基于干涉型分布式光纤技术的水下管道泄漏检测实验分析

为解决复杂水下管道的泄漏检测问题,以干涉光路为基础,构架面向水下管道应用的分布式光纤泄漏检测系统.在水下波导实验室,以直径为200 mm的铸铁沥青输气管道为对象,研究水流波动条件(流速为2～6 m/s)、气压0.5～1.4 MPa下,分析Sagnac原理中零点频率和泄漏点在宽频范围内的对应关系,建立零点频率分辨率和定位的关系,消除水下环境干扰信号的影响.实验结果表明:该系统可用于水下输气管道泄漏检测,对于6.5 km测试间距,可有效测定泄漏源位置,定位误差小于2.0％.

Underwater gas pipeline leakage and location simulation in lab-scale based on optical fiber interferometer

For underwater gas pipeline leaky detection,a distributed optical fiber sensor system was bulit based on the principle of hybrid interferometer.In underwater waveguide lab,the simulated underwater pipeline testing system was constructed.Under 2?6 m/s current velocity and 0.5?1.4 MPa pressure,simulated offshore pipeline leakage detection and location test was performed based on Sagnac interferometer principle.The relationship between null frequency position and leakage point was analyzed in broad frequency band.Different flow velocities and gas pressure experiments were performed.The underwater environment noise distribution was analyzed.The results show that underwater leakage location precision meets the requirements,and the relative error is less than 2.0% for 6.5 km simulated detection spacing.