Effects of aggregate morphology and size on laser-induced incandescence and scattering from black carbon (mature soot)
For this study, we have used a Single-Particle Soot Photometer (SP2) to measure time-resolved laser-induced incandescence (LII) and laser scatter from combustion-generated mature soot with a fractal dimension of 1.88 extracted from a burner. We have also made measurements on restructured mature-soot particles with a fractal dimension of 2.3–2.4. We reproduced the LII and laser-scatter temporal profiles with an energy- and mass-balance model, which accounted for heating of particles passed through a CW-laser beam over laser–particle interaction times of ~10 μs. The results demonstrate a strong influence of aggregate size and morphology on LII and scattering signals. Conductive cooling competes with absorptive heating on these time scales; the effects are reduced with increasing aggregate size and fractal dimension. These effects can lead to a significant delay in the onset of the LII signal and may explain an apparent low bias in the SP2 measurements for small particle sizes, particularly for fresh, mature soot. In addition, the results reveal significant perturbations to the measured scattering signal from LII interference and suggest rapid expansion of the aggregates during sublimation.
- Research Organization:
- Sandia National Lab. (SNL-CA), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division; USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- AC04-94AL85000
- OSTI ID:
- 1244114
- Alternate ID(s):
- OSTI ID: 1214605; OSTI ID: 1236242; OSTI ID: 1265197; OSTI ID: 1310312; OSTI ID: 1310313
- Report Number(s):
- SAND-2015-0193J; SAND2015-6102J; SAND-2015-6102J; S0021850215001020; PII: S0021850215001020
- Journal Information:
- Journal of Aerosol Science, Journal Name: Journal of Aerosol Science Vol. 88 Journal Issue: C; ISSN 0021-8502
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United Kingdom
- Language:
- English
Web of Science
Similar Records
Quantification of online removal of refractory black carbon using laser-induced incandescence in the single particle soot photometer
Soot-particle core-shell and fractal structures from small-angle X-ray scattering measurements in a flame