Investigation of the radiative properties of chain agglomerated soot formed in hydrocarbon diffusion flames
An investigation into the radiative scattering and extinction properties of chain-agglomerated soot particles, formed in hydrocarbon diffusion flames, has been conducted. Several different theoretical approximations of the agglomerate radiative behavior were examined. Based upon these approximations, the radiative properties of chain-agglomerates can show significant departure from those produced by spherically-shaped particles. For the visible and infrared wavelengths, a significant difference in the spectral variation of extinction cross section was noted between chain-agglomerates and spheres. The angular distribution of scattered radiation for the chain-agglomerate is, in addition, characteristic of scattering from a sphere having a diameter considerably larger than the characteristic dimension of the agglomerate. With respect to optical diagnostic methods for determination of soot particle size, the utilization of spherical-particle modeling in the inversion of extinction and scattering data can lead to both over- and under-prediction of particle size, depending upon the particular method used. Measurements of spectral extinction coefficient at five infrared wavelengths were performed in hydrocarbon/air, coflow diffusion flames, and the variation in wavelength of the measured extinction was examined. For certain flame conditions, the measured extinction spectra display an appreciable difference from those predicted for spherical particles having realistic diameters and refractive indices and indicate radiative behavior characteristic of elongated agglomerates. Differences in the apparent soot particle elongation were noted among the different fuels used in the investigation, which suggest that the fuel type may have more effect upon the physical structure of soot than previously believed.
- Research Organization:
- Kentucky Univ., Lexington, KY (USA)
- OSTI ID:
- 5535448
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
025000* -- Petroleum-- Combustion
AGGLOMERATION
CHEMICAL REACTION KINETICS
COMBUSTION KINETICS
COMPARATIVE EVALUATIONS
CONFIGURATION
DIFFUSION
ELECTROMAGNETIC RADIATION
ENERGY TRANSFER
FLAMES
HEAT TRANSFER
HYDROCARBONS
INFRARED RADIATION
KINETICS
ORGANIC COMPOUNDS
PARTICLE SIZE
PHYSICAL PROPERTIES
RADIANT HEAT TRANSFER
RADIATIONS
REACTION KINETICS
SCATTERING
SIZE
SOOT
SPHERICAL CONFIGURATION
THERMODYNAMIC PROPERTIES
VISIBLE RADIATION