Development of a combustion reaction kinetic model of heavy fuel oil for marine engine

Heavy fuel oil (HFO) is commonly used in the ocean transportation industry due to its low cost, which helps reduce transportation expenses. However, its composition is complex and contains many components with high carbon number, so it is difficult to construct reaction kinetics model. In order to develop a dynamic model of heavy fuel oil for practical computational fluid dynamics (CFD) simulation, this study proposed the idea of combining surrogate fuel and two-step reaction scheme (TSRS) to construct the kinetic mechanism of combustion reaction of heavy fuel oil. The five-component surrogate fuel containing 17.36% n-hexadecane, 9.89% naphthalene, 2.67% phenanthrene, 31.09% α-methylnaphthalene and 38.99% decalin was determined according to the chemical composition of heavy fuel oil, cetane number (CN), H/C ratio, density and lower heating value (LHV), and the actual physicochemical property error of HFO was kept within 5%. Combined with the two-step reaction scheme, a simplified kinetic mechanism was established for the high temperature combustion process of the surrogate fuel. The error between the prediction results of ignition delay time and concentration of important components and the experimental values is kept within 5%, which verifies the reliability of the surrogate fuel mechanism for predicting the base combustion process of heavy fuel oil. The error of heat release rate data of fuel ignitability analyzer (FIA) and cylinder pressure predicted value of two-stroke Marine engine and experimental data is within 10% and 2% respectively, which verifies the accuracy of the mechanism description of heavy fuel oil combustion process. In this study, the ignition and combustion characteristics of the fuel are reproduced by using the surrogate fuel with fewer components, and the kinetic mechanism containing fewer components and reactions is generated by the two-step reaction scheme method, indicating that the five-component surrogate fuel mechanism generated by the surrogate fuel method and the optimized two-step reaction scheme method can be used to construct the kinetic model of the combustion reaction of heavy fuel oil.