摘要
为研究壁面温度和机油油膜对缸内直喷汽油(GDI)发动机喷雾撞壁后发展的影响,运用阴影法成像系统和相位多普勒激光测试系统(PDA)对喷雾撞壁后反弹高度、扩散距离以及特征点的粒径粒速做了试验研究.结果表明:壁温的升高或机油油膜的存在对喷雾撞壁后反弹和扩散起明显的促进作用.但是,当壁面达到莱顿弗罗斯特效应温度后,撞壁喷雾的反弹高度和扩散距离又开始减小.壁温的升高或机油油膜的存在,都会使喷雾轴线测点处法向速度向上的液滴比例增加,且喷雾边缘测点处液滴的切向平均速度明显增大.壁温的升高使喷雾撞壁后液滴的粒径分布向更小粒径的方向偏移,液滴粒径的算术平均值减小,但100,?m以上"超大液滴"的出现使轴线测点处液滴的索特平均直径增大.机油油膜的存在使喷雾撞壁后液滴粒径的算术平均值减小,但索特平均直径增大.
The aim of this experimental research is to studythe effects of wall temperature and oil film on the process of a gasoline spray after wall impingement. The research focuses on the spray rebound height,diffusion distance,droplet size and velocity distribution after wall impingement using shadow photographic method and phase Doppler analyzer（PDA）. The results show that the wall temperature or oil film plays a significant role in raising the spray rebound height and diffusion distance. But when the wall temperature is above the Leidenfrost temperature,the rebound height and diffusion distance begin to decrease. The normal and tangential velocities of droplet increases with the rise of wall temperature or the existence of oil film. As the wall temperature increases,the drop size distributionis towards smaller diameters and the average diameter of droplets decreases. Nonetheless,due to “huge droplet” whose diameter is bigger than 100,μm,the normal direction droplets’ Sauter mean diameter increases. The oil film has an influence on the droplet distribution,with the droplets’ average diameter decreasing while their Sauter mean diameter increasing.
出处
《天津大学学报（自然科学与工程技术版）》
EI
CSCD
北大核心
2016年第11期1195-1202,共8页
Journal of Tianjin University：Science and Technology
基金
国家科技支撑计划资助项目(2014BAG10B01)
关键词
缸内直喷汽油发动机
喷雾撞壁
壁面温度
机油油膜
gasoline direct injection（GDI）engine
spray impingement
wall temperature
oil film
