On the spectral bands measurements for combustion monitoring

L. Arias, S.N Torres, Daniel Sbárbaro and Philippe Ngendakumana


In this work, spatial–spectral experimental issues affecting the detection of radical emissions in a natural
gas flame are discussed and studied by a radiometric analysis of the flame spectral emission. As results of
this analysis, Local and Global Spectral Radiation Measurements (LSRM and GSRM respectively) techniques
are proposed, and guidelines for selecting the radical emission bands and spatial location of
photodetectors are given. Two types of experiments have been performed in order to demonstrate the
reliability of the GSRM technique for combustion characterization. In the first experiment, the LSRM
and the GSRM have been implemented by using a home made sensor array, based on silicon photodiodes,
for sensing the excited CH* and C2* radicals in a natural gas flame. It has been experimentally demonstrated
that by using the GSRM, the signal’s dispersion can be reduced to about 86% for the CH* and
76% for the C2* with respect to the obtained values with LSRM methodology. In the second experiment,
the GSRM technique has been applied for sensing the CH* and C2* radicals, where it has been found that
the signals emissions ratio C2*/CH* provides a good indicator of the thermal combustion efficiency and the
CO pollutants emissions, with small dispersion. Thus, the GSRM technique has corroborated the usefulness
of that ratio for combustion monitoring.

DOI: http://dx.doi.org/10.1016/j.combustflame.2010.09.018