Precursor formation and soot inception in premixed ethylene flamers
Absorption, fluorescence and scattering measurements were carried out in rich premixed C(2)H(4)/O(2) flames. Soot and condensed hydrocarbon species concentrations were measured by direct sampling and chemical analysis in the C/O range from 0.65 to 0.75. PAH accounts for no more than 20% of the condensed hydrocarbon species. The early formation in the flames of structures with typical size around 2 nm (2500 a.m.u.), which do not absorb and fluoresce in the visible, was followed by means of ultraviolet scattering and absorption measurements. These transparent particles were considered to be soot precursors on the basis of their decreasing concentration profile in correspondence of soot inception, as evaluated by both optical and chemical measurements. The soot inception process is characterised by the progressive aromatisation of the transparent particles as shown by the progressive shift toward the visible of absorption and fluorescence. The internal rearrangement of a partially aromatic polymeric structure, more than a progressive formation of very large PAH structures, is proposed as a mechanism for soot inception.
Bibliographic Reference: Paper presented: 24th International Symposium on Combustion, Sydney (AU), July 5-10, 1992
Availability: Available from (1) as Paper EN 36914 ORA
Record Number: 199210837 / Last updated on: 1994-12-02
Original language: en
Available languages: en