Compact aerosol aggregate model (CA2M): A fast tool to estimate the aerosol properties of fractal-like aggregates

Abstract

The structure of fractal-like aggregates is of increasing interest to a variety of fields extending from combustion soot formation to synthesis of engineered nanoparticles. Nanoparticle aggregates and agglomerates formed of solid primary particles have been extensively studied, along with their subsequent processing, using increasingly sophisticated modelling techniques over the last decade. However, there is still a need for the community to have a simple and versatile tool, able to run on a single processor, which can estimate aerosol properties and compare them to experimental results. Many aerosol studies have focused on measuring the properties related to particle mass and momentum transfer and exchange with their surroundings. Often, simplified theories are available to support the experimental results (e.g., charging or transport) but show discrepancies due to the omission of complex phenomena related to particle morphology. Thus, there is a trade-off when one wants to use computer simulations to generate and process nanoaggregates through realistic scenarios in a limited amount of time. The tool presented here provides an efficient and realistic means to estimate mass, volume, projected-area, surface-area, mobility diameter, aerodynamic diameter, and effective density. Critical features treated here include the overlap and polydispersity of primary particles composing the aggregate. Computer-generated micrographs are also available for Scanning Electron Microscopy and Transmission Electron Microscopy data comparison. The code – available on request – originally runs on MATLAB and is built such that users can adapt it and extend it for their own studies.