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Computational Study of the Absorption and Scattering Properties of Soot.


pdf icon Computational Study of the Absorption and Scattering Properties of Soot. (419 K)
Farias, T. L.; Carvalho, M. G.; Koylu, U. O.; Faeth, G. M.

Combustion Institute/Eastern States Section. Chemical and Physical Processes in Combustion. Technical Meeting, 1993. October 25-27, 1993, Princeton, NJ, 394-397 pp, 1993.

Sponsor:

National Institute of Standards and Technology, Gaithersburg, MD

Keywords:

combustion; soot; absorption; scattering coefficient; simulation; aggregates; soot aggregates

Abstract:

Soot is present within most nonpremixed hydrocarbon-fueled flames, which affects their structure, radiation and pollutant emission properties. Thus, the absorption and scattering properties of soot are of interest in order to estimate continuum radiation from soot and to interpret nonintrusive optical measurements of soot concentrations and structure. Soot optical properties are challenging, however, dut to the complexity of soot structure. For example, while soot consists of small primary particles that individually satisfy the small particle (Rayleigh) scattering approximation, these particles form branched aggregates that exhibit neither Rayleigh nor Mie scattering behavior. Nevertheless, a potentially useful approximate theory of soot optical properties (denoted RDG-FA theory in the following) has been developed recently, based on the Rayleigh-Debye-Gans (RDG) scattering approximation while assuming that soot aggregates are mass-fractal objects. Past theoretical and experimental evaluations of RDG-GA theory, however, have not been definitive due to computational and experimental limitations. Thus, the objective of the present investigation was to complete an additional theoretical evaluation of RDG-FA theory for soot, based on computations using more exact theory for populations of mass-fractal aggregates having prescribed properties.