Research On 3D Fiber Bragg Grating Anemometer Technology

Ocean is the second space for the survival and development of mankind.As one of the important elements of ocean observation,the accuracy of the data affects the forecast of the ocean,scientific research and investigation of fishery production and port operations.Improve the accuracy of measurement of ocean anemometer,wind speed and direction to enhance the accuracy of observational data is of great significance.However,the existing wind speed measuring equipment in the marine environment has some shortcomings in terms of stability and corrosion resistance and can not meet the long-term and real-time measurement requirements on the ocean.In order to solve this problem,a fiber Bragg grating anemometer is proposed by using the advantages of fiber Bragg grating,such as small volume,corrosion resistance and anti-electromagnetic interference.The main contents of this paper are as follows:The structure design of linkage between the windward baffle and isosceles beam changes the wind speed into the change of strain on the same strength beam.Based on Bragg grating sensing principle and isotropic beam strain theory,a sensing model was established,and the corresponding relationship between wind speed and strain was deduced.Using the reference grating method,two Bragg gratings are written on one fiber and the temperature-compensated Bragg grating is protected from stress by a sensor packaging technique to remove the effect of temperature on the wind speed measurement.Use numerical simulation to optimize the structural design of the sensor.The strain distribution on the strength beam was analyzed by ANSYS finite element software and the optimal installation position of the wind speed sensitive grating was determined.The flow field characteristics of the two geometrical baffles are analyzed and the perturbation of the sensor to the flow field is reduced.The fatigue life of isotropic beam is analyzed,which provides a reference for the long-term working stability of the sensor.The wind speed and temperature compensation fiber grating assembly and packaging technology research,the trapezoidal strain beam structure and the wind deflector structure with concave ring were confirmed.The temperature-compensated grating stainless steel tube capillary single-end fixed-branch package was confirmed,and the isolated package with shielding wind force was realized.Temperature changes caused by fiber grating telescopic changes increase.Test results show that the temperature sensitivity of the grating increased about three times.Respectively,the temperature characteristic test wind speed characteristics test,for anemometer,obtained the sensor's performance index.Wind speed characteristics of the experiment using the method of mounting weights instead of wind,measuring sensor performance,and compared with the wind tunnel test results showed that both the same variation,there is only a slight difference,when 15 m / s wind speed difference is less than 5.91%.The dual-parameter temperature compensation technique for temperature and wind speed of sensor is researched.A two-parameter temperature and wind speed signal processing method is proposed.The experimental results show that the wind speed sensor designed in this paper can accurately detect the change of wind speed and ambient temperature under the action of temperature.The three-dimensional wind speed sensor model is established.The method of three-dimensional wind speed vector synthesis is given and the reliability and validity of the three-dimensional wind speed sensor model are validated.