Optical measurement of the fuel quantity in aircrafts provides several advantages compared to the established ultrasonic and capacitive measurement methods. These advantages comprise increased safety, increased accuracy and considerably lower maintenance cost. However, several technological challenges have to be faced when an optical measurement system is to be made airworthy. This paper deals with the methods, environmental and commercial aspects of optical fuel measurement systems in aircrafts. Two measurement methods, differential absorption level gaging and polarization based density measurement by measuring the optical refractive index , are presented in detail. While optical measurement of the level and density of kerosene in aircraft tanks offers advantages compared to standard methods, several issues have to be addressed to get an optical measurement system airworthy. We have shown the technical and environmental challenges and presented each a method for optical measurement of the fuel level and for measuring the fuel density. Both methods have in common that they neither need electrical energy nor environment-sensitive devices inside or near the fuel tanks. In addition, standard components (e.g. laser diodes, LEDs) can be used, which considerably reduces the cost of such a measurement system. Further, electro-magnetic compatibility is enhanced significantly. Both measurement methods showed good accuracy, and both are robust and - relatively- simple technologies suitable for use in harsh environments. This also implies reduced maintenance costs compared to the systems used in today's aircrafts. The measurement systems are also suitable for the measurement and characterization of other liquids than fuel, e.g. water, lubricants or cooling agents.
Optical fuel quantity measurement in aircrafts
2007
10 Seiten, 7 Bilder, 7 Quellen
Conference paper
English
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