First Demonstration Of An Acousto-Optically Modulated Quantum Cascade Laser As A Broadband, Time-Resolved Combustion Diagnostic

Abstract

We provide the first demonstration of an acousto-optically modulated quantum cascade laser (AOM QCL) system as a diagnostic for combustion by measuring nitric oxide (NO), a highly-regulated emission produced in gas turbines. The system provides time-resolved broadband spectral measurements of the present gas species via a single line of sight measurement, offering advantages over widely used narrowband absorption spectroscopy (e.g., the potential for simultaneous multi-species measurements using a single laser) and considerably faster (>15kHz rates and potentially up to MHz) than sampling techniques which employ FTIR or GC/MS. The developed AOM QCL system yields fast tunable output covering a spectral range of 1725 - 1930 cm-1 with a linewidth of 10-15 cm-1. For the demonstration experiment, the AOM QCL system has been used to obtain time-resolved spectral measurements of NO formation during the shock heating of mixture of a 10% nitrous oxide (N2O) in a balance of argon over a temperature range of 1245 - 2517 K and a pressure range of 3.6 - 5.8 atm. Results were in good agreement with chemical kinetic simulations. The system shows revolutionary promise for making simultaneous time-resolved measurements of multiple species concentrations and temperature with a single line of sight measurement.

Publication Date

1-1-2018

Publication Title

Proceedings of the ASME Turbo Expo

Volume

4A-2018

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.1115/GT201875424

Socpus ID

85054049480 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85054049480

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