Time Evolution of the Aggregate Fractal Dimension from Langevin Dynamics

Combustion-generated solid nanoparticles are often fractal-like aggregates (clusters) of smaller units taken to be spherical primary particles, monomers. The aggregate mass exhibits a power-law dependence on a characteristic size, usually identified with the radius of gyration. The power-law exponent is the aggregate fractal dimension. We investigate the non-equilibrium Brownian particle dynamics by solving the Langevin equations for a system of interacting aggregates in three dimensions. Our objective is to study the time evolution of the aggregate fractal dimension as an indicator of the varying aggregate morphology.JRC.H.4-Transport and air qualit