高涡流条件下船用柴油机油气匹配研究
Research on Fuel-air Matching of Marine Diesel Engine under High Swirl Conditions
本研究针对低速二冲程船用柴油机，提出了缸内直接喷射新鲜空气 (IFA) 策略，在不影响扫气效率的基础上显著提升缸内涡流，通过CONVERGE数值模拟研究了其对缸内油气混合过程、燃烧及排放性能的影响。研究结果表明，IFA策略可有效提高缸内涡流，进而优化油气混合过程，改善燃烧性能。通过正交试验设计协同涡流面喷油角度、纵截面喷油角度两个关键喷油参数，获得最佳工况时热效率由Base工况的49.92%提升至51.97%。在高涡流及喷油参数优化的基础上，使用IFA策略满足Tier III排放标准需要更高的40%EGR率，此工况下NOx排放降低至2.82 g/kWh，相比Base工况BSFC降低了2.33 g/kWh。
In this study, the method named inject fresh air (IFA) technology is proposed in order to significantly improve the swirl ratio without affecting the scavenging efficiency. The effects on the fuel/air mixing process, combustion, and emission performance are studied by numerical simulation. The research results indicate that IFA technology can effectively increase the level of in-cylinder swirl by injecting fresh air directly into the cylinder, thereby optimizing the fuel/air mixing process and improving combustion performance. The two key fuel injection parameters, the injection angle of the cross section and the injection angle of the longitudinal section, were designed through orthogonal experiments. When the optimal working condition was obtained, the thermal efficiency increased from 49.92% of the Base case to 51.97%. Based on the optimization of high swirl ratio and fuel injection parameters, a higher EGR rate of 40% is needed to meet the requirements of Tier III emission regulations. Under this condition, NOx emission reduced to 2.82 g/kWh, and BSFC decreased by 2.33 g/kWh compared to the Base condition.
卢天龙;王天友;施磊;鲁祯;
天津大学能源与动力工程系,天津 300000;天津大学能源与动力工程系,天津 300000;天津大学能源与动力工程系,天津 300000;天津大学能源与动力工程系,天津 300000;
TK422
marine diesel engine inject fresh air high swirl ratio optimization of fuel injection parameters
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