Physicochemical analysis and modeling of combustion processes of mixed fuels in a diesel engine

The article presents a comprehensive numerical mathematical modeling of the combustion processes of composite fuels in a diesel engine. The research focuses on a detailed thermodynamic and kinetic analysis of the combustion of both traditional diesel fuel and its blends with ethanol and oleic acid, representing vegetable oils. The calculation of key parameters was carried out under conditions of competitive chemical reactions for oxygen: changes in internal energy and entropy, reaction initiation temperature, and combustion rates. The modeling was performed considering the polytropic character of the process and the changing temperature. It is shown that the introduction of ethanol increases the overall combustion rate of the mixture compared to pure diesel fuel. At the same time, the addition of oleic acid leads to a non-linear decrease in the process rate, although the effect is partially compensated by the temperature rise in the combustion chamber. The obtained results are of practical value for optimizing the composition of composite fuels and adjusting the operating parameters of a diesel engine to improve its efficiency and environmental performance.
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