喷油参数对汽油撞壁流动过程的影响  

Influence of fuel injection parameters on the flow process of gasoline‑wall interaction

作　　者：何邦全[1] 吴冠 HE Bangquan;WU Guan(State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学先进内燃动力全国重点实验室,天津300072

出　　处：《武汉大学学报（工学版）》2024年第8期1122-1130,共9页Engineering Journal of Wuhan University

基　　金：国家自然科学基金项目(编号:52076148)。

摘　　要：利用纹影法,在定容弹内研究了喷油压力、背压、撞壁距离对直喷汽油撞击活塞头部后喷雾特性的影响。结果表明,汽油撞壁后在撞壁点右侧形成一个逆时针旋转的涡流区,涡流的形成促进了浓稠区面积的减小。增加喷油压力、减小背压和撞壁距离可以减小相同喷油时刻下的浓稠区面积。喷油压力和背压对左侧扩散长度Sl影响很小,但Sl会随撞壁距离减小而明显缩短,当撞壁距离从18.1 mm减小至12.3 mm时,喷油结束后Sl的长度由20.9 mm缩短至16.3 mm。右扩散长度Sr随喷油压力的提高、背压的减小以及撞壁距离的缩短而增大,当背压小于0.5 MPa且撞壁距离大于18.1 mm时,喷雾有冲出活塞顶面的风险。撞壁后的喷雾扩散面积会随喷油压力的增加、背压减小或撞壁距离增大而增大。Using the schlieren method,the influence of fuel injection pressure,ambient pressure,collision distance in the constant volume chamber on spray characteristics after direct injection gasoline hit piston head were investigated.The results show that after the gasoline hits the piston,a counterclockwise rotating vortex area is formed on the right side of the collision point.The formation of vortex promotes the reduction of the area of the thickened zone.Increasing injection pressure,reducing ambient pressure and collision distance can reduce the area of the thickened zone at the same injection time.Fuel injection pressure and ambient pressure have little effect on the left diffusion length Sl,but Sl decreases significantly as the collision distance decreases.When the collision distance decreases from 18.1 mm to 12.3 mm,Sl reduces from 20.9 mm to 16.3 mm after injection.The right diffusion length Sr increases with the increase of fuel injection pressure,the decrease of ambient pressure and the shortening of the collision distance.When the ambient pressure is less than 0.5 MPa and the collision distance is greater than 18.1 mm,there is a risk that the spray may rush out of the top surface of the piston.The spray diffusion area increases with the increase of fuel injection pressure and the decrease of ambient pressure,and increases with the increase of collision distance.

关 键 词：汽油 喷雾 撞壁 

分 类 号：TK411[动力工程及工程热物理—动力机械及工程]