Pipeline Flow Rate Real-Time Monitoring Based on Optical FBG Fiber Acceleration Sensor

Non-invasive flow sensors will not interfere with the flow characteristics in the pipeline, which is the main research direction of downhole permanent flow sensors at present. In the extremely harsh environment of high temperature, high pressure, corrosion, and so on, the optical fiber sensor has higher reliability than the traditional electric sensor. The standard deviation of pipeline vibration is directly proportional to the wall pressure fluctuation caused by flow turbulence. Therefore, based on the fiber grating sensing principle and sensor geometry optimization method, a high-sensitivity fiber optic accelerator sensor was designed in this paper to sense the wall pressure fluctuation for non-invasive pipeline flow measurement. An experimental platform was set up to carry out relevant experiments. The standard deviation of vibration and the experimental data of flow rate were fitted by exponential fitting and quadratic fitting methods, and the data indicate a fit of up to 98%. In the range of flow rate fitting error of ±5%, the exponential fitting method was better, and the lowest measured flow rate was 0.37 m/s. The experiment proves that the accelerator sensor can realize the non-invasive real-time measurement of underground pipeline wells.