The Research On Pipeline Health Monitoring Based On Distributed Optical Fiber Sensor

Pipeline transportation has become the lifeline of modern industry and the national economy. With the development of pipeline transportation industry, the safety problem of pipeline in service is increasingly serious for serious aging of the pipe network, coupled with the inevitable corrosion, wear and human damage and other factors.However, it is generally located in the bottom of the seabed and underground, monitoring and evaluation is not easy to implement. Therefore, it is of great practical significance to study the safety and feasibility of pipeline nondestructive health monitoring technology. In accordance with the requirements of the laying of the pipeline environment, combined with the advantages of strong anti electromagnetic interference ability, high temperature resistance, high temperature resistance, corrosion resistance, and long distance, distributed and accurate measurement in harsh environment, we focus on the research of pipeline health monitoring technology based on distributed optical fiber sensor in this paper, so that we can effectively monitor the health of submarine pipelines and underground pipelines.The main work of this paper includes the following aspects:(1)This paper introduced the background and current situation of pipeline transportation, and briefly introduced the current methods of health monitoring in the field of pipeline monitoring.(2)The basic theory of distributed optical fiber sensor and the basic principle of light scattering were introduced. Using Brillouin scattering can be used to accurately measure the strain, and the temperature can be measured in real time by using the Raman scattering. A method for monitoring the corrosion and leakage of the submarine pipeline and buried pipelines using the two physical quantities of strain and temperature was discussed.(3)The research of distributed monitoring method for the uniform corrosion of the inner wall of the submarine pipeline was carried out.The problem of monitoring the uniform corrosion of the inner wall of the pipeline was transformed into the monitoring of the circumferential strain of the pipeline by using Brillouin optical time domain technology to monitor.in this study, circumferential strain monitoring of the pipeline model was carried out by using the bare optical fiber with high precision as the sensing fiber.At the same time, the traditional resistance strain gauge was used to monitor the strain, and the corresponding numerical simulation was carried out.It showed that the three results were in good agreement, which meant that the distributed monitoring method was accurate and feasible.(4)The method of distributed monitoring of pipeline leakage was studied through the change of the temperature profile.The distributed optical fiber temperature measurement technology was used to monitor the leakage of the pipeline.It transformed the liquid leakage monitoring problem into the detection problem of the temperature of the surrounding medium.so as to realize the distributed detection of leakage of any position along the pipeline.The feasibility of the method was studied by the model test, and the implementation scheme and the applicable conditions of the method were obtained.(5)A simple numerical simulation of temperature field of pipeline leakage was carried out. According to the actual conditions of loading, we could see the leakage after the temperature field changes more intuitively. It also reflected the feasibility of monitoring temperature field,and provide a theoretical basis for distributed temperature monitoring method for pipeline leakage.Some qualitative and quantitative conclusions have been obtained in this paper, which is helpful to the monitoring and early detection of pipeline leakage and it have positive significance for the real-time monitoring and positioning of the pipeline leakage.