Workbench for the Reduction of Detailed Chemical Kinetic Mechanisms Based on Directed Relation Graph and Its Deduced Methods: Methodology and <i>n</i>‑Cetane as an Example

Reduction of detailed mechanisms of large hydrocarbons is of significant importance to multi-computational fluid dynamics (CFD) simulations, while the scale and accuracy of the reduced mechanism are closely related to the reduction method adopted. In this study, a workbench for systematic reduction of detailed mechanism was developed. It is operated on the MATLAB platform and integrated with CHEMKIN PRO software. In the scheme, a skeletal reduction module was first employed to identify and eliminate unimportant species and associate reactions, in which four different algorithms based on directed relation graph (DRG) and its deduced methods, including single DRG, single DRG with error propagation (DRGEP), two-stage DRG, and DRG with DRGEP were applied and compared to find the optimal solution for further reduction. Then a subsequent reaction sensitivity analysis module was implemented to eliminate less important reactions. The potential and feasibility of the proposed scheme were presented with an example of reduction of a recently proposed detailed <i>n</i>-cetane mechanism. In skeletal reduction, DRG with DRGEP was found to be the optimal one and was finally selected for skeletal reduction. Within 10% error tolerance, a comprehensive reduced mechanism consisting of 521 species and 1623 reactions was generated with ∼75% reduction of species and 80% reduction of reactions. The reduced mechanism was well validated against the detailed mechanism in the ignition delay time, temperature profiles, and important species concentrations in a zero-dimensional homogeneous batch reactor, the species evolution in a jet-stirred reactor, and the one-dimensional premixed laminar flame speeds over a wide range of pressures (10–40 bar), temperatures (680–1600 K), and equivalence ratios (0.5–1.5)