摘要
利用高速成像方法及激光光学诊断技术系统研究了不同边界条件下多孔直喷喷油器喷雾闪急沸腾特性,分析了环境压力、燃油温度、燃料成分及油束靶点布置等对汽油闪急沸腾的影响程度及范围,进一步明晰了喷雾发生闪急沸腾后空间形态的演变规律.结果表明:降低环境压力和提高燃油温度可促进喷雾闪急沸腾的发生,对于试验用汽油燃料,环境压力每降低0.04 MPa与燃油温度升高10℃对喷雾的闪急沸腾影响效果相当.冷态射流喷雾与剧烈闪急沸腾喷雾在空间形态上存在显著差异,剧烈闪急沸腾喷雾在初始阶段时油束便出现整体塌缩,空间形态由空心锥状逐渐演变为实心锥状结构.少量乙醇组分的掺入对冷态射流模式喷雾形态的影响不大,但在过热条件下会使混合燃料喷雾的整体形态向闪急沸腾程度更大的方向发展.通过提高喷油压力,可降低喷雾闪急沸腾贯穿距离对燃油温度的敏感度.
The effects of boundary conditions on flash-boiling characteristics in multi-hole injector of gasoline direct injection(GDI)engines were experimentally investigated with high-speed photography and laser fluorescent diagnostic technique.Tests were carried out in a constant volume combustion vessel in order to assure the precise atmosphere pressure and fuel temperature.Additionally,the effect of fuel injected and injection pressure on spray flash-boiling were evaluated experimentally,and then,the evolution process of the flash-boiling spray's spatial structure could be revealed.The results show that,both lower atmosphere pressure and higher fuel temperature could accelerate the flash-boiling process.There would be the same effect between the atmosphere pressure decreased by 0.04 MPa and the fuel temperature increased by 10℃.A significant difference could be found within cold jet spray and flash-boiling spray by using low proportional ethanol-gasoline blends,such as the spatial structure.The spray structure always turns from hollow cone into solid when the flash-boiling occurs.Smaller distinction on spray structure could be found for cold jet spray,but inversely,different things take place in superheated conditions.The flash-boiling spray penetration will be less sensitive to the fuel temperature when the injection pressure increases.
作者
吴坚
陈泓
杜家坤
李钰怀
占文锋
林思聪
Wu Jian;Chen Hong;Du Jiakun;Li Yuhuai;Zhan Wenfeng;Lin Sicong(GAC Automotive Research&Development Center,Guangzhou 511434,China)
出处
《内燃机学报》
EI
CAS
CSCD
北大核心
2019年第6期529-535,共7页
Transactions of Csice
基金
国家重点研发计划资助项目(2017YFB0103300)
关键词
直喷汽油机
定容燃烧弹
多孔喷油器
喷雾闪急沸腾
空间形态
激光诱导荧光
gasoline direct injection engine
constant volume combustion vessel
multi-hole injector
flashboiling spray
spatial structure
laser induce fluorescence(LIF)
