Morphology of Soot Collected in Microgravity Droplet Flames.
Morphology of Soot Collected in Microgravity Droplet
Manzello, S. L.; Choi, M. Y.
International Journal of Heat and Mass Transfer, Vol.
45, No. 5, 1109-1116, February 2002.
soot; microgravity; fractal properties; droplet
Measurements of the primary particle size, radius of
gyration, fractal dimension, and the mass fractal
prefactor were measured for soot sampled in n-heptane
droplet flames under microgravity conditions. These
represent the first such measurements obtained for
spherically symmetric droplet flames. Experiments were
performed in the NASA-Glenn Research Center in
Cleveland, OH. Soot was sampled at 0.2 and 0.5 s after
ignition for a 2.1 mm droplet burning in atmospheric
pressure air. The measured primary particle sizes were
significantly larger under microgravity conditions
compared to normal gravity and were found to increase
with residence time. The average radius of gyrations
were also larger for soot collected in microgravity
conditions. Differences in the particle and agglomerate
dimensions are believed to be caused by the longer
residence times. The fractal dimensions were found to be
nearly constant for all experiments while the prefactor
term was found to increase slightly with residence time.