Research On Measurement Technology Of Aircraft Tank Fuel

The fuel oil measurement in fuel tanks is very important to the fuel system of the aircraft,and it is crucial to ensure flight safety and improve flight quality.The subject of this research is to improve the accuracy of fuel oil measurement in the fuel tank and making the fuel oil measurement timely and accurately.At present,the measurement of fuel volume generally adopts the liquid level sensor to measure the fuel oil level and uses the flight attitude angle to establish a fuel volume characteristic database to correct the attitude error.At the same time,the unreasonable layout of the level measurement sensor in the tank can also lead to the imprecise measurement.This paper improves the measurement accuracy through theses three aspects.It is the key point to measure the oil level precisely in fuel metering systems.With the development of the liquid level measurement,a variety of methods has been applied to the measurement of aircraft oil level.In this paper,a guided wave radar level gauge is designed.And compared to other measurement methods like the capacitive liquid level measurement,this method possesses advantages that it is not affected by the temperature,pressure and foam.The guided wave radar level gauge is based on the reflection characteristic of the electromagnetic wave in the coaxial line,and the time domain reflection principle is used to achieve the liquid level measurement.In addition,it uses the equivalent time sampling to improve the measurement accuracy.This paper introduces the hardware and software design of this guided wave radar level gauge and the functions and implementation methods of each module in detail.In the optimization of the level measurement sensor,this paper analyzes the posture errors generated by rolling and pitching of the irregular fuel tank and the symmetric type fuel tank to find the most suitable placement position with the minimum attitude error.The attitude error is analyzed to find the correction method.The previous methods of stacking and calculating the volume are very complicated and the calculation volume is very large.This paper makes the establishment of the fuel volume characteristic database easier,faster and more accurate by using AutoCAD software.Based on the former works,this paper designs the host computer's fuel measurement and monitoring software using C# language,which can monitor the real-time measurement of the liquid level.And the remaining fuel volume of the fuel tank can be calculated by using the database of fuel volume characteristics.At the same time,the HART communication module is designed to accomplish the communication connection between host computer and slave computer.Finally,an experimental platform is set up to test the guided wave radar level gauges.It proves that all the accuracy,resolution,and repeatability of the liquid level gauge satisfy the requirements of the fuel level measurement of the aircraft.The measuring experiments of the fuel oil quantity are carried out combined with the upper computer software,and the fuel oil quantity can be calculated in real time.