应用光纤布喇格光栅传感器监测地下管道腐蚀的新方法研究

地下管线工作环境恶劣,腐蚀是引起它破坏和失效的主要原因之一.本文提出了一种应用光纤光栅传感器监测管道腐蚀的新方法.输送石油和天然气等一些物质的管道内部存在的压力会使管道发生膨胀,进而导致管道外壁产生环向变形.假定管道为无限长,管道内部压力导致的管道外壁轴向应变可忽略不计,当管线发生腐蚀时,会导致管壁变薄,管道内部的压力又可以看作基本不变,这样就会增大管道外壁的环向应变.当管道内部压力保持恒定时,管道壁厚与应变之间存在一定的反比例关系,本文方法就是将封装好的光纤光栅传感器粘贴在管道外壁,通过监测外壁环向变形来判断管道腐蚀的情况和程度.通过理论值、模拟值和试验值三者的对比分析来说明了这种新方法是可行的,并且值得被广泛应用,为埋地管道的防灾减灾提供了一种对策.

A New Method for Underground Pipeline Corrosion Monitoring Applied FBG

In atrocious working conditions, corrosion is one of the major failure modes for underground pipelines. A method for monitoring pipeline corrosion applied fiber Bragg grating(FBG) sensor is proposed. Internal high pressure of pipes caused by carrying oil, gas and other matters will expand the pipe and then result in hoop strain on pipe outer wall. Assuming the pipeline has an indefinitely length, the axial strain pipe outer wall caused by internal pipe pressure is negligible. The pipe wall will be thinning at corrosion, while the pressure inside the pipe remains about the same, and this will increase hoop strain of the outer wall. Pipe wall and the strain are to some extent in inverse proportion when internal pressure keeps constant. This method attached packaged fiber grating strain sensors to the surface of pipe, the corrosion extent of pipe can be judged by monitor hoop strain. Through detailed contrastive analysis of theoretical value, analogue value and test value to explain the method is practical and worth being extensively applied and spread, and then provide strategy of disaster prevention and reduction for underground pipeline.