Improvement on a skeletal chemical kinetic model of iso-octane for internal combustion engine by using a practical methodology

Abstract

A skeletal chemical kinetic model of iso-octane oxidation for internal combustion engine is constructed by using a practical methodology. The new skeletal model consists of 32 species and 111 reactions. Based on the skeletal model target, the methodology considers a combustion mechanism as two parts: a comprehensive part describing reaction processes involving small radicals and molecules as the ‘core’, and a skeletal one which, in coupling with the ‘core’, controls the ignition characteristics. In order to improve the performance of the existing skeletal model of iso-octane oxidation in various reactors, the new skeletal model focuses on the improvement in predicting laminar flame speed and important species evolution while maintaining the accurate ignition delay prediction of the original mechanism. The new iso-octane model has been validated against various experimental data including shock tube, jet-stirred reactor, flow reactor, laminar flame speed and HCCI engine over wide operating conditions. The results show very good agreements with the experimental data, indicating that the practical methodology and the new skeletal model are well promising for various reactors and engine applications incorporated with a multi-dimensional CFD model.