Design Of An Optical Fiber Sensor For The Aircraft Fuel Measurement System

The plane’s fuel system is one of the key components of a plane, which directly affects its performance and safety. The accuracy of oil measurement is an essential factor of evaluating the fuel system. With the rapid development of modern aviation technology, the aircraft fuel system becomes more and more complex. Consequently, the precision requirement of fuel measurement technology is higher, too. Knowing the amount of oil promptly and precisely has an important sense for finishing the flight task and guaranteeing the safety of flying. However, the plane’s fuel tanks are irregular, which bring a lot of problems for measuring the amount of oil. The accuracy of fuel measurement technology has become a necessary means for improving the system’s reliability.By adopting optical fiber pressure sensor and the principle of liquid pressure, this thesis measures the liquid level for the plane’s fuel tank. The aim is to research a new optical fiber sensor structure and accuracy fuel measuring method, which fits flue measurement of the plane.The chief contents of this paper are as follows:Firstly, based on the mode coupling theory of optical fiber, the macro bending loss coefficient is obtained through perturbation solution of the coupled wave equations between the transmission mode and radiation mode. This paper gives an analysis and design for the system of optical fiber macro bend level sensor.Secondly, this paper conducts the design for the fiber optic liquid level sensor using intensity modulation mode on the principle of macro bending loss. It includes the design for optical ring and the elastic diaphragm, the probe’s overall structure and signal processing circuits.Finally, by using optical fiber macro bending liquid level sensor, the plane’s fuel measurement system is designed, a large number of experiments are conducted. The experiment results verify the system’s sensitivity and accuracy.