Design and application of distributed Raman thermometry system based on multi-modal Gaussian fitting

Aiming at the problem that the length of the temperature sensing area is smaller than the spatial resolution, which leads to inaccurate temperature measurement, a multi-point temperature correction scheme was proposed, and a device and method that could be applied to the measurement of temperature distribution in medium and small scale sections were introduced. Using the scheme based on multi-modal Gaussian fitting, the simultaneous correction of multiple inaccurate temperature points was realized, and the temperature accuracy of the system was improved. A prototype of the distributed Raman thermometry system was designed, and the measurement of temperature distribution in medium and small scale sections was realized by wrapping the fiber around the PPR tube. The experimental device improved the measurement accuracy of 2 m and 1.5 m temperature sensing areas to 1 °C, the thickness of the ice sheet of the Wanjiazhai Reservoir on the Yellow River in winter was measured to be 42.33 cm, which was 1.67 cm different from the artificial measurement results, and the measured temperature of 36 m deep river water profile fluctuated in the range of 0.32 ℃ ~ 0.90 ℃. The experimental results show that the distributed Raman thermometry system can monitor the temperature distribution of the river flow profile on a large scale in the field.