Multiple microbending optical-fibre sensors for measurement of fuel quantity in aircraft fuel tanks

• Published in: Sensors and actuators. A, Physical Vol. 68; no. 1; pp. 320 - 323
• Main Authors: Knowles, S.F., Jones, B.E., Purdy, S., France, C.M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 15.06.1998; Elsevier Science
• Subjects: Exact sciences and technology; Fiber-optic instruments; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Measurements common to several branches of physics and astronomy; Metrology, measurements and laboratory procedures; Optical fibres; Optical instruments, equipment and techniques; Physics; Pressure; Sensors; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Spatial dimensions (e.g.: position, lengths, volume, angles, displacements, including nanometer-scale displacements); Spatial dimensions (eg, position, lengths, volume, angles, displacements, including nanometer-scale displacements); Temperature; Temperature; Sensors; Pressure; Optical fibres; Optical fibers; Microbending; Experimental study; Level measurement; Reflectometers
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/S0924-4247(98)00030-2

Optical-fibre pressure and temperature sensors have been developed that are suitable for installation in aircraft fuel tanks to monitor onground fuel quantity. The pressure sensors employ cylindrical microbending structures, and are subject to the liquid pressure through expanding bellows mounted at the bottom of the fuel tank, A 2.5 m variation in fuel level causes a 3 dB change in the light intensity through a microbending sensor. In a demonstrator, four sensors are distributed along a single optical fibre and interrogated using an optical time-domain refiectometer (OTDR); three of the sensors measure pressure to allow level measurement with a resolution of 10 mm, while a temperature sensor with an 80 °C span provides a resolution of 0.3 °C. The temperature measurement allows temperature compensation for the pressure sensors and quantification of fuel mass and weight.