The formation and coagulation of soot aerosols generated by the pyrolysis of aromatic hydrocarbons

We report a study of the formation and growth of soot aerosols in incident shock flows of benzene, toluene, ethylbenzene and indene, highly diluted with argon at temperatures in the range 1600-2300 K at a total carbon concentration in the shock-heated gases of 2.0 x 1017 atoms/cm3. The extent of conversion of hydrocarbon into soot, i.e. the soot yield, during the shock flow was determined from extinction measurements at two different visible wavelengths, while the rate of growth of the soot particles was obtained from the variation in the intensity of Rayleigh scattering of a 1W argon-ion laser beam by the soot particles. Of particular interest is our finding that the soot yield some 2.5 ms after the onset of shock heating falls rapidly with increasing temperature from near 100% at 1750-1800 K to less than 5 % at 2300 K

[1]  I. Hurle,et al.  Shock-tube studies on the decomposition of tetramethyl-lead and the formation of lead oxide particles , 1972, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[2]  S. C. Graham.  The Refractive Indices of Isolated and of Aggregated Soot Particles , 1974 .

[3]  J. Visser.  On Hamaker constants: A comparison between Hamaker constants and Lifshitz-van der Waals constants , 1972 .

[4]  J. Howard.  On the mechanism of carbon formation in flames , 1969 .

[5]  G. D. Ulrich,et al.  Theory of Particle Formation and Growth in Oxide Synthesis Flames , 1971 .

[6]  L. Richards,et al.  Tinting strength of carbon black , 1972 .

[7]  D. B. Scully,et al.  Carbon formation from aromatic hydrocarbons II , 1965 .

[8]  R. P. Wilson,et al.  The combustion institute: Western States Section—1974 Spring Meeting , 1974 .

[9]  R. Long,et al.  Formation of polycyclic aromatics in rich premixed acetylene and ethylene flames , 1973 .

[10]  A. G. Gaydon,et al.  The shock tube in high-temperature chemical physics , 1963 .

[11]  S. C. Graham,et al.  Coagulation of molten lead aerosols , 1973 .

[12]  G. Hidy,et al.  Collision‐Rate Theory and the Coagulation of Free‐Molecule Aerosols , 1965 .

[13]  A. F. Sarofim,et al.  Optical Constants of Soot and Their Application to Heat-Flux Calculations , 1969 .

[14]  F. Beretta,et al.  Optical and chemical investigations on fuel-rich methane-oxygen premixed flames at atmospheric pressure , 1973 .

[15]  J. Howard,et al.  Physical mechanisms in carbon formation in flames , 1973 .

[16]  H. Wagner,et al.  Carbon formation in premixed flames , 1967 .

[17]  G. Cornetti,et al.  Formation of Polycyclic Aromatic Hydrocarbons in a Vertical Flow Reactor , 1972 .

[18]  F. S. Lai,et al.  The self-preserving particle size distribution for Brownian coagulation in the free-molecule regime , 1972 .

[19]  H. Wagner,et al.  Chemistry of carbon formation in flames , 1968, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.