- Author
- Megaridis, C. M.
- Title
- Thermophoretic Sampling and Soot Aerosol Dynamics of an Ethene Diffusion Flame.
- Coporate
- Brown Univ., Providence, RI
- Sponsor
- National Bureau of Standards, Gaithersburg, MD
- Report
- NBS GCR 87-532, December 1987, 210 p.
- Distribution
- Available from National Technical Information Service
- Contract
- NB83-NADA4025 60NANB6D0643
- Keywords
- aerosols | diffusion flames | morphology | particle size | soot | soot formation
- Identifiers
- soot formation
- Abstract
- A detailed investigation of the sooting structure of an overventilated laminar axisymmetric ethene/air diffusion flame under atmospheric pressure is presented. A thermophoretic sampling technique using a variety of probes is employed to obtain data on the morphological character of soot particles collected from various locations of the flame. The morphological features of the particles examined by Transmission Electron Microscopy provide not only qualitative information on particle agglomeration, surface growth, and oxidation but also quantitative data on primary particle size as a function of flame coorinates. An increasing primary particle size with height above the burner mouth proved the dominance of surface growth reactions on the morphology of particles transported in the lower and intermediate protions of the flame. The primary particle size was found to decrease as the particles move to the upper regions of the flame probably because of oxidation. A theoretical model examining the aerosol dynamics when particle formation, coagulation, and surface growth are present is also discussed. The combined observations of the thermophoretic method and optical measurements by others led to the conclusion that the soot particles are formed locally low in the flame in regions of high temperature near the reaction zone.