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.
Copyright Owner
The American Physical Society
Copyright Date
2010
Language
en
File Format
application-pdf
Recommended Citation
Pranami, Gaurav; Lamm, Monica H.; and Vigil, R. Dennis, "Molecular dynamics simulation of fractal aggregate diffusion" (2010). Chemical and Biological Engineering Publications. 92.
https://lib.dr.iastate.edu/cbe_pubs/92
Comments
This article is from Physical Review E 82 (2010): 051402, doi: 10.1103/PhysRevE.82.051402. Posted with permission.