AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Evaluating the Mobility of Soot Aggregates: Role of Electric Fields in Alignment
MINGDONG LI, George Mulholland, Michael Zachariah, University of Maryland
Abstract Number: 233 Working Group: Aerosol Physics
Abstract The mobility of a nonspherical particle is a function of both particle shape and orientation. In turn the higher magnitude of electric field causes nonspherical particles to align more along the field direction, thus increasing their mobility. In our previous works, we studied this effect on nanorods and doublets of spheres, and showed that the experimental measurements were in excellent agreement with our developed theory for the orientation-averaged mobility and the dynamic shape factor applicable to any axially symmetric particles in an electric field. In this work, we extend our study to fractal aggregates. The mobility of combustion generated soot was measured at various electric fields and compared with spherical lamp wick smoke particles. The measured mobility of these soot particles showed an effect of electric field induced alignment, which results in smaller mobility diameters (i.e. higher mobility) with higher electric fields, while the spherical lamp wick smoke demonstrated no such alignment effect. The alignment dependence of electric field of the soot aggregates showed roughly the same behavior as a spheroidal particle with aspect ratio between 1.2 and 1.3.