Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Mechanical Engineering

First Advisor

Tryfon T. Charalampopoulos


In-situ light scattering measurements are combined with chemical analysis of sampled soot particles to elucidate the mechanisms through which iron addition affects soot formation and growth processes in fuel-rich, premixed propane and oxygen flames. Soot particle optical inhomogeneity resulting from the addition of iron is accounted for in the light scattering analysis using an effective refractive index model. The influence of iron addition on soot particle diameters, number densities, volume fractions, surface areas, and specific growth rates is investigated. In addition, X-ray photoelectron spectroscopy was used to determine the chemical state of iron species throughout the flame. The analysis revealed that the iron oxide Fe$\sb2$O$\sb3$ is the only dominant species within the soot particles, corresponding to residence times from 10 to 32 milliseconds. The influence of iron addition on soot particle parameters is assessed and the important reaction mechanisms involving iron in sooting flames are discussed. It is proposed that Fe$\sb2$O$\sb3$ catalysis of carbon oxidation by oxygen to carbon monoxide and carbon dioxide in the soot burnout zone is the primary soot suppressing mechanism of iron in flames.