Optimized design and simulation of high temperature pressure pipeline strain monitoring with optical fiber sensing technology

摘要

High temperature pressure piping have been applied widely in the chemical industry, the petroleum enterprises and the electrical power plants, and corresponding accidents happened frequently every year owing to the pipeline leakage and explosion. By massive accident statistics and analysis, the high temperature creep and the pipeline inside wall corroding are the main causes to result in the pipeline leakage and explosion accident. By real time sensing the strain change of pipeline outer surface, the online working status of the high temperature pipeline could be monitored and the leakage and explosion accidents would be avoided. Now several methods can be considered to sensing and monitoring the strain change of the high temperature pipeline surface, including Electricity sensor examination method, ultrasonic wave examination method and infrared thermal imagery examination method. After careful analysis and contrast, Electricity sensor examination method was given up for it couldn't be working steadily under high temperature conditions and easily excitat^d electric sparks which would result in flammable explosive danger in chemical industry and petroleum enterprises. Ultrasonic wave examination method and infrared thermal imagery examination method could avoid the shortages of Electricity sensor examination method based on the non-destructive examination theory, but the ultrasonic wave method could be applied only in examining the pipeline wall thickness, the inside wall crack as well as the material air bubble flaws restricted in its working principle. Consequently ultrasonic wave method examination method wasn't suitable to sense and monitor the strain change of the high temperature pipeline surface; Infrared thermal imagery examination method has low sensing resolution and can only examine internal etching pit and wall thickness attenuating, so it is unable to examine the pipeline surface strain change on time. Therefore three reported real-time examination methods mentioned above cannot satisfy the strain change monitoring of high temperature pressure piping. In this paper a novel method is presented using optical Fiber Bragg Grating sensor to carry on the real-time monitoring of the high temperature pressure piping surface strain change, firstly the stress and strain analysis of the high temperature pressure piping surface is given based on the established theoretical model, then optimized design and simulation is accomplished with computer ANSYS software. In the end a optimized set-up is put forward and discussed.