Effect of equivalence ratio on spark ignition combustion of an air-assisted direct injection heavy-fuel two-stroke engine

• Published in: Fuel (Guildford) 2022-04, Vol.313, p.122646, Article 122646
• Main Authors: Chen, Zheng, Liao, Bin, Yu, Yunzhen, Qin, Tao
• Format: Article
• Language: English
• Subjects: Air safety; Air-assisted injection; Aviation; Aviation kerosene; Combustion; Computational fluid dynamics; Computer applications; Diesel fuels; Engines; Equivalence ratio; Flame propagation; Fluid dynamics; Gasoline; Heavy-fuel direct injection two-stroke engine; Hydrodynamics; Injection; Kerosene; Knock; Mathematical models; Mixtures; Simulation; Spark ignition; Three dimensional models
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2021.122646

•A two-stroke aviation engine with air-assisted injection is studied.•Heavy-fuel direct injection spark ignition (DISI) combustion is analyzed.•Ignition timing and equivalence ratio are discussed.•Diesel is more prone to knock than aviation kerosene in SI combustion.•Better combustion performance can be obtained by using a rich mixture. In the small aviation field, the research of direct injection (DI) heavy-fuel two-stroke engines has attracted much attention. The safety and unity of aviation heavy-fuel (i.e., aviation kerosene and diesel) is better than those of gasoline, which is more suitable for small aviation engines. In this paper, the influence of air-assisted injection on the formation and combustion of aviation kerosene direct injection mixture is studied on an aviation heavy-fuel direct injection spark ignition (DISI) two-stroke engine. Firstly, the spray simulation model of three-dimensional air-assisted injector was established by Computational Fluid Dynamics (CFD) software. And the effectiveness of the spray model was verified by comparing the simulation results with the experimental data of constant volume bomb spray. The combustion system CFD model of the two-stroke engine was further established to study the heavy-fuel spark ignition combustion at different ignition timings and equivalence ratios. The results show that when the ignition advance angle is 30°CA BTDC, higher combustion pressure and faster flame propagation speed can be achieved without knock. Aviation kerosene is less prone to knock than diesel and can achieve better combustion performance under the condition of rich mixture.