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Sydnie Lieb
Washington University in St. Louis
Professor Richard Axelbaum
Abstract
The boundaries of the region conducive to soot inception in nonpremixed flames are investigated experimentally and numerically. The low temperature boundary represents the minimum temperature required for soot inception to occur in a fuel-rich region, for a given residence time and dilution. The high temperature boundary occurs at a location where the gas composition no longer favors soot particle formation, presumably due to the absence of soot precursors. An earlier analytical model illustrated that when the stoichiometric mixture fraction, Zst, is increased the two boundaries of the soot inception zone move towards each other, until eventually the soot zone collapses and soot inception cannot occur. In this work the results of the analytical model are supported by thin filament pyrometry measurements of flame temperature and laser fluorescence measurements of PAH in counterflow diffusion flames with varying Zst. Consistent with the model, the results demonstrate that the high temperature boundary of the soot zone moves away from the peak temperature zone as Zst is increased and the low temperature boundary moves towards the peak temperature.
Sydnie Lieb is a senior in mechanical engineering at Washington University. Next year she will attend University of Southern California where she will continue working in the field of combustion while she works towards a Phd. in mechanical engineering.
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