Time resolved laser induced incandescence for soot and cenospheres measurements in oil flames

The quantitative characterization of sooting flames in terms of soot load a nd total soot surface area continues to be a major challenge in both fundam ental investigations and practical applications. More particularly, a major interest can be found to discriminate the two classes of particulate, name ly soot and cenosphere, presents in power generation plants fuelled with he avy fuel oils. The Laser-Induced Incandescence (LII) technique is widely employed for the determination of soot volume fraction but LII may also be used to derive th e particle diameter, profiting from the size-dependent cooling behavior of the laser-heated particles. The temporally resolved LII emissions has been successfully used in a heavy fuel oil spray flame to distinguish the two cl asses of carbonaceous particles produced during the heavy fuel oil combusti on. Moreover, it has been possible to follow along the flame axis the forma tion and burn-out of these two classes of particulate and their relative am ount in terms of volume fraction.