Simultaneous planar laser-induced incandescence, OH planar laser-induced fluorescence, and droplet Mie scattering in swirl-stabilized spray flames

Abstract

Simultaneous planar laser-induced incandescence, hydroxyl radical planar laser-induced fluorescence, and droplet Mie scattering are used to study the instantaneous flame structure and soot formation process in an atmospheric pressure, swirl-stabilized, liquid-fueled, model gas-turbine combustor. Optimal excitation and detection schemes to maximize single-shot signals and avoid interferences from soot-laden flame emission are discussed. The data indicate that rich pockets of premixed fuel and air along the interface between the spray flame and the recirculation zone serve as primary sites for soot inception. Intermittent large-scale structures and local equivalence ratio are also found to play an important role in soot formation.

Soot Formation and Flame Characterization of an Aero-Engine Model Combustor Burning Ethylene at Elevated Pressure

“…The photo (left) is close to the visual impression, however with a relatively short exposure time of 500/is. In the lower part of the combustion chamber, this region coincides largely with the inner recirculation zone where hot exhaust gases containing unburned hydrocarbons come into contact with fresh gases and the flame zone [4]. Luminous soot is visible over large regions of the combustion chamber with lower intensities close to the nozzle.…”

Investigation of soot formation in pressurized swirl flames by laser measurements of temperature, flame structures and soot concentrations

“…Suitable experiments to bridge the gap towards technical combustion are highly demanded. Measurements of soot concentrations and further quantities in gas turbine relevant flames have been performed, for example, by Lammel et al [8] and Meyer et al [9]. However, the results from those experiments are of limited amount or the combustor is too complex for model validation.…”

Measurement of aerosol size distribution function using Mie scattering—Mathematical considerations

“…However, tuning of the light sources over a wide spectral range limits the time response of these techniques and also complicates the data analysis due to the variation of refractive index over wide ranges of wavelengths. Rapid and continuous measurement is highly desirable in many applications, such as the study of spray combustion (Grassmann & Peters, 2004;Meyer, Roy, Belovich, Corporan, & Gord, 2005;Tishkoff, Hammond, & Chraplyvy, 1982;Winklhofer & Plimon, 1991) and the fast formation/evaporation of aerosols (Vandongen, Smolders, Braun, Snoeijs, & Willems, 1994). Such measurement needs motivate the development of the second category of methods, which relies on scattering data at a single wavelength or a limited number of discrete wavelengths.…”