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Proceedings Paper

Water vapor measurements for combustion diagnostics using a 1350-nm tunable diode laser
Author(s): Liang-Guo Wang; Richard E. Trucco; Glen William Sachse; Richard E. Campbell; Richard E. Davis
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Paper Abstract

The amount of water vapor formed in scramjet engines in high-enthalpy environments is a key parameter used to infer combustion efficiency. A H2O(V) concentration measurement system for combustion diagnostics in these high-temperature, high-velocity conditions has been developed at the NASA Langley Research Center and tested at General Applied Science Laboratories (GASL) in Ronkonkoma, NY. The system was first tested in an instrumentation shock tunnel using a H2/O2/N2 combustible mixture in the driven section for calibration and development purposes. The system uses a distributed feedback InGaAsP diode laser operating near 1350 nm. A wavelength modulation spectroscopy technique is used to achieve high detection sensitivity. The diode laser is modulated at radio frequency (rf), while the wavelength is scanned over two water vapor absorption lines by injection current tuning at a 5 kHz repetition rate. The detected rf signal is then demodulated at the modulation frequency (one f demodulation). Preliminary experimental results and data analysis are presented.

Paper Details

Date Published: 18 March 1994
PDF: 7 pages
Proc. SPIE 2122, Laser Applications in Combustion and Combustion Diagnostics II, (18 March 1994); doi: 10.1117/12.171289
Show Author Affiliations
Liang-Guo Wang, College of William and Mary (United States)
Richard E. Trucco, General Applied Science Labs., Inc. (United States)
Glen William Sachse, NASA Langley Research Ctr. (United States)
Richard E. Campbell, NASA Langley Research Ctr. (United States)
Richard E. Davis, NASA Langley Research Ctr. (United States)

Published in SPIE Proceedings Vol. 2122:
Laser Applications in Combustion and Combustion Diagnostics II
Randy J. Locke, Editor(s)

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