Development of skeletal chemical mechanisms with coupled species sensitivity analysis method

In this paper, we propose a chemical kinetic mechanism reduction method based on coupled species sensitivity analysis (CSSA). Coupled species graph of uncertain species was calculated using the interaction coefficient in the directed relation graph (DRG) approach and listed first, whereas species having large interaction coefficients were regarded as one unit and removed in the sensitivity analysis process. The detailed mechanisms for ethylene with 111 species and 784 reactions, and for n-heptane with 561 species and 2539 reactions, under both low and high temperatures were tested using the proposed reduction method. Skeletal mechanisms were generated, comprising a 33-species mechanism for combustion of ethylene and a 79-species mechanism for n-heptane. Ignition delay times, laminar flame speeds, perfectly stirred reactor (PSR) modeling as well as species and temperature profiles, and brute-force sensitivity coefficients obtained using the skeletal mechanisms were in good agreement with those of the detailed mechanism. The results demonstrate that the CSSA reduction approach can achieve compact and accurate skeletal chemical mechanisms and is suitable for combustion modeling.