This report summarizes technical progress on the program Multiplexed Optical Fiber Sensors for Coal Fired Advanced Fossil Energy Systems funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed jointly by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering and the Department of Materials Science and Engineering at Virginia Tech. This three-year project started on October 1, 2008. In the project, a fiber optical sensing system based on intrinsic Fabry-Perot Interferometer (IFPI) was developed for strain and temperature measurements for Ultra Supercritical boiler condition assessment. Investigations were focused on sensor design, fabrication, attachment techniques and novel materials for high temperature and strain measurements. At the start of the project, the technical requirements for the sensing technology were determined together with our industrial partner Alstom Power. As is demonstrated in
- Chapter 4, all the technical requirements are successfully met. The success of the technology extended beyond laboratory test
its capability was further validated through the field test at DOE NETL, in which the sensors yielded distributed temperature mapping of a testing coupon installed in the turbine test rig. The measurement results agreed well with prior results generated with thermocouples. In this project, significant improvements were made to the IFPI sensor technology by splicing condition optimization, transmission loss reduction, sensor signal demodulation and sensor system design.