Development of a skeletal oxidation mechanism for biodiesel surrogate

Abstract

A new skeletal surrogate model including methyl decenoate (MD), methyl 5-decenoate (MD5D), and n-decane was proposed. In the surrogate model, MD and MD5D were chosen to respectively represent the saturated methyl ester and unsaturated methyl ester in biodiesel, and n-decane was included to match the energy content and C/H/O ratio of actual biodiesel fuel. Based on a decoupling methodology, an oxidation mechanism for the biodiesel surrogate was constructed by integrating the skeletal large-molecule sub-mechanisms for n-decane, MD and MD5D, a reduced C2–C3 mechanism, and a detailed H2/CO/C1 mechanism. The final mechanism for the biodiesel surrogate is composed of 60 species and 172 reactions. The mechanism was validated against experimental data, including ignition delay times in shock tubes and major species concentrations in jet-stirred reactors over wide operating conditions. Moreover, the mechanism was employed to simulate the combustion and emission characteristics of an engine operated in a low temperature combustion mode with SME as fuel. The overall agreement between the predictions and measurements is satisfactory.