Possibilities of NOx on-line control by using degenerate four wave mixing spectroscopy on intermediate species

Roberta Fantoni, Luigi De Dominicis, Mariano Giorgi, Dmitri A. Sidorov Biryukov, Massimo D'Apice, Stefano Giammartini

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The DFWM (Degenerate Four Wave Mixing), used as a laser spectroscopy for gas phase trace detection, is receiving a great deal of attention for on-line applications in industrial combustion diagnostics. Low release of NOx requires a complete control of nascent NO formation, i.e. of the combustion chemistry involving the OH radical, and space resolved temperature measurements on each species. Both NO and OH have been detected on small hydrocarbon/air flames by DFWM in forward BOXCARS geometry. NO distribution has been investigated by exciting the γ band, temperature and concentration have been calculated after spectral simulation and calibration on doped flames. OH spectra of the A2Σ+- X2Π, on the fundamental (0,0) and first vibrationally excited transition (1,0), have been used to monitor the radical space distribution and its temperature. Line broadening, shifting and intensity borrowing phenomena related to saturation have been investigated in order to correctly model the spectra. The technique has been used to detect OH (1,0) band in the combustion chamber of a dry low NOx 130 KW prototype burner, obtaining relative OH concentration profiles. A single shot broad band system, contemporary detecting a few OH lines in the (0,0) transition, has been built to operate in turbulent regime.
Original languageEnglish
Pages (from-to)68 - 79
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 1999
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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