Fundamental flame studies of soot formation at high pressures and at low gravity

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Soot aerosols affect the Earth's temperature and climate, both regionally and globally by altering the radiative properties of the atmosphere. The contribution to global warming may be substantial, perhaps second only to that of carbon dioxide. In addition, the deposition of soot on snow and ice reduces the surface reflectivity thus trapping the radiation; this could be responsible for a quarter of the global warming. The Intergovernmental Panel on Climate Change indicated that the soot aerosol is the third largest contributor to the positive radiative forcing that causes climate change. Furthermore, exposure to soot aerosol is responsible for hundreds of thousands of global deaths each year. Controls on soot aerosol can produce rapid regional and global climate benefits as well as reductions of ill effects on human health. One of the approaches in control is prevention or reduction of soot generation in combustion. A significant portion of soot is emitted from combustion engines used in land, air and sea transportation. A fundamental understanding of the soot formation processes in combustion is an integral part of this control approach. However, the details of the soot formation process in combustion remain uncertain due to the highly complex nature of hydrocarbon flames. In spite of the fact that most combustion devices used for transportation operate at very high pressures, our understanding of soot formation at high pressures is very limited, and there is a fundamental lack of experimental data and complementary predictive models. Sooting characteristics of liquid bio-fuels are not known well, especially at high pressures where most engines operate, and this lack of understanding has implications in adopting bio-fuels and blends in gas turbines and other land transportation engines. The current proposal aims to address these issues by contributing to the advancement of knowledge in soot formation and helping with the soot emissions control efforts. This will be accomplished by carefully planned experiments using the unique high-pressure combustion facility and optical combustion diagnostics available at UTIAS.