Comparative Study on Nascent Soot Formation Characteristics in Laminar Premixed Acetylene, Ethylene, and Ethane Flames

Abstract

The sooting behavior in the laminar premixed flames of acetylene, ethylene, and ethane was studied both experimentally and computationally to explore the effect of fuel structure on nascent soot formation. The particle size distributions were measured using an orifice sampling technique coupled with a scanning mobility particle sizer. The particle morphology was examined using a nanometer aerosol sampler coupled with a transmission electron microscope. Numerical simulations of soot volume fraction and gas species concentrations were carried out to analyze the experimental observations. At the same C/O ratio of 0.667 and maximum temperature of around 1790 K, the ethane flame shows the highest rates of nucleation and mass growth among the three C2 flames, while much fewer and smaller particles are observed in the acetylene flame than those in the ethylene and ethane flames. Simulation results indicate soot volume fraction is very sensitive to the nucleation rate, while surface reactions only play a role at higher flame heights. All three flames share reaction paths similar to benzene, whereas some oxidation reactions are more dominant in the acetylene flame due to the lower equivalence ratio that inhibits soot formation.

Hydrogen, sp2 Carbon Hybridization, and sp2 Clustering as Pieces of the Puzzling Nanostructure of Soot: A Closer Look

“…Definitely, OC components, although they may be relevant as soot precursors, can obscure the analysis of soot nanostructure, especially in the first phase of soot formation. Consequently, the coexistence in the carbon PM of species with such different compositional properties (Figure ) and sizes (Figure ), along with the variability of soot and OC contributions in dependence on the source conditions (fuel type, feed ratio, mixing , ), necessitates their preseparation by extraction followed by implementation of different careful diagnostic approaches to get as much data as possible to be crossed for facing soot structural complexity.…”

Numerical and Experimental Investigation of Soot Suppression by Acoustic Oscillated Combustion

“…Soot models are under continuous improvement from empirical to semi-empirical and then detailed. Detailed models ,− ,− use detailed chemical kinetic mechanisms to describe the formation of PAHs and soot, and thus they are expensive in the computational cost. Semi-empirical models − usually include the processes of inception, surface growth, oxidation, and particle coagulation.…”