FLAME IMAGE PROCESSING AND ANALYSIS IN AN ULTRA-LEAN LIQUID FUELED COMBUSTOR

The design of lean gas turbine combustion system requires a deep understanding of the instabilities that are evident at conditions close to the lean blowout limit. Furthermore the development of partially-premixed combustors, with multiple injection points, is particularly promising to reach the limitation of pollution. In the present work different experimental diagnostic techniques were used for characterizing unstable combustion in presence of non premixed and partially premixed flames. The applied techniques include OH* chemiluminescence acquisitions using a photomultiplier system, broadband visible and infrared optical emissions using two high rate CCD cameras and finally pollutant measurements using a multispecies exhaust gas measurements system. Several statistical and spectral post-processing methods were implemented to characterize the unstable combustion mechanisms and to permit the development of control strategies in lean premixed gas turbine combustors.