Modelling the internal structure of nascent soot particles
- Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge CB2 3RA (United Kingdom)
- Department of Chemistry, University Chemical Laboratories, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom)
- Department of Physics, Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom)
In this paper we present studies of clusters assembled from polycyclic aromatic hydrocarbon (PAH) molecules similar in size to small soot particles. The clusters studied were comprised of coronene (C{sub 24}H{sub 12}) or pyrene (C{sub 16}H{sub 10}) molecules and represent the types of soot precursor molecule typically found in flame environments. A stochastic 'basin-hopping' global optimisation scheme was used to locate low-lying local minima on the potential energy surface of the molecular clusters. TEM-style projections of the resulting geometries show similarities with those observed experimentally in TEM images of soot particles. The mass densities of these clusters have also been calculated and are lower than bulk values of the pure crystalline PAH structures. They are also significantly lower than the standard value of 1.8 g/cm{sup 3} used in our soot models. Consequently we have varied the mass density between 1.0 g/cm{sup 3} and 1.8 g/cm{sup 3} to examine the effects of varying soot density on our soot model and observed how the shape of the particle size distribution changes. Based on similarities between nascent soot particles and PAH clusters a more accurate soot density is likely to be significantly lower than 1.8 g/cm{sup 3}. As such, for modelling purposes, we recommend that the density of nascent soot should be taken to be the value obtained for our coronene cluster of 1.12 g/cm{sup 3}. (author)
- OSTI ID:
- 21305709
- Journal Information:
- Combustion and Flame, Vol. 157, Issue 5; Other Information: Elsevier Ltd. All rights reserved; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
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