Effect of water content of hydrous ethanol on chemical kinetic characteristics based on the new developed reduced ethanol-toluene reference fuels mechanism

• Published in: Fuel (Guildford) 2021-11, Vol.303, p.121201, Article 121201
• Main Authors: Shi, Xiuyong, Qian, Weiwei, Wang, Qiwei, Luo, Hengbo, Kang, Yang, Ni, Jimin
• Format: Article
• Language: English
• Subjects: Burning; Burning rate; Chemical kinetics; Chemical kinetics mechanism; Combustion; Decoupling method; Delay time; Engines; Ethanol; Ethanol-toluene reference fuels; Fuels; Gasoline; Heat release rate; Heat transfer; Ignition delay times; Laminar burning velocity; Moisture content; Octane number; Oxidation; Oxygen content; Reaction kinetics; Renewable energy; Spark ignition; Species mole fraction; Toluene; Velocity; Water content
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2021.121201

•A reduced chemical kinetic model is proposed for the oxidation mechanism of ethanol-gasoline blending fuels.•The simulated results have been verified with the experimental data under different conditions.•The water content effects on the combustion of ethanol has been analyzed. As a renewable energy, ethanol has attacked increasingly attention for spark-ignition engines due to its characteristics of high octane number and valuable oxygen content (34.74% v/v). However, little research expounds the fundamental of ethanol-gasoline blends in SI engines because of its complicated and changeable chemical kinetics mechanism. In this investigation, a reduced chemical kinetic model is proposed for the oxidation mechanism of ethanol-toluene reference fuels (TRF) blending fuels using the method of semi-decoupling methodology. The small molecule (H2 / CO / C1) mechanism is taken as the kernel in this model, and integrated the skeleton mechanism of ethanol into the TRF mechanism of gasoline surrogate as well, called E-TRF model, which contains 64 species and 194 elementary reactions. The simulated results of ignition delay times, laminar burning velocity, and in-cylinder pressure and heat release rate have been verified with the experimental data available in other literature under different operation conditions, respectively. The result shows that the E-TRF model could accurately predict the combustion characteristics of the ethanol-gasoline fuel. In addition, the water content effects on the combustion of ethanol has been also analyzed. It is found that an increase of water content leads to a decline of the critical radical production and burning temperature, which suppresses the combustion progress and eventually results in a decrease of laminar burning velocity. Moreover, the physical effect of water is more than 90% on laminar burning velocity and the physical effect of water at different temperatures is more than 80% on ignition delay times.