Measurement of CO2 concentration and temperature in an aero engine exhaust plume using wavelength modulation spectroscopy

Thomas Benoy, David Wilson, Michael Lengden, Ian Armstrong, George Stewart, Walter Johnstone

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In this paper, the 2f/1f tunable diode laser wavelength modulation technique is used for the simultaneous measurement of concentration and temperature of CO2 in the exhaust plume of an aero engine. The suitability of the R48 spectral feature of CO2 at 1997.2 nm is discussed for this application and for further investigations into the application of CO2 tomographic imaging on large-scale aero-engines. To ensure accurate recovery of gas parameters at the high exhaust temperatures a full spectral characterisation of the spectral feature is presented using direct spectroscopy. The 2f/1f method is validated in the laboratory for controlled gas mixtures and temperatures to recover concentration and temperature, showing good agreement with the actual temperature and concentration values. Finally, single path measurements are presented for an aero engine exhaust showing good correlation with the measured engine conditions.
Original languageEnglish
Pages (from-to)6409-6417
Number of pages9
JournalIEEE Sensors Journal
Issue number19
Early online date11 Aug 2017
Publication statusPublished - 1 Oct 2017



  • laser spectroscopy
  • optical sensors
  • combustion diagnostics
  • aero engine exhaust plumes
  • TDLS
  • wavelength modulation spectroscopy
  • optical tomography
  • aerospace engineering

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