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Proceedings Paper

Fiber optic microsensor technology for detection of hydrogen in space applications
Author(s): Alex A. Kazemi
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Paper Abstract

Optical hydrogen sensors are intrinsically safe since they produce no arc or spark in an explosive environment caused by the leakage of hydrogen. Safety remains a top priority since leakage of hydrogen in air during production, storage, transfer and distribution creates an explosive atmosphere for concentrations between 4% (v/v) - the lower explosive limit (LEL) and 74.5% (v/v) - the upper explosive limit (UEL) at room temperature and pressure. Being a very small molecule, hydrogen is prone to leakage through seals and micro-cracks. Hydrogen detection in space application is very challenging; public acceptance of hydrogen fuel would require the integration of a reliable hydrogen safety sensor. For detecting leakage of cryogenic fluids in spaceport facilities, Launch vehicle industry and aerospace agencies are currently relying heavily on the bulky mass spectrometers, which fill one or more equipment racks, and weigh several hundred kilograms. This paper describes the successful development and test of a multi-point fiber optic hydrogen sensor system during the static firing of an Evolved Expandable Launch Vehicle at NASA's Stennis Space Center. The system consisted of microsensors (optrodes) using hydrogen gas sensitive indicator incorporated onto an optically transparent porous substrate. The modular optoelectronics and multiplexing network system was designed and assembled utilizing a multi-channel optoelectronic sensor readout unit that monitored the hydrogen and temperature response of the individual optrodes in real-time and communicated this information via a serial communication port to a remote laptop computer. The paper would discuss the sensor design and performance data under field deployment conditions.

Paper Details

Date Published: 28 April 2008
PDF: 9 pages
Proc. SPIE 7003, Optical Sensors 2008, 70032E (28 April 2008); doi: 10.1117/12.778264
Show Author Affiliations
Alex A. Kazemi, The Boeing Co. (United States)

Published in SPIE Proceedings Vol. 7003:
Optical Sensors 2008
Francis Berghmans; Anna Grazia Mignani; Antonello Cutolo; Patrick P. Meyrueis; Thomas P. Pearsall, Editor(s)

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