Acoustic Field Imaging of Pipeline Turbulence for Noninvasive and Distributed Gas Flow Measurement

Precise control and measurement of the flow are essential for pipeline safety monitoring and economic accounting. Nowadays, the measurement of pipeline flow relies on point measurement schemes such as mechanical flowmeters, which invade the pipeline and can irreversibly damage the fluid pressure, especially when multipoint measurements are required. To overcome these problems, we have explored a novel technique in which the acoustic field properties of pipeline turbulence are reflected by distributed backscattering light field, from which the flow can be measured via acoustic field imaging. The acoustic field information is recorded by a helical deployment scheme using backscattering-enhanced optical fiber (BEOF) encapsulated in the polyethylene anticorrosive layer, thereby achieving highly sensitive, noninvasive, and distributed online monitoring of gas flows. We obtained 24-h flow fluctuation distributions with only one sensing fiber for two operating gas pipelines, and the flow measurement accuracy reached higher than 98% within the error range of −15% to 15%. Moreover, the minimum detectable flow is evaluated and it is demonstrated that the proposed scheme is extremely sensitive to weak flows. We successfully demonstrated noninvasive and distributed online measurement of operational pipeline flow, which will exhibit great potential for pipeline integrity management in the future.