Development of a four-component reduced mechanism for the replacement of heavy fuel oil: n-hexadecane, n-tetradecane, toluene, 1-methylnaphthalene

Abstract

Heavy fuel oil (HFO) is the primary fuel used in marine transport. However, the development of a chemical reaction mechanism of HFO combustion in marine engines is relatively slow. To address the limitations of existing mechanisms, enhance simulation capability, and promote the optimization of marine engine design, this study developed a practical surrogate model and its corresponding reduced chemical reaction mechanism. In this study, n-hexadecane, n-tetradecane, toluene and 1-methylnaphthalene were used to represent HFO and a reduced chemical reaction mechanism was developed. Firstly, the composition of the surrogate fuel was determined by the chemical composition of HFO. Secondly, the surrogate fuel was optimized by adjusting the cetane number, low heating value, density at 20 °C and hydrogen/carbon ratio. Thirdly, based on the multi-level mechanism simplification strategy and the mechanism of 'decoupling method' simplification, a reduced HFO mechanism was constructed with 108 species and 360 reactions. Finally, the four components in the mechanism were verified by the ignition delay time of the shock tube and the component concentration of the jet stirrer reactor. In addition, the experimental data of HFO combustion in a two-stroke low speed marine diesel engine were also used to further evaluate the developed mechanism. The results show that the mechanism has good stability and reliability and can be applied to simulate HFO combustion under marine engine combustion conditions.