AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Effect of Fractal Morphology on Aggregates Mass Mobility Relationship
Pai Liu, RAJAN CHAKRABARTY, Washington University in St Louis
Abstract Number: 380 Working Group: Aerosol Physics
Abstract Past studies have shown that the diffusion limited cluster aggregation (DLCA) mechanism yields clusters with a fractal dimension of around 1.8 and prefactors ranging between 1.2 and 2.5. For a fixed cluster mass, an increasing prefactor physically manifests as a decrease in anisotropy or “stringiness” of the particle morphology. In this talk, we explore the effects of changing fractal prefactor and monomer diameter on DLCA aggregate mass-mobility relationship. Our simulation results showed that the mass-mobility exponent of a statistically significant number of aggregates with a fixed fractal dimension = 1.8 was around 2.2. This is in good agreement with previous experimental observations. The mass-mobility prefactor, on the other hand, was shown to be sensitive to variations in monomer size and fractal prefactor. The correctness of the empirical exponent 1.08, used for estimating number of monomers in 3 dimensions (3D) from 2 dimensional projection images, was also evaluated. It was found that the exponent was only valid for aggregates with a fractal prefactor = 1.3. With increasing fractal prefactor, use of the 1.08 exponent caused underestimation of monomer number in 3D.