Research On Magnetic Field Sensing Technology Based On Magnetic Fluid Materials

Optical fiber sensors are widely applied in the field of space environment monitoring because of their unique advantages,such as small size,anti electromagnetic interference,high sensitivity,corrosion resistance and easy to build distributed network.In aerospace,power system and other fields,the magnetic field in the environment has a great influence on the normal and stable operation of the instrument and equipment.The timely monitoring of the size of the magnetic field is of great practical value for ensuring the healthy and stable operation of the instruments and equipment and reducing the maintenance cost.Therefore,this paper proposes the study of magnetic field sensing technology based on magnetic fluid materials.The main work includes the following aspects:First,an end reflection measurement system based on Fresnel reflection principle is constructed to measure the refractive index of magnetic fluid materials.The permanent magnet and solenoid model is built by COMSOL multiphysics simulation software,and the magnetic field distribution characteristics of permanent magnet and solenoid under different parameters are obtained by numerical simulation.Secondly,the composite structure of LPG and FBG is studied.OptiGrating software is used to study the effect of grating period,length and modulation depth on transmission spectrum,and the magnetic field is monitored rapidly by amplitude modulation.Thirdly,the principle of optical fiber magnetic field sensing based on the principle of optical time domain reflection(OTDR)is studied.A long-range distributed optical fiber magnetic field monitoring method is proposed,which realizes the magnetic field sensing test of single probe and double probe.Then,the single-mode-multimode fiber structure is studied.The influence of multimode fiber length and core diameter on transmission energy is simulated by RSOFT software.The measurement of magnetic field is realized by constructing a reflective fiber sensing system.Then,the principle of OFDR fiber sensing based on Rayleigh scattering principle is studied in view of the monitoring requirements of the aircraft structure service state.On this basis,a distributed optical fiber sensing monitoring system based on OFDR is constructed to monitor various parameters,such as magnetic field and strain.Finally,aiming at the mechanism of optical fiber magnetic field sensing based on spectral feature recognition,a fiber optic magnetic field response spectrum testing software based on GPIB communication is designed,which realizes real-time monitoring of space environmental magnetic field based on spectral analysis.