A novel atom tracking algorithm for the analysis of complex chemical kinetic networks

A novel numerical algorithm is presented that enables the tracking of specific atoms during the simulation of simple combustion reactors as those atoms are transferred from initial reactants to final products. Tracking is performed by labeling individual atoms or groups of atoms of interest, and solving, in addition to the coupled ordinary differential equations describing the time evolution of species concentrations, appropriate transfer equations providing the concentration of tracked atoms at each possible location on all chemical species involved. The transfer equations for a given chemical kinetic mechanism are automatically generated using simple structural and energy-based arguments to characterize and quantify how, in each elementary reaction, atoms are re-organized as reactants are converted into products. The capabilities of the tracking algorithm are illustrated by analyzing soot precursors formation in a constant-volume homogeneous reactor, providing new, quantitative evidence of well-known behaviors, such as the link between the molecular structure of a fuel and its sooting propensity.