A fundamental study of soot formation in diffusion flames
The isolated effects of fuel dilution and flame temperature variation on soot formation have been investigated experimentally for counterflow and coflow diffusion flames. The methodology of isolation through temperature adjustment involves changing the concentration of the fuel by diluting it with nitrogen, and then increasing the maximum temperature of the diluted flame back to that of the undiluted flame by replacing a portion of the nitrogen in the oxidizer flow with an equal portion of argon. Soot quantities are determined by using light-scattering and extinction techniques. In addition, smoke point measurements are made for the coflow flames. Results for ethylene show that both temperature and dilution contribute to a reduction in the soot volume fraction and dilution accounts for a substantial amount of this reduction. The above results imply that the effect of concentration is felt primarily in the particle-inception region. To further investigate this, measurements of the sooting limits were made in an opposed-jet counterflow flame. A numerical as well as experimentally investigation has been conducted on the influence of the mobility of inert additives on soot formation in propane and ethylene counterflow diffusion flames. The inerts used were helium, neon, argon, or krypton. Results show that while the mobility of the inert has practically no effect when a small amount is added to the oxidizer side, the influence is significant when added to the fuel side in that krypton, being the least mobile inert, yields the greatest soot loading while helium, being the most mobile, yields the least. An analysis has been performed to determine the applicability of the boundary layer flame codes, like that used above, for modeling a flame established in the stagnation region of a porous cylinder.
- Research Organization:
- California Univ., Davis, CA (USA)
- OSTI ID:
- 6893676
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
025000* -- Petroleum-- Combustion
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800 -- Combustion
Pyrolysis
& High-Temperature Chemistry
ADDITIVES
ALKANES
ALKENES
ARGON
BOUNDARY LAYERS
CHEMICAL REACTION KINETICS
COMBUSTION KINETICS
COUNTERFLOW SYSTEMS
DIFFUSION
ELEMENTS
ETHYLENE
FLAMES
FLUIDS
GASES
HELIUM
HYDROCARBONS
KINETICS
KRYPTON
LAYERS
LIGHT SCATTERING
MATHEMATICAL MODELS
MEASURING METHODS
NEON
NITROGEN
NONMETALS
ORGANIC COMPOUNDS
PROPANE
QUANTITY RATIO
RARE GASES
REACTION KINETICS
REYNOLDS NUMBER
SCATTERING
SOOT
SYNTHESIS
TEMPERATURE DISTRIBUTION