Skeletal mechanism generation and analysis for n-heptane with CSP

We use a procedure based on the decomposition into fast and slow dynamical components offered by the Computational Singular Perturbation (CSP) method to generate automatically skeletal kinetic mechanisms for the simplification of the kinetics of n-heptane oxidation. The detailed mechanism of the n-heptane oxidation here considered has been proposed by Curran et al. and involves 561 species and 2538 reactions. After carrying out a critical assessment of important aspects of this procedure, we show that the comprehensive skeletal kinetic mechanisms so generated are able to reproduce the main features of n-heptane ignition at various initial pressures and temperatures and equivalence ratios. A by-product of the algorithm that generates the skeletal mechanisms is the identification of the network of important species and reactions at a given state of the kinetic system. The analysis of this network is carried out by resorting to a visual representation of the pathways at selected time instants of the ignition process. Visual inspection of the pathways enables the identification and comparison of the relevant kinetic processes as obtained at different ignition regimes. The graphs are generated by interfacing the model reduction procedure with the open-source package graphviz.