Distributed Optical Fiber Temperature Sensing Technology And Its Application In Thermal Pipeline Leakage Monitoring

The heat pipe is a pipe that transports hot energy medium such as hot water or steam,and belongs to the modern city heating lifeline.With the development of the economy and the expansion of the city scale,the urban underground heat pipe network is also getting bigger and denser.Once the damage occurs,it will have a serious impact on heating and heat production,resulting in huge economic losses.The traditional pipeline leakage monitoring technology is susceptible to electromagnetic interference and not resistant to high temperature and high pressure.Due to the lack of distributed temperature monitoring technology and means,it is difficult to meet the intelligent monitoring requirements.The Distributed Optical Fiber Temperature Sensing System(DTS)technology has the advantages of passive,antielectromagnetic interference,corrosion resistance,high temperature resistance,light weight and low cost,gets rapid development.This paper deeply studies DTS engineering technology and several key issues in the thermal pipeline leakage monitoring system.Firstly,the paper explores the mechanism of optical fiber thermo-optic interaction,analyzes the principle and implementation of DTS technology based on Raman scattering,designs the demodulation algorithm of the system,and develops the DTS prototype,and the prototype developed has passed the 3C performance test organized by the Shenyang Fire Research Institute of the Emergency Management Department.Then,the paper puts forward the overall solution for system engineering application,researches the high temperature temperature-measuring fiber,formulates the communication protocol,develops the software of the upper computer,and studies the spiral winding optical cable laying method of the thermal pipeline.The ANSYS Workbench software is used to simulate and analyze the influence of environmental factors such as soil on the temperature measurement accuracy of the system.Finally,the paper establishes a health evaluation system based on DTS heat pipe.The health state evaluation model is established,and the weighted health evaluation method based on the analytic hierarchy process is studied.The heat pipeline health prediction algorithm based on BP neural network is preliminarily explored.The new DTS-based thermal pipeline leakage monitoring system studied in this paper can realize real-time collection,transmission,storage and calculation of pipeline temperature distributed data,and achieve the purpose of remote monitoring and leak location.The designed spiral-wound cable laying method helps to solve the blind spots of monitoring existing optical cable laying methods,and better realize real-time monitoring and leak point positioning.The results of this paper can provide a practical solution for the application of thermal pipeline leakage monitoring.