Design and preliminary experiment of optical fiber F-P pressure sensing system working in wind tunnel

In order to meet the requirement of atmospheric pressure measurement in the aviation field, based on the principle of the optical fiber Fabry-Perot (F-P) sensing and low coherence interference, an optical fiber F-P multi-channel pressure sensing system was proposed. First of all, the demodulation algorithm and basic principle were introduced, the calibration method and temperature compensation of the optical fiber F-P pressure sensor were analyzed in theory. The fitting error of the sensor under non-constant temperature condition was reduced to 0.134% F.S.. Then, in the wind tunnel environment within -4-4 sideslip angle range, the pressure measurement experiment was carried out on three monitoring points of the aircraft model. The results were compared with the simulation results using Ansys-Fluent software. In conclusion, the results show that the system using the optical fiber F-P pressure sensor and the Ansys-Fluent numerical simulation have the same trend of demodulation results, with the full range error of 0.38% F.S.. The experiments confirm that the system can provide reliable pressure data accurately and reflect the pressure of the aircraft model's monitoring points in the wind tunnel.