针对传统漏磁检测(magnetic flux leakage,MFL)技术难以满足钢制油气管道裂纹检测需求,提出一种剩磁检测(residual magnetic flux leakage,RMFL)技术,直接利用漏磁检测后管壁的剩磁状态实现小开口裂纹的有效检测.相较于漏磁信号,剩磁信号信噪比较低,对传感器的采样频率有更高的要求,因此提出一种空间分辨率方法优化剩磁信号采样频率.首先通过有限元仿真建立管道动态磁化模型,提取裂纹特征数据,并分析其分布规律.其次采用频域分析方法,优化剩磁信号采样频率.最终通过实验验证了基于空间分辨率的裂纹剩磁检测方法的有效性.结果表明,基于空间分辨率的剩磁信号与原始信号高度吻合,在信号波形的极点处均有不失真采样点,保存了原始信号的关键特征,为裂纹尺寸的量化提供了重要的数据基础.该技术可实现管道小开口裂纹的有效检测,工程实用的可操作性强,有助于油气管道裂纹内检测技术的进一步发展.
Residual Magnetic Signal Detection Method of Steel Pipeline Crack Based on Spatial Resolution
The traditional magnetic flux leakage(MFL)detection technology is difficult to meet the requirements of steel oil and gas pipeline crack detection,a new residual magnetic flux leakage(RMFL)detection technology was proposed,which directly used the residual magnetic state of the pipe wall after MFL detection to realize the effective detection of small opening cracks.Compared with magnetic leakage signal,remanent signal had lower signal-to-noise ratio and higher requirement on sampling frequency of sensor.Therefore,a spatial resolution method was proposed to optimize sampling frequency of remanent signal.Firstly,the dynamic magnetization model of pipeline was established by finite element simulation,the crack characteristic data was extracted,and the distribution law was analyzed.Secondly,the frequency domain analysis method was used to optimize the sampling frequency of residual magnetic signal.Finally,the effectiveness of the crack remanence detection method based on spatial resolution was verified by experiments.The results show that the remanent signal based on spatial resolution is highly consistent with the original signal,and there are undistorted sampling points at the poles of the signal waveform,which preserves the key features of the original signal and provides an important data basis for quantifying the crack size.This technology can realize the effective detection of cracks in small openings of pipelines,and has strong engineering practicality and operability,which is conducive to the further development of crack detection technology in oil and gas pipelines.
oil and gas pipelinesremanence effectcrack detectionspatial resolution
万方数据
维普
