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

摘要

Optical-fibre pressure and temperature sensors have been developed that are suitable for installation in aircraft fuel tanks to monitor on-ground 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 reflectometer (OTDR); three of the sensors measure pressure to allow level measurement with a resolution of 10 mm, while a temperature sensor with an 80 degrees C span provides a resolution of 0.3 degrees C. The temperature measurement allows temperature compensation for the pressure sensors and quantification of fuel mass and weight. (C) 1998 Elsevier Science S.A. All rights reserved. [References: 8]