Soot growth

Fundamental investigations of soot growth and oxidation were performed by many researchers in both diffusion and premixed flames with ethene and methane as fuels (see, e.g., Santoro and Shaddix, 2002 Schulz et al., 2006). 

Fig. 10 Schematic of soot growth from fuel molecules through PAH. (From Bockhom, 1994.)...

We have shown that the acetylene in the burned gases is the source for most of the mass of mature soot particles. Furthermore, we have found that the measured growth rates are consistent with the assumption that a first order decomposition reaction of acetylene with the soot surface is responsible for most of the soot growth, although diacetylene may also play some role. 

A large number of polycyclic aromatic hydrocarbons are known Many have been synthesized m the laboratory and several of the others are products of com bustion Benzo[a]pyrene for example is present m tobacco smoke contaminates food cooked on barbecue grills and collects m the soot of chimneys Benzo[a]pyrene is a carcinogen (a cancer causing substance) It is converted m the liver to an epoxy diol that can induce mutations leading to the uncontrolled growth of certain cells... 

The composition, properties, and size of soot particles collected from flame products vary considerably with flame conditions and growth time. Typically the C—H atomic ratio ranges from two to five and the particles consist of kregular chains or clusters of tiny spheres 10—40 nm in diameter with overall dimensions of perhaps 200 nm, although some may agglomerate further to much larger sizes. 

Richter, H. and Howard, J.B., Formation of polycyclic aromatic hydrocarbons and their growth to soot—a review of chemical reaction pathways, Prog. Energy Combust. Sci., 26,565,2000. 

Heat flux is an important variable in fire growth and its determination is necessary for many problems. In general, it depends on scale (laminar or turbulent, beam length ), material (soot, combustion products) and flow features (geometric, natural or forced). We... 

It should be emphasized that mankind has come and still comes into contact with fullerene in everyday life. Pristine fullerene C60 itself can be found in our environment, e.g., in the soot produced by free burning of hydrocarbons like benzene and cyclohexane, as well as in charcoal, though in very small amounts (Shibuya et al., 1999) and in the kitchen (in natural gas combustion streams) (Bang et al., 2004 Murr and Soto, 2005). The impact of these natural sources is rather negligible though with the growth of production of fullerenes it could lead to much more serious environment pollution and be (or could not ) of a hazard to some extent. 

It is a chemical challenge to initiate the growth of BSU such that they all adhere to the carbon fiber filler. If unsuccessful, soot particles may result. These may form a granular non-interacting second phase which strongly counteracts the intended effect of... 

For premixed fuel-air systems, results are reported in various terms that can be related to a critical equivalence ratio at which the onset of some yellow flame luminosity is observed. Premixed combustion studies have been performed primarily with Bunsen-type flames [52, 53], flat flames [54], and stirred reactors [55, 56], The earliest work [57, 58] on diffusion flames dealt mainly with axisymmetric coflow (coannular) systems in which the smoke height or the volumetric or mass flow rate of the fuel at this height was used as the correlating parameter. The smoke height is considered to be a measure of the fuel s particulate formation and growth rates but is controlled by the soot particle bumup. The specific references to this early work and that mentioned in subsequent paragraphs can be found in Ref. [50],... 

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