Chemical kinetic mechanism for diesel/biodiesel/ethanol surrogates using n-decane/methyl-decanoate/ethanol blends

Abstract

Diesel–biodiesel–ethanol blends have been the focus of research in engines, as biodiesel and ethanol additives can lower pollutant emissions while maintaining diesel performance. To facilitate modeling and analysis, those complex fuels are often substituted by simplified surrogate fuels, composed of only a few well-characterized molecules, but displaying similar properties compared to the fuel that they represent. In this context, the objective of this paper is to develop and validate a new chemical reaction mechanism for diesel–biodiesel–ethanol surrogate fuels. n-Decane and methyl-decanoate (MD) were chosen as the diesel and biodiesel surrogates, respectively, as they are frequently used in the literature. As the available reduced methyl-decanoate models do not reproduce the negative temperature coefficient behavior found in auto-ignition delay experiments, the detailed MD model of Dievart et al. was reduced using DRGEP. This last model was then combined with the reduced n-decane model due to Chang et al. and that of ethanol due to Marinov. Validations are performed on 0D constant-volume auto-ignition by comparing auto-ignition delay times and 1D freely propagating gaseous premixed flame configurations by analyzing laminar flame speeds, using the original single component kinetic models, against the combined surrogate kinetic models, and experimental results found in the literature. Laminar flame speeds of n-decane/methyl-decanoate/ethanol blends are also presented.