Soot morphology in a laminar counter-flow diffusion flame derived from RDG/PFA technique

Diesel engines consume the majority of the injected fuel in turbulent, diffusion-controlled combustion processes. Inefficiencies in these complex and coupled processes lead to the formation of soot and other pollutants. In addition to decreasing engine efficiency, soot particles have been shown to be harmful to human beings, being both carcinogenic and mutagenic. The biological hazards posed by these particles are a function of their morphology. These particles also have a much stronger thermal signature compared to gas phase products, water and carbon dioxide, and render Diesel-powered vehicles susceptible to tracking and targeting via IR sensors. This IR signature will decay with time as the particles cool, and this temporal profile is a function of the morphology of the soot. Therefore, there is a strong demand to understand the morphology of soot generated in various combustion environments in addition to the soot volume fraction. We report spatially resolved measurements of soot morphology in both laminar co-flow and counter-flow diffusion flames. This morphology includes volume fraction, average primary particle size, number of primary particles per agglomerate and its standard deviation, and the mass fractal dimension, as provided by RDG/PFA technique.