线圈轴向磁化方案。根据电磁场相关理论和有限元分析思想,建立了抽油杆纵向裂纹漏磁检测的有限元模型,求解并分析了纵向裂纹处的漏磁场分布特征,得出了漏磁场随外加磁场强度、裂纹尺寸和提离值等的变化趋势。2.设计了抽油杆纵向裂纹漏磁检测的实验装置,包括双励磁线圈的绕制、检测元件的选定、信号调理电路和采集系统的设计。其中,双励磁线圈用于磁化抽油杆,检测元件用于拾取漏磁场信号,信号调理电路和采集系统用于实现检测信号的存取。3.对抽油杆的纵向裂纹进行了漏磁检测实验研究,并对采集到的缺陷信号进行了小波去噪,有效地保留了缺陷信号的突变特征。分析了提离值对缺陷漏磁信号的影响,提取了裂纹上方缺陷信号的极值,并根据数据拟合的方法,得到了传感器提离值与采集信号极值之间的函数关系。本文设计了一种磁化效果好、结构简单、成本较低的漏磁检测方案,从建模、仿真和实验三个方面进行了研究,实现了对抽油杆纵向裂纹的漏磁检测。
[Abstract]:Sucker rod, as an important part of oil production, is prone to form transverse or longitudinal cracks and even lead to failure of rod during its service, which is subjected to corrosion and asymmetric cyclic load for a long time. At present, the structure of the detecting device for longitudinal crack of sucker rod is complicated and the production cost is high. In this paper, the magnetic flux leakage detection method for the longitudinal crack of sucker rod is studied, and the results are obtained in the aspects of modeling, lifting the value, and the experimental device. The main work of this paper is as follows: 1. The principle of magnetic flux leakage detection is studied. The models of radial magnetization, single coil axial magnetization and double coil axial magnetization are established by using ANSYS. By comparing the effect of internal magnetization of sucker rod, the scheme of double coil axial magnetization is established. Based on the theory of electromagnetic field and the idea of finite element analysis, a finite element model for magnetic leakage detection of longitudinal crack in sucker rod is established. The distribution characteristics of magnetic leakage field at longitudinal crack are solved and analyzed, and the magnetic leakage field with external magnetic field intensity is obtained. The variation trend of crack size and lift value. An experimental device for magnetic flux leakage detection of longitudinal crack in sucker rod is designed, including the winding of double excitation coil, the selection of detecting elements, the design of signal conditioning circuit and the design of acquisition system. The double excitation coil is used to magnetize the sucker rod, the detection element is used to pick up the leakage magnetic field signal, the signal conditioning circuit and the acquisition system are used to realize the access of the detection signal. 3. The magnetic flux leakage (MFL) detection of the longitudinal crack in the sucker rod is studied experimentally, and the acquired defect signal is de-noised by wavelet transform, which effectively preserves the mutation characteristic of the defect signal. The influence of lift value on defect magnetic flux leakage signal is analyzed, and the extreme value of defect signal above crack is extracted. According to the method of data fitting, the function relationship between sensor lift value and acquisition signal extremum is obtained. In this paper, a magnetic flux leakage detection scheme with good magnetization effect, simple structure and low cost is designed. The magnetic flux leakage detection of longitudinal crack of sucker rod is realized from three aspects: modeling, simulation and experiment.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE933.2

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