Numerical simulation on effects of spray angle in a swirl chamber combustion system of DI (direct injection) diesel engines

• Published in: Energy (Oxford) 2014-10, Vol.75, p.289-294
• Main Authors: Wei, Shengli, Ji, Kunpeng, Leng, Xianyin, Wang, Feihu, Liu, Xin
• Format: Article
• Language: English
• Subjects: Air pollution caused by fuel industries; Applied sciences; Chambers; Combustion; Combustion chambers; Combustion regulation; Combustion system; DI (direct injection) diesel engines; Diesel engines; Energy; Energy. Thermal use of fuels; Engines and turbines; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Homogeneity; Mathematical models; Numerical simulation; Pollution reduction; Spray angle; Sprayers; Sprays; Swirl chamber
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2014.07.076

In order to make better air utilization in combustion chamber to improve the mixture quality, enhance combustion efficiency and reduce emissions, a new swirl chamber combustion system of DI (direct injection) diesel engines is proposed. The in-cylinder spray, mixture formation and combustion progresses are simulated and investigated at different nozzle angles with AVL-FIRE code. Results show that in the current combustion system, spray angle of 146° is the best on the aspect of mixture homogeneity among all the cases. NO mass fraction is the lowest at spray angle of 154°, while Soot mass fraction is the lowest at spray angle of 146°. At the initial stage of spray, the fuel/air equivalence ratio distribution was primarily controlled by the squish and swirl, while after ignition in expansion stroke, the combustion swirl and reverse squish had great impact on the in-cylinder temperature distribution. To sum up, the spray angle and air motion matching with the combustion chamber is a key factor on combustion process and emissions performance. Considering the emission performance, spray angle of 150° is a relatively better compromise in the new combustion system. •A new swirl chamber combustion system of DI(direct injection) diesel engines is proposed.•The appropriate vortex motion can reduce the wall concentration of mixture.•The emissions of 150° spray angle is the best compromise.•Before spray, the turbulent kinetic energy is primarily controlled by the squish.•After spray, the combustion swirl and anti-squish have a great impact on TKE (turbulent kinetic energy).