A Synchronous and Accurate Detection Method for Gas Pipeline Leakage Position and Flow Rate Based on Double Fiber Bragg Gratings

Fast and accurate detection of pipeline leaks plays an important role in reducing economic losses and ensuring the safety of personnel. However, for the two important indicators of gas pipeline detection, how to effectively detect the leakage location and leakage rate simultaneously is a serious challenge. In this article, we present an innovative optical fiber detection method based on double fiber Bragg gratings (FBGs) string to solve this problem. Combined with the theory of material mechanics and fluid mechanics, the binary equations are derived as the demodulation formula. In the detection, the corresponding physical quantities can be calculated by substituting the center wavelength of the two FBGs after drift. The experiments demonstrate that this sensor’s gas flow rate sensitivity in different positions can be up to 466.67 pm
$\cdot $
s/m. Meanwhile, at the same flow rate and different leakage positions, the sensor has sensitive symmetrical performance. The error results manifest that the velocity error is not more than 0.13 m/s, and the relative position detection error is not more than 0.167%. Overall, besides the extended measurement range and excellent linearity, our method also has the advantages of low production cost, simple structure, and ease of production, which is more suitable for gas pipeline health monitoring in the future.