喷射压力对燃油喷雾和油气混合特性的影响  

Effects of injection pressure on fuel spray and air-fuel mixing process of diesel engine

作　　者：解方喜[1,2] 于泽洋[1] 刘思楠[1] 曹晓峰 贾贵起 洪伟[1] 

机构地区：[1]吉林大学汽车仿真与控制国家重点实验室,长春130022 [2]东风朝阳朝柴动力有限公司,辽宁朝阳122000

出　　处：《吉林大学学报（工学版）》2013年第6期1504-1509,共6页Journal of Jilin University:Engineering and Technology Edition

基　　金：国家自然科学基金项目(51206059)

摘　　要：针对一台高压共轨发动机,利用三维CFD软件Fire研究了其喷射压力对燃油喷雾特性、缸内油气混合及有害排放物形成过程的影响。研究结果表明:提高喷射压力可使喷雾体贯穿距离增大、油滴索特平均直径SMD显著减小、燃油雾化质量也得到改善。同时,喷射压力的增大也使燃油的扩散能力提高、分布体积增大、碳烟的氧化增强。整体上看,随喷射压力的提高,Soot的最终生成量降低,而NO排放量增加。然而,提高压力也会使得燃烧过程中、前期的燃油富集程度升高,油气混合更为恶化,使得当喷射压力提高到一定程度后其对Soot排放的影响敏感性降低。Numerical and experimental studies were carried out on a 2L HPCR diesel engine to explore the effects of fuel injection pressure on the processes of fuel spray, air-fuel mixing and the formation of harmful emission. Results show that, as the injection pressure increases, the spray penetration increases, the Sauter Mean Diameter （SMD） of fuel drips significantly decreases, and the atomization quality is improved. Furthermore, with the increase in injection pressure, the diffusion capability of fuel is improved, the distribution volume increases and the oxidation of soot is enhanced. On the whole, with the increase in fuel injection pressures, the soot emission is reduced and the NO emission is deteriorated. However, the increase in injection pressure can result in higher degree of fuel richness in early period of combustion and further deterioration of air-fuel mixing. When the injection pressure reaches a certain level, it can weak the sensibility of its influence on soot emission.

关 键 词：动力工程 柴油机 喷射压力 喷雾 油 气混合 数值模拟 

分 类 号：TK421[动力工程及工程热物理—动力机械及工程]