Cai, G.Abraham, J.2014-04-112014-04-112013Proceedings of the Australian Combustion Symposium, Perth, WA, 6-8 November 2013 / Mingming Zhu, Yu Ma, Yun Yu, Hari Vuthaluru, Zhezi Zhang and Dongke Zhang (eds.): pp.206-209http://hdl.handle.net/2440/82486In this study, simulations are employed to improve the fundamental understanding of soot formation from a chemical kinetics perspective during biodiesel and petrodiesel combustion under pressure and temperature conditions in engines. n-Heptane is used as the surrogate for petrodiesel and a ternary mixture of methyl decanoate, methyl-9-decenoate, and n-heptane as the surrogate for biodiesel. In the case of the ternary biodiesel surrogate, a 211-species reduced mechanism is employed to model the chemical kinetics. This mechanism was derived as part of this work by combining reactions from the 160-species n-heptane mechanism with reactions from a skeletal 115-species mechanism proposed in the literature. Soot kinetics is represented using a chemical mechanism that models the growth of soot precursors starting from a single aromatic ring by hydrogen abstraction and carbon (acetylene) addition. The influence of turbulence is indirectly modelled through an imposed strain rate in the simulations. The computations are carried out using a strained laminar flamelet code (SLFC). Analysis of the results shows that the significant reduction in soot observed in biodiesel combustion results from an increase in the concentration of alkoxy species during the fuel breakdown process which, in turn, reduces the concentration of the aromatic species and the increased oxidation of the precursors that lead to the formation of the aromatic ring.en© the authorsBiodiesel combustionSoot formationReaction pathway analysisStrained flameletsConference paper002013602715838D2015/308856