Water detection in jet fuel using a polymer optical fibre Bragg grating

Chi Zhang, Xianfeng F. Chen, David J. Webb, Gang-Ding Peng

Research output: Chapter in Book/Published conference outputChapter


Water is a common impurity of jet fuel, and can exist in three forms: dissolved in the fuel, as a suspension and as a distinct layer at the bottom of the fuel tank. Water cannot practically be eliminated from fuel but must be kept to a minimum as large quantities can cause engine problems, particularly when frozen, and the interface between water and fuel acts as a breeding ground for biological contaminants. The quantities of dissolved or suspended water are quite small, ranging from about 10 ppm to 150 ppm. This makes the measurement task difficult and there is currently a lack of a convenient, electrically passive system for water-in-fuel monitoring; instead the airlines rely on colorimetric spot tests or simply draining liquid from the bottom of fuel tanks. For all these reason, people have explored different ways to detect water in fuel, however all these approaches have problems, e.g. they may not be electrically passive or they may be sensitive to the refractive index of the fuel. In this paper, we present a simple, direct and sensitive approach involving the use of a polymer optical fibre Bragg grating to detect water in fuel. The principle is that poly(methyl methacrylate) (PMMA) can absorb moisture from its surroundings (up to 2% at 23 °C), leading to both a swelling of the material and an increase in refractive index with a consequent increase in the Bragg wavelength of a grating inscribed in the material.
Original languageEnglish
Title of host publication20th international conference on optical fibre sensors
EditorsJulian Jones, Brian Culshaw, Wolfgang Ecke, José M. López-Higuera, Reinhardt Willsch
Number of pages4
Publication statusPublished - Oct 2009
Event20th International Conference on Optical Fibre Sensors - Edinburgh, United Kingdom
Duration: 5 Oct 20099 Oct 2009

Publication series

NameSPIE proceedings
ISSN (Print)0277-786X


Conference20th International Conference on Optical Fibre Sensors
Country/TerritoryUnited Kingdom
OtherThe International Conference on ‘Optical Fibre Sensors’ is acknowledged as the world’s leading conference on all topics related to fibre-optic, guided-wave and optical sensing devices, systems, theories and techniques for research and applications.

Bibliographical note

Zhang, C., Chen, X. F., Webb, D. J., & Peng, G-D., " Water detection in jet fuel using a polymer optical fibre Bragg grating", 20th international conference on optical fibre sensors, Jones, J., Culshaw, B., Ecke, W., López-Higuera, J. M., & Willsch, R., 7503, 750380, (2009).
Copyright 2009 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.


  • water
  • impurity
  • jet fuel
  • engine
  • biological contaminants
  • electrically passive system
  • water-in-fuel monitoring
  • colorimetric spot tests
  • detect water in fuel
  • refractive index
  • fuel
  • polymer optical fibre Bragg grating
  • water in fuel


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