输气管道清管过程管—土振动特征与卡堵定位方案研究

发布时间：2018-04-13 17:46

本文选题：清管器 + 管-土耦合作用　；参考：《西南石油大学》2017年硕士论文

【摘要】：输气管道清管作业可以对附着于管道内壁上的水、沉积物等杂质进行清理,能有效提高天然气集输系统的生产效率,保证天然气长输管道输送作业的顺利进行。但是目前所使用的人工监听跟踪清管器的方式存在较高的误判率,而电磁波法等实时检测技术与方法并不适用于所有的输气管道。如何根据清管过程中的管-土耦合振动特性实现清管器的准确定位成为了实际工程中亟需解决的问题。本文通过建立清管作业时的清管器作用下的管-土耦合模型,使用有限元软件对模型进行求解分析,明确了影响管道振动的因素以及振动在土壤中的传播规律,为采用光纤检测振动信号从而对清管器进行准确定位提供理论基础。本文的主要工作如下:(1)分析橡胶清管器、皮碗清管器等不同类型的清管器,并分别对各类清管器的结构、材料、适用范围等进行了研究,选择皮碗清管器这种清管作业当中使用广泛的清管器作为研究对象,研究清管作业过程中的管-土耦合动力响应特征;(2)根据清管器的运行特点以及埋地管道受迫振动的特点,利用达朗贝尔原理建立清管器运行状态下的四自由度振动方程,并采用Euler梁单元描述管道的响应特征。通过清管器皮碗与管道的位移关系,建立清管器作用下的管-土的耦合系统模型;(3)利用ABAQUS有限元软件的瞬态动力学求解器对耦合模型进行求解,分析清管器在不同的运行速度及管道内壁摩擦系数的条件下管道振幅的变化情况。计算结果表明在运行速度为0.8m/s时管道振幅达到27μm的峰值。并且管道振幅会随着清管器与管道摩擦系数的增加而增大;(4)在传播1000 mm的距离后竖直方向上的振幅的衰减率最小(66.1%),但在此距离上振动速度与加速度的衰减率基本相同。而在不同土壤弹性模量的计算结果中,在弹性模量为1OMPa的土壤中传播距离为200 mm时的振动速度明显高于其他土质中的振动速度,最大可达到70μm/s,在弹性模量为50 MPa的土壤中最大振动速度为27μm/s,说明土壤的弹性模量对振动速度有较大的影响;(5)对振动信号进行频谱分析,结果表明随着距离的增加振动信号的主要振动频率集中在5Hz附近,并以此为基础对信号进行16层小波软阈值降噪处理,得到清晰易于探测的振动信号,并根据计算结果及相关规范,建议在管道上方500mm的距离上敷设光纤检测效果较好。根据清管器作用下的管-土耦合系统的响应特点以及振动在土壤中传播规律,利用光纤对振动信号进行识别,提出包括频谱分析、小波降噪以及光纤敷设位置在内的清管器追踪定位的原理性方案。
[Abstract]:The pipeline cleaning operation can clean up the impurity such as water and sediment attached to the inner wall of the pipeline. It can effectively improve the production efficiency of the natural gas gathering and transportation system and ensure the smooth operation of the long distance natural gas pipeline transportation.However, there is a high rate of misjudgment in the manual monitoring and tracking pipe-cleaner, and the electromagnetic wave method and other real-time detection techniques and methods are not suitable for all gas pipelines.How to realize the accurate location of the pipe cleaner according to the coupled vibration characteristics of pipe and soil in the process of pipe-cleaning has become a problem that needs to be solved in practical engineering.In this paper, the coupling model of pipe-soil under the action of pipe-cleaner is established, and the finite element software is used to solve the model. The factors that affect the vibration of pipeline and the propagation law of vibration in soil are clarified.It provides a theoretical basis for the accurate location of the pipe-cleaner by using optical fiber to detect the vibration signal.The main work of this paper is as follows: (1) Analysis of different types of pipe cleaner, such as rubber pipe cleaner, leather bowl pipe cleaner, etc., and research on the structure, material and applicable scope of each kind of pipe cleaner, etc.In this paper, we choose the pipe cleaner as the research object, and study the characteristics of tube-soil coupling dynamic response in the process of pipe cleaning. (2) according to the operation characteristics of the pipe cleaner and the characteristics of forced vibration of buried pipeline,The four-degree-of-freedom vibration equation of the pipe cleaner is established by using the Darembert principle, and the response characteristics of the pipeline are described by Euler beam element.According to the displacement relation between pipe and pipe, the coupling system model of pipe and soil under the action of pipe cleaner is established. The transient dynamic solver of ABAQUS finite element software is used to solve the coupling model.The variation of pipe amplitude under different operating speed and friction coefficient of pipeline inner wall is analyzed.The calculated results show that the peak value of the pipeline amplitude is 27 渭 m when the running speed is 0.8m/s.Moreover, the amplitude of the pipeline will increase with the increase of friction coefficient between the pipe cleaner and the pipe. (4) the attenuation rate of the amplitude in the vertical direction after the propagation distance of 1000 mm is the smallest (66.1%), but the attenuation rate of the vibration velocity and the acceleration is basically the same at this distance.In different soil elastic modulus calculation results, the vibration velocity in the soil with 1OMPa propagation distance of 200mm is obviously higher than that in other soil.The maximum is 70 渭 m / s, and the maximum vibration velocity is 27 渭 m / s in soil with elastic modulus of 50 MPa, which indicates that the elastic modulus of soil has a great influence on the vibration velocity.The results show that the main vibration frequency of the vibration signal is concentrated near 5Hz with the increase of distance. Based on this, 16 layers wavelet soft threshold denoising is carried out to get the clear vibration signal which is easy to detect.According to the calculation results and relevant specifications, it is suggested that the fiber optic detection on the distance of 500mm above the pipeline is better.According to the response characteristics of the pipe-soil coupling system under the action of pipe-cleaner and the law of vibration propagation in soil, the vibration signal is identified by optical fiber, and the spectrum analysis is proposed.The principle scheme of tracking and positioning of pipe cleaner including wavelet denoising and fiber laying position is presented.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE973

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