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Measurement of Visible and Near-Infrared Optical Properties of Soot Produced from Laminar Flames.


pdf icon Measurement of Visible and Near-Infrared Optical Properties of Soot Produced from Laminar Flames. (206 K)
Zhu, J.; Choi, M. Y.; Mulholland, G. W.; Manzello, S. L.; Gritzo, L. A.; Suo-Anttila, J.

Combustion Institute, Symposium (International) on Combustion, 29th. Volume 29. Part 2. Proceedings. July 21-26, 2002, Sapporo, Japan, Combustion Institute, Pittsburgh, PA, 2367-2374 pp, 2002.

Keywords:

soot; laminar flames; optical properties; smoke; extinction

Abstract:

This study describes the measurements of the dimensionless extinction constant, Ke, of soot in the visible and infrared spectrum using the NIST Large Agglomerate Optics Facility (LAOF). Soot was produced using a 11 mm i.d. laminar diffusion flames burner fueled with acetylene and ethene. Light extinction measurements were performed using light sources at 543.5 nm, 632.8 nm, 856 nm, 1314 nm, and 1565 nm. The mean values of present measurements of Ke range from 7.95 to 10.0. These measurements represent the first fuel-specific data available in the near-infrared spectrum. The measured Ke values for all wavelengths are significantly larger than values calculated using reported values of the refractive index. For soot from acetylene flames, the Ke values increased with wavelength, whereas for soot from ethene flames, the Ke values decreased slightly with wavelength. Transmission electron microscopy and optical microscopy analyses were used to analyze soot morphology and aerosol properties to estimate the influences of beam shielding and light scattering on the observed variations of Ke.