Laser-induced incandescence (LII)
(measurement of soot volume fraction and soot particle size)



Laser-induced incandescence permits quantitative determination of soot volume fractions when the method is calibrated using extinction measurements. Applied as light-section method in single-shot technique, instantaneous soot distribution can be measured in flames by LII. One of our fields of application is the investigation of gas turbine-specific high-pressure flames. In combustion chambers of aero engines soot is formed in the primary flame zone, which is then mostly oxidized by injection of secondary air before the burned gas enters the turbine. Therefore, in addition to soot formation, the mechanisms of soot oxidation are an important aspect of our research work. By the combination with measurement techniques for the flow velocities (Particle Image Velocimetry), the temperature distribution (coherent anti-Stokes Raman scattering) and the flame structures (laser-induced fluorescence) the LII results form a comprehensive database for the validation of numerical simulations.

 Simultaneously measured distributions of soot concentrations and OH radicals in a turbulent swirl flame.
zum Bild Simultaneously measured distributions of soot concentrations and OH radicals in a turbulent swirl flame.

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