Self-affinity of combustion-generated aggregates
- Yale Univ., New Haven, CT (United States). Dept. of Chemical Engineering
A large population of combustion-generated soot aggregates (more than 3,000 samples) was thermophoretically extracted from a variety of laminar and turbulent flames and analyzed using transmission electron microscopy (TEM). It was shown that the scaling structural properties of these fractal aggregates cannot be exclusively characterized by a single mass fractal dimension. Asymmetric properties of the aggregates were considered here by first assuming and then demonstrating their self-affinity via. an affinity exponent reflecting scaling with respect to the length and width of the aggregate projections. In addition to the conventional fractal dimension, D{sub f}, determined by using the geometrical mean of the longitudinal and transverse sizes as the characteristic length, the affinity exponent, H, and two complementary fractal dimensions, one longitudinal, D{sub L} = [(1+H)/2]D{sub f}, and one transverse, D{sub W} = [(1+H)/2H]D{sub f}, were introduced. By fitting TEM data for the entire population of aggregates, the values D{sub f} = 1.75 and H = 0.91 were scaling is expected to lead to a better understanding of the transport properties and restructuring kinetics of flame-generated aggregates.
- OSTI ID:
- 248240
- Report Number(s):
- CONF-951155--; ISBN 1-55899-321-5
- Country of Publication:
- United States
- Language:
- English
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