Photodiode-based sensor for flame sensing and combustion-process monitoring

L. Arias, S.N Torres, Daniel Sbárbaro and Oscar Farías
APPLIED OPTICS 47, 29 (2008)


A nonintrusive low-cost sensor based on silicon photodiode detectors has been designed to analyze the
formation and behavior of excited CH* and C2* radicals in the combustion process by sensing the spectral
emission of hydrocarbon flames. The sensor was validated by performing two sets of experiments for both
nonconfined and confined flames. For a nonconfined oil flame, the sensor responses for the axial intensity
were highly correlated with the measurements obtained with a radiometer. For confined gas flames the
ratio between the signal corresponding to C2* and CH* was successfully correlated with the CO pollutant
emissions and the combustion efficiency. These results give additional insight on how to prevent an incomplete
combustion using spectral information. The fast response, the nonintrusive character, and the
instantaneous measurement of the needed spectral information makes the proposed optical sensor a key
element in the development of advanced control strategies for combustion processes.
© 2008 Optical Society of America