Fiber Mechanical & Thermal Multi-Parameter Sensing System Research For Low-speed Wind Tunnel

With the continuous development of science and technology,the application field of low-speed wind tunnel is more extensive and the requirement of mechanical and thermal parameter measurement is more stringent.Optical fiber sensing technology has the ability of anti-high low temperature,anti-corrosion,anti-electromagnetic interference and it is small,lightweight and accurate.And it can adapt to complex environments of wind tunnel environment.However,most of the optical fiber sensing instruments can only measure a single force or heat parameter.To monitor more physical parameters in wind tunnel,we have designed and developed the optical fiber thermal complex sensor system,combining optical fiber Fabry-Perot sensing technology with optical fiber grating sensing technology.Here are the main components of our study.1.This thesis introduces the research status and classification of optical fiber Fabry-Perot sensing technology,optical fiber grating sensing technology and the optical fiber mechanical and thermal parameter sensing in low-speed wind tunnel.Then we explain the significance of this system development.2.We have built the optical fiber mechanical and thermal complex sensor system for low-speed wind tunnel on the basis of engineering demand and studied following modules: holistic design and physical design.Starting with the demodulation method of low-coherence interferometry based on monochrome frequency absolute phase,the principle of two wavelength quadrature phase demodulation and the F-P filter demodulation method based on F-P etalon,the thesis also presents the design of optical fiber Fabry-Perot sensing subsystems and optical fiber grating sensing subsystems.3.We have designed the multi-sensor monitoring software for low-speed wind tunnel including layers of software logic,database access and human-computer interaction,which realize real-time display and data query of multi-Force thermal parameters.And the software has been verified to be well-performing through system tests.4.We have carried out a mechanical and thermal parameter measuring experiment to the airplane model in the low-speed wind tunnel,taking advantage of optical fiber multi-parameter sensing system.Meanwhile,we made a numerical simulation to the stress condition of the airplane.The result shows the data variation trend of the simulation equals to that of system measurement.And the span error is 0.38%F.S.,which provides a reliable monitoring data.