The demand for better understanding of the mechanism of soot formation is driven by the negative environmental and health impact brought about by the burning of fossil fuels. While soot particles accumulate most of their mass from surface reactions, the mechanism for surface growth has so far been characterized primarily by measurements of the kinetics. Here we provide atomic-scale scanning tun...

JP-8, a surrogate fuel, and several model compounds were used to produce soot aerosols in a drop-tube furnace with optical access. The soluble organic fractions (SOF) of soot aerosols were studied with GC, GC-MS, and 13C NMR. The residue of each aerosol sample was studied with Raman spectroscopy, ESR, and a recently developed technique used to determine the conductivity and extent of turbostrat...

act— A CFD-based numerical model has been ed for the determination of the volume concentration ber density of soot in a laminar diffusion flame of in air, under transient condition following ignition of e. The transience is studied from the point of ignition final steady state is reached. The burner is an axiric co-flowing one with the fuel issuing through a port and air through an annular port...

Particulate matter (soot aerosol or carbon black) emissions from combustion systems have adverse effects on human health and the environment. Soot is a major contributor to the total radiation heat loss in propulsion systems. Soot aerosols in the atmosphere have significant positive radiative forcing that contributes to global warming because of strong absorption of sunlight by soot. As compare...

Most liquid fuels contain compounds with one or more unsaturated CC bonds. Previous studies have observed that the fuel reactivity and ignition behavior are strongly influenced by the presence and number of double bonds in the fuel molecular structure. Here, we report a numerical investigation on the effect of fuel unsaturation on PAHs and soot emissions in partially premixed flames (PPFs) bur...

Soot particles, which are aggregated carbonaceous spherules with graphitic structures, are major aerosol constituents that result from burning of fossil fuel, biofuel, and biomass. Their properties commonly change through reaction with other particles or gases, resulting in complex internal mixtures. Using a transmission electron microscope (TEM) for both imaging and chemical analysis, we measu...

A semiempirical model has been developed for predicting coal-derived soot. The main feature of the model is a transport equation for soot mass fraction. Tar prediction options include either an empirical or a transport equation approach, which directly impacts the source term for soot formation. Also, the number of soot particles per unit mass of gas may be calculated using either a transport e...

Soot particles are ubiquitous in the atmosphere and have important climatic and health effects. The aging processes of soot during long-range transport result in variability in its morphology, microstructure, and hygroscopic and optical properties, subsequently leading to the modification of soot's climatic and health effects. In the present study the aging process of soot by molecular O(2) und...

A sooting, ethylene coflow diffusion flame has been studied both experimentally and computationally. The fuel is diluted with nitrogen and the flame is slightly lifted to minimize the effects of the burner. Both probe (thermocouple and gas-sampling techniques) and optical diagnostic methods (Rayleigh scattering and laser-induced incandescence) are used to measure the temperature, gas species, a...

Adverse health effects of airborne toxicants, especially small respirable particles and their associated adsorbed chemicals, are of growing concern to health professionals, governmental agencies, and the general public. Areas rich in petrochemical processing facilities (e.g., eastern Texas and southern California) chronically have poor air quality. Atmospheric releases of products of incomplete...