Document Type

Article

Research Focus Area

Catalysis and Reaction Engineering, Computational Fluid Dynamics, Health Care Technology and Biomedical Engineering

Publication Date

11-12-2010

Journal or Book Title

Physical Review E

Volume

82

Issue

5

First Page

051402

DOI

10.1103/PhysRevE.82.051402

Abstract

The diffusion of fractal aggregates constructed with the method by Thouy and Jullien [J. Phys. A 27, 2953 (1994)] comprised of Np spherical primary particles was studied as a function of the aggregate mass and fractal dimension using molecular dynamics simulations. It is shown that finite-size effects have a strong impact on the apparent value of the diffusion coefficient (D), but these can be corrected by carrying out simulations using different simulation box sizes. Specifically, the diffusion coefficient is inversely proportional to the length of a cubic simulation box, and the constant of proportionality appears to be independent of the aggregate mass and fractal dimension. Using this result, it is possible to compute infinite dilution diffusion coefficients (Do) for aggregates of arbitrary size and fractal dimension, and it was found that Do∝N−1/dfp, as is often assumed by investigators simulating Brownian aggregation of fractal aggregates. The ratio of hydrodynamic radius to radius of gyration is computed and shown to be independent of mass for aggregates of fixed fractal dimension, thus enabling an estimate of the diffusion coefficient for a fractal aggregate based on its radius of gyration.

Comments

This article is from Physical Review E 82 (2010): 051402, doi: 10.1103/PhysRevE.82.051402. Posted with permission.

Copyright Owner

The American Physical Society

Language

en

File Format

application-pdf

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