Diffusion flames coflow

Calculated species mole fractions, temperature, and heat-release rate across a gaseous n-heptane diffusion flame (18 mm o.d., fuel velocity 0.1 cm/s) in coflowing air (velocity 10.7cm/s) at a height of 10.8mm inly. 

Walsh, K.T., Fielding, J., Smooke, M.D., and Long, M.B., Experimental and computational study of temperature, species, and soot in buoyant and non-buoyant coflow laminar diffusion flames, Proc. Combust. Inst., 28, 1973, 2000. 

In Chapter 8.1, F. Takahashi presents candle and laminar jet diffusion flames highlighting fhe physical and chemical mechanism of combustion in a candle and similar laminar coflow diffusion flames in normal gravity and in microgravity. This apparently simple system turns out to be very complex, and thereby its study is of greaf importance for the understanding of diffusion flame fundamentals. 

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],... 

Early work on premixed Bunsen flames and coflowing diffusion flames [69-71] was repeated in experiments where the temperature was controlled by varying... 

K. Prasad, C. Li, K. Kailasanath Optimizing water-mist injection characteristics for suppression of coflow diffusion flames, 27th Symposium (Intemational) on Combustion, pp. 2847-2855, Combustion Institute, Pittsburgh (1998). 

The idea is to feed the vaporized metal precursor into a flame in the presence of oxygen the heat evolved by combustion of the fuel decomposes the precursor, forming the oxide. For instance, nitrogen saturated with TiCU at 90 °C is mixed with air and fed into a H2-O2 coflow diffusion flame, producing titania particles [52] by using different O2 partial pressures (N2-O2 mixtures), particles with different properties (anatase content, crystallite size, SSA, etc.) can be prepared [53]. 

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