Simulation of Fuel Spray and Combustion of Compression Ignition Heavy-oil Engine

摘要

Compression ignition heavy-oil engines can be the alternative power for unmanned aerial vehicles (UAVs) and general aviation. In the future, stricter laws and regulations on the emission of aeroengines will be certainly carried out with the wide use of compression-ignition heavy-oil piston engines on general aviation and unmanned aerial vehicles. It is important to take emission into account besides dynamic performance and economy in the development of compression-ignition heavy-oil engines. In this study, a 3D numerical model is established to simulate the working process of a newly designed diesel engine to calibrate three important parameters including injection pressure, advanced injection angle, and nozzle diameter. The results show that injection pressure and advanced injection angle has a great effect on the dynamic performance of engines, such as vibration and noise. The NO emission is sensitive to injection pressure and advanced injection angle, while the Soot emission is sensitive to injection pressure and nozzle diameter. In addition, the study indicates that the combustion is coupled with the complex air flow in cylinder. With an appropriate match of intake vortex intensity, shape of combustion chamber, and injection pressure, the air flow in cylinder can be utilized to promote the mixing of fuel and air, and organize the combustion more efficiently.