Technical Report 45, c4e-Preprint Series, Cambridge

Modes of Neck Growth in Nanoparticle Aggregates

ref: Technical Report 45, c4e-Preprint Series, Cambridge

Associated Theme: Nanoparticles

Abstract

In this work we investigate the effect of non-uniform surface growth on flame generated nanoparticle aggregates. Two models are considered for the change in shape of a two unit aggregate gaining mass through surface reactions in order to answer a question from [Balthasar & Frenklach, Proc. Combust. Inst. 30(2005), 1467]. The first model, taken from the literature, represents the primary particles, which comprise an aggregate, as uniformly expanding, overlapping spheres. A second, new model is introduced, in which all growth is concentrated on the formation of a frustum between the two primary particles and used to test the importance of the uniform growth assumption. The effects of both models are investigated for soot formation in laminar premixed flames and are shown to predict significant differences in particle shape for a number of systems. The comparison was performed by calculating the percentage increase in mass needed to return a newly formed two unit aggregate to different levels of sphericity for both models, and collecting values for this percentage from simulations of premixed laminar flames.

Material from this preprint has been published in: Combustion and Flame 152 (2), 272-275, (2008)

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