A skeletal mechanism for multi-component fuel combustion simulations

Abstract

The present study aims to develop a skeletal mechanism for multi-component fuel oxidation of diesel, biodiesel blended with short chain oxygenated fuels of ethanol and DMC. Starting from a detailed reaction mechanism, a reduced chemical kinetics which could treat both ethanol and DMC oxidation reactions was first developed using directed relation graph with error propagation and sensitivity analysis (DRGEPSA) method, and it was then combined with a tri-component biodiesel reaction mechanism developed in our previous study with CO, NOx and soot emission sub-models embedded. The final mechanism comprises 132 species and 617 elementary reactions. Extensive validations were performed for the developed skeletal mechanism through ignition delay testing and 3-D engine simulations. Validation results discerned that for ethanol, DMC and diesel fuels, predicted ignition delay time agreed very well with the detailed reaction mechanism or experimental results over a large range of initial pressure, temperature and equivalent ratio conditions with the maximum deviation below 25%, whereas for biodiesel, the largest discrepancy was 53%. 3-D engine combustion simulations also demonstrated that the ignition delay, cylinder pressure and heat release rate of diesel, biodiesel and their blend fuels with DMC could be very well reproduced by the present mechanism with reliable accuracies under various engine operating conditions.