Study of Scavenging and Combustion Processes for Small Two-Stroke Aviation Heavy Fuel Direct Injection Engines

Abstract

Heavy-fuel aviation piston engines (HF-APEs) are widely used in general aviation and unmanned aerial vehicle (UAV) due to their safety and fuel economy. This paper describes a numerical and experimental study of scavenging and combustion processes on a 2-Stroke Direct Injected HF-APEs for light aircraft, with its cylinder specifically designed as cross scavenging. A 3-Dimentional transient model of in-cylinder flow and combustion process is established by the Forte platform, and the engine test system is set up. By comparing the simulation results to the experimental results, it showed that multi-ports cross scavenging can generate unbalanced aerodynamic torque in the cylinder. In the compression process, the swirl ratio (SR) gradually increases, and the peak SR reaches 15. Moreover, approximately 25% of exhaust residual gas in the cylinder is conducive to the fuel atomization and evaporation process in a high-altitude environment. When the injection timing is between −8 °CA and −16 °CA, the engine has the optimal power and economy performance at different altitudes. Finally, when the injection advance angle moves forward by 4 °CA, the maximum pressure increases by 2 MPa, with the rising rate decreasing gradually. The results have important significance for the development of the combustion system of small 2-Stroke Direct Injected HF-APEs.

Improvement of inert-gas distribution for fuel tanks with the objective of minimum bleed flowrate

“…, 2012) studied the effects of different NEA intake arrangements on the inerting time and oxygen volume concentration of multi-bay fuel tanks by using CFD software; Shao Lei et al. (Shao Lei et al. , 2023) analyzed the optimal distribution of NEA in multi-bay fuel tanks based on entropy-weighted TOPSIS theory and investigated the impact of evaluation indicators for the speed of oxygen concentration decrease and the uniformity of oxygen distribution on the optimal NEA distribution method.…”