Application Of Fiber-Optic Fabry-Perot Sensor Inaerodynamics/hydrodynamic Tests

Aerodynamic test is one of the most basic test projects for the development of aerospace and weapons,such as aircrafts,missiles,torpedoes,etc.At present,resistance balances based on foil resistive strain sensors(FR)are used to aerodynamic test in China,however,since the FR sensor has the limitations of large temperature drift,high temperature instability,susceptible to electromagnetic interference,the FR balance is difficult to achieve high test precision in harsh environments.Fiber optic sensors have the advantages of small size,anti-electromagnetic interference,high temperature resistance,fast response,good reliability and high sensitivity,which provide a new idea for exploring new wind tunnel balance force measurement technology.In this paper,an ultra-high sensitivity,low temperature coefficient all-fiber Fabry-Perot sensor(FP)is proposed and applied to different types of force balances for aerodynamic tests of different aircraft and missile models.Among them,a six-component balance based on the FP sensors,has been achieved the aerodynamics tests of the missile standard model at different temperatures in the supersonic wind tunnel.The experimental results show that the fiber balance based on this sensor has a high repetitive temperature compensation coefficient,a high static measurement accuracy of less than 0.4%,and an extremely high linearity of the balance force and the sensors output.In the wind tunnel test with wind speeds of Mach 4(normal temperature)and Mach 8(750K),this fiber balance achieves high-precision measurement of the aerodynamic coefficient of the model,and all states meet and exceed the design index(1.5 %),and the repeatability of most of the tests is less than 1%;and the measured aerodynamic characteristic coefficient with the change of the angle of attack has a good agreement with the normal strain gauge balance test results of the wind tunnel.The 7-bar fiber balances based on the FP sensors has been applied in different application scenarios,such as water tunnel,high-speed wind tunnel,ultra-high-speed wind tunnel,and achieve a long-term stability in high humidity environment,a high-precision measurement in high temperature environment,and solves the high-precision measurement problem under the strong vibration interference environment.