Comparison of Biodiesel Performance Based on HCCI Engine Simulation Using Detailed Mechanism with On-the-fly Reduction

摘要

Biodiesel is a complex mixture of long-chain methyl esters. Accurate numerical study of biodiesel combustion requires detailed chemistry of large biodiesel surrogates representing realistic biodiesel fuels. However, the detailed kinetic mechanisms tor large biodiesel surrogales involve large number of species and reactions, leading to extremely expensive or even infeasfble computation when incorporated in engine CFD (computational fluid dynamics) calculations . In this study, the scheme of on-the-fly mechanism reduction incorporated with engine CFD code KTVA-3V is first extended to two large biodiesel surrogate mechanisms, namely methyl decanoate and methyl-9-decrnoate. Detailed combustion and engine performance characterization for biodiesel fuels are enabled, and the computational inensty is significantly reduced with satisfactory accuracy. In the simulations, lower CO and NO emissions and lower engine power an observed for biodiesel surrogates. Combustion features such as early oxidation of ester groups are also well captured. This work provides the insight to study combustion and engine operation of complex fuels on the basis of detailed chemistry with efficient mechanism reduction technique.