Nanoparticle formation and transformation in diesels: a multiscale computational tool

Abstract

The process of combustion is the dominant pathway through which mankind continuously injects particulate matter into the atmosphere at the present time.  These combustion-generated particles are present not only in a very large amount, but are produced, at the smallest scale, in the form of clusters with nanometric dimensions.  Although the total mass of particulate emissions has been significantly reduced with improvement of combustion efficiency and emissions control systems, the very small nanoparticles are exceedingly difficult to control by the emission systems typically installed on vehicles.  In addition, the current emissions regulations are mass-based and do not address the presence of nanoparticles. The objectives of this work are focused on gaining a clearer understanding of the chemical and physical processes occurring in the formation of carbon nanoparticles in combustion conditions.  The theoretical studies are directed at developing computational models that follow the chemical reactions, which are responsible for the formation of the heavier hydrocarbons and particle inception.  A major feature of these models is the identification of the chemical specificity of the soot precursor molecules and particles.  The carbonaceous particles are described using atomistic models, through a novel coupling of the Molecular Dynamics and Kinetic Monte Carlo methodologies to simulate the nanoparticle growth and through coarse-grained Molecular Dynamics to describe their agglomeration into larger primary soot particles.