Modelling soot formation in a premixed flame usingan aromatic-site soot model and an improvedoxidation rate

摘要

An updated rate of O2 oxidation of one to four ring polyaromatic hydrocarbons in premixed flames ispresented based on density function theory simulations of oxygen attack at different radical sites on variousPAHs. The rate is in agreement with other rates found in the literature; however, it is several orders of magnitudelower than the currently accepted oxidation rate of multi-ring aromatic species, including soot. Simulationsare presented of a premixed flame using this improved rate and a new advanced soot particlemodel, which is developed in this paper. This model includes unprecedented detail of the particles in theensemble, including the aromatic content, C/H composition and primary-particle aggregate structure.The O2 oxidation rate calculated in this paper is shown to give a better prediction of particle number densityand soot volume fraction for a premixed flame. The predicted particle size distributions are shown alsoto describe better the experimental data. Predicted C/H ratio and PAH size distributions are shown for theflame. Computed TEM-style images are compared to experimental TEM images, which show that theaggregate structure of the particles is well predicted.