Quantitative two-dimensional laser diagnostics in idealized and practical combustion systems

Two-dimensional laser diagnostics are used to investigate a variety of combustion environments, ranging from simple laminar diffusion flames to internal combustion engines. A new spontaneous Raman technique, difference Raman scattering, is developed to minimize the problems caused by fluorescence interference on Raman scattering in hydrocarbon flames, and is used to perform quantitative major species and temperature measurements in a nitrogen-diluted methane/air diffusion flame. In the same flame, absolute nitric oxide concentrations are measured using quench corrected laser-induced fluorescence imaging. These results are compared to a two-dimensional numerical model of this flame that incorporates both C, and full nitrogen chemistry.;Lastly, ketone fluorescence imaging is used to understand the behavior of crevice hydrocarbon emissions in a specially modified, optically accessible integral combustion engine. Several well characterized crevices located within the engine are used to asses the impact of crevice size, engine load, wall temperature, fuel volatility, and fuel reactivity on crevice hydrocarbon emissions.;The effect of combustion on ketone fluorescence yields is evaluated in laminar, ketone-doped methane/air diffusion flames. Difference Raman fully characterizes the major species and temperature in three flames doped with different ketones (acetone, 2-butanone, and 3-pentanone), while spectrally resolved fluorescence from these ketones is obtained using three different excitation wavelengths (266 nm, 308 nm, and 320 nm). From this data, quantitative information on how the flame alters the fluorescence yield is derived.