对置活塞二冲程柴油机双喷油器碰撞喷雾试验研究  

Experimental Study of Impingement Spray of Dual-fuel Injector of Opposed Piston Two-stroke Diesel Engine

作　　者：刘宇航 赵振峰[1] 张付军[1] 谢钊毅 鲁怡 崔华盛 

机构地区：[1]北京理工大学机械与车辆学院,北京100081 [2]广州汽车集团股份有限公司汽车工程研究院,广东广州511434

出　　处：《兵工学报》2017年第10期1881-1890,共10页Acta Armamentarii

基　　金：国家部委基础研究项目(B2220110005)

摘　　要：为了获得良好的混合气,保证燃烧室形状、喷雾特性及缸内气体流动之间有良好的匹配,针对对置活塞二冲程柴油机燃烧室的喷雾特性,使用纹影法结合图像处理技术分析了喷油器布置方案、喷射压力、定容弹弹体压力和喷油持续期对油束贯穿距离及喷雾空间扩散率的影响。研究结果表明:在喷射压力75 MPa、弹体压力2 MPa、喷油持续期1.5 ms的工况下,双喷油器布置方案与单喷油器布置方案相比,空间扩散率更高,更有利于燃油的雾化;喷射压力的提高有利于燃油在空间的扩散,但近壁区内分布的燃油会随着喷射压力的提高而增加,造成"湿壁"现象;弹体压力过小会使油雾在壁面附近形成浓混合气区域,过大的弹体压力又会使燃油更多集中在中心区域;随着喷油持续期的增加,油束贯穿距离和空间扩散率的增加越来越不明显。Due to the special combustion chamber shape and spray mode of opposed piston two-stroke diesel engine,the fuel injection sprays impinge at the center of combustion chamber. The good matching of combustion chamber shape,spray characteristics and in-cylinder gas flow should be assured to obtain desired gas mixture. For the spray characteristics of combustion chamber in opposed piston two-stroke diesel engine,the schlieren method is used to study the influences of fuel injector position,injection pressure,constant volume bomb pressure and injection duration on spray penetration and spray spatial diffusion rate. The results show that,compared with single injector,the dual-fuel injector has higher spatial diffusion rate and is more beneficial to the atomization of fuel in the case of 75 MPa injection pressure,2 MPa constant volume bomb pressure and 1. 5 ms injection duration. The increase in injection pressure is beneficial to the diffusion of fuel in space,but the fuel distributed in near-wall area would be increased. As a result,the emission will be worsen because of＂cylinder wall wetting＂. Low constant volume bomb pressure causes a rich mixture near the cylinder wall,while high back pressure makes the fuelconcentrate in the center of combustion chamber where the flow is weak. With the increase in injection duration,the increase in spray penetration and spatial diffusion rate becomes less noticeable.

关 键 词：动力机械工程 碰撞喷雾 纹影法 双喷油器 试验研究 

分 类 号：TK421.42[动力工程及工程热物理—动力机械及工程]