Accession Number : AD0744920

Title :   Physical Mechanisms of Carbon Formation in Flames.

Descriptive Note : Technical rept.,

Corporate Author : PURDUE UNIV LAFAYETTE IND PROJECT SQUID HEADQUARTERS

Personal Author(s) : Wersborg,B. L. ; Howard,J. B. ; Williams,G. C.

Report Date : JUN 1972

Pagination or Media Count : 34

Abstract : The size, size distribution, number concentration, and number charged of carbon particles down to about 15 A diameter in a flat acetylene-oxygen flame at 20 mm Hg were measured using a molecular beam sampling system combined with electrical deflection of the beam and electron microscope analysis of beam deposits. Coagulation of carbon particles occurs at all positions sampled in the flame. This process and surface growth form particle clusters that gradually change from roughly spherical at early and intermediate stages of growth to chainlike in the flame tail. The particle size distribution changes from Gaussian in the early stages of carbon formation to lognormal in the later stages. Particle number concentration and the rate of nucleation and coagulation each exhibit a maximum soon after the onset of carbon formation, but the rate of surface growth is maximum initially. The number fraction of charged particles is 10 to 40%. (Author)

Descriptors :   (*CARBON, *COMBUSTION DEPOSITS), FLAMES, COMBUSTION PRODUCTS, PARTICLE SIZE, DEPOSITS, NUCLEATION, COAGULATION, REACTION KINETICS, CHARGED PARTICLES, ELECTRON MICROSCOPY

Subject Categories : Combustion and Ignition

Distribution Statement : APPROVED FOR PUBLIC RELEASE