Research On Pipeline Leakage Monitoring Based On Fiber Bragg Grating Sensor

Although the total mileage of oil pipelines throughout the country is increasing continuously,some pipelines may cause leakage accidents due to illegal construction,geological natural disasters and long-term corrosion damage,and so on.It causes huge economic losses and serious pollution to the society.Therefore,it is necessary and meaningful to strengthen the monitoring and management of pipeline,to find out the leakage of pipeline and to take rescue measures quickly so as to avoid causing greater harm and property loss.Based on the characteristics of fiber grating sensors that can be arranged into networks and real-time on-line monitoring,the leakage behavior of pipelines is monitored and studied in this paper.Because of the sudden and transient characteristics of pipeline leakage,the fluid in the pipe will produce negative pressure wave,and the circumferential strain of the pipeline will be changed.Based on the circumferential strain principle of pipeline and the sensitive characteristics of fiber grating strain sensor,the circumferential strain of pipeline caused by leakage is monitored and studied.The experimental scheme is designed to study the variation law of pipeline leakage,and a set of experimental device which can monitor the circumferential strain of pipeline is designed independently,and the monitoring performance of the experimental device is tested and analyzed.It is found that the designed experimental device can accurately monitor the variation of pipeline strain with the increase of pipe pressure and the decrease of pipeline strain with the increase of pipeline wall thickness.The transient strain changes of the pipeline under the valve opening and closing conditions and the external load impact can also be monitored.The experimental results show that the experimental device can judge the pipeline leakage accident by capturing the leakage signal caused by the negativepressure wave caused by the pipeline leakage and changing the circumferential strain of the pipeline.The influence of pipe pressure,pipeline wall thickness and leakage velocity on the leakage signal of monitoring pipeline circumferential strain is studied by means of the experimental device,and the rule of influence is summarized.