Structure of overfire soot in buoyant turbulent diffusion flames at long residence times

Journal Article · Fri May 01 00:00:00 EDT 1992 · Combustion and Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(92)90024-J· OSTI ID:5183877

Koeylue, U O; Faeth, G M ^[1]

---

1. Dept. of Aerospace Engineering, Univ. of Michigan, Ann Arbor, MI (US)

This paper reports on the structure of soot within the fuel-lean (overfire) region of overventilated buoyant turbulent diffusion flames burning in still air. The study was limited to the long residence time regime where characteristic flame residence times are roughly more than an order of magnitude longer than the laminar smoke point residence time and soot generation factors (the mass of soot emitted per unit mass of fuel carbon burned) are relatively independent of flame residence times. Both gaseous and liquid fuels were used to provide a range of H/C ratios (1-2.7) and fuel types (alkynes, alkenes, alkanes, aromatics, and alcohols) as follows: toluene, acetylene, benzene, propylene, ethylene, n-heptane, propane, and isopropanol. Measurements included transmission electron microscopy to find primary particle diameters, the number of primary particles per aggregate and aggregate geometrical and fractal dimensions. The results show that the structure of soot varies with fuel type but is relatively independent of both position in the overfire region and flame residence time for the long residence time regime. Mean primary particle diameters were 30-51 nm and the mean number of primary particles per aggregate were 255-552, with the larger values associated with the more heavily sooting fuels.

• OSTI ID: 5183877
• Journal Information: Combustion and Flame; (United States), Journal Name: Combustion and Flame; (United States) Vol. 89:2; ISSN 0010-2180; ISSN CBFMA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
ACETYLENE
AEROSOLS
AIR
ALCOHOLS
ALKANES
ALKENES
ALKYLATED AROMATICS
ALKYNES
AROMATICS
BENZENE
COHERENT SCATTERING
COLLOIDS
DIFFUSION
DISPERSIONS
ELECTRON MICROSCOPY
FLAMES
FLUID FLOW
FLUIDS
FUEL GAS
FUELS
GAS FUELS
GASES
HYDROCARBONS
HYDROXY COMPOUNDS
LAMINAR FLOW
LIQUIDS
MICROSCOPY
MIXTURES
ORGANIC COMPOUNDS
RAYLEIGH SCATTERING
RESIDUES
SCATTERING
SMOKES
SOLS
SOOT
TOLUENE
TRANSMISSION ELECTRON MICROSCOPY
TURBULENCE