Comparison of the Ionic Mechanism of Soot Formation with a Free Radical Mechanism
The possible mechanisms by which large hydrocarbon ions might be produced in a fuel rich sooty flame are examined and all of them are eliminated except growth through ion-molecule reactions starting from the chemiion, HCO+. Large ions are not, as sometimes assumed, an indicator of neutral species. The ionic mechanism of soot nucleation is compared with a free radical mechanism by comparing the time each mechanism requires to add 10 carbon atoms to the growing species, ion or neutral. Experimental concentrations are combined with appropriate rate coefficients for the individual steps. The ionic mechanism appears to require less time, but the differences are within the accuracy of the data available.
KeywordsSoot Particle Neutral Species Soot Formation Ionic Mechanism Combustion Institute
Unable to display preview. Download preview PDF.
- 29.6D.B. Olson, H.F. Calcote: “Ions in fuel-rich and sooting acetylene and benzene flames” in Eighteenth Symposium (International) on Combustion ( The Combustion Institute, Pittsburgh 1981 ) p. 453Google Scholar
- 29.9S.E. Stein, S.A. Kafafi: “Thermochemistry of Soot Formation”, in Proceeding on Fall Technical Meeting, Eastern Section (The Combustion Institute, NBS 1987 )Google Scholar
- 29.11K.H. Homann: “Precursor Formation” in “Soot Formation in Combustion” -an International Round Table Diskussion, ed. by H. Jander, H.Gg. Wagner ( Vandenhoeck and Ruprecht, Göttingen 1990 ) p. 127Google Scholar
- 29.13P. Michaud, J.L. Delfau, A. Barassin: “The positive ion chemistry in the post-combustion zone of sooting premixed acetylene low pressure flat flames” in Eighteenth Symposium (International) on Combustion ( The Combustion Institute, Pittsburgh 1981 ) p. 443Google Scholar
- 29.14H.F. Calcote, R.J. Gill: in preparationGoogle Scholar
- 29.15H.F. Calcote: in Ion-Molecule Reactions, Vol. 2, ed. by J.L. Franklin ( Plenum Press, New York 1972 ) p. 673Google Scholar
- 29.16H.F. Calcote, R.J. Gill: “Computer Modeling of Soot Formation Comparing Free Radical and Ionic Mechanisms” AeroChem TP-495 (April 1991)Google Scholar
- 29.18C. Vovelle, personal communication (December 1989)Google Scholar
- 29.19J.D. Bittner, J.B. Howard: “Preparticle chemistry in soot formation” in Particulate Carbon: Formation During Combustion, ed. by D.G. Siegla, G.W. Smith (Plenum Press, New York 1981 ) p. 109Google Scholar
- 29.20M. Frenklach, H. Wang: “Detailed modeling of soot particle nucleation and growth” in Twenty-Third Symposium (International) on Combustion ( The Combustion Institute, Pittsburgh 1991 ) p. 1559Google Scholar