高背压闪急沸腾条件下GDI喷油器喷雾特性的试验  

Experimental Investigation on Spray Characteristics of GDI Injector Under High Ambient-Pressure Flash-Boiling Condition

作　　者：战超 唐志涛[1] 张景宇 李雁飞[2] 帅石金[2] Zhan Chao;Tang Zhitao;Zhang Jingyu;Li Yanfei;Shuai Shijin(School of Mechatronics and Automobile Engineering,Yantai University,Yantai 264005,China;State Key Laboratory of Automotive Safety and Energy,Tsinghua University,Beijing 100084,China)

机构地区：[1]烟台大学机电汽车工程学院,山东烟台264005 [2]清华大学汽车安全与节能国家重点实验室,北京100084

出　　处：《内燃机学报》2020年第6期490-496,共7页Transactions of Csice

基　　金：国家重点研发计划资助项目(2018YFB0106000).

摘　　要：在定容燃烧弹内利用高速摄影技术研究了5孔喷油器在不同油温和背压条件下的喷雾特性,采用的燃料为正己烷,燃料温度范围为130~220℃,背压范围为0.08~0.90 MPa.结果表明:在低于大气压环境下,正己烷喷雾的各油束向喷油器的轴线位置偏移,聚拢成一个油束,喷雾发生坍塌;而在高背压闪急沸腾条件下观察正己烷的喷雾形态,可以看到单独油束,喷雾坍塌减弱,并且随油温的增加喷雾宽度逐渐变宽,这是由于高背压闪急沸腾环境下产生的大量蒸气抵消了高速射流运动引起的低压区,同时也进一步证实了高速射流运动引起的低压区不能完全解释低背压闪急沸腾环境下的喷雾坍塌.在背压为0.10~0.30 MPa下存在一个背压阈值,当背压低于阈值时,喷雾宽度随背压的增加而减小;而背压高于阈值时,喷雾宽度随背压的增加呈增长趋势.The spray characteristics of a five-hole direct injector under high ambient-pressure flash-boiling conditions were studied in a constant volume combustion vessel by means of high speed imaging measurement.n-hexane was used as the test fuel with temperature from 130℃to 220℃and ambient-pressure from 0.08 MPa to 0.90 MPa.The results show that,at the sub-atmospheric pressures,the individual jets move towards the axis of the injector and merge into one single jet,causing the spray collapse.In contrast,under elevated ambient-pressure flashboiling conditions,the jets are separated from each other and the spray collapse is mitigated.The spray width gradually widens with the increase of fuel temperature and this could be attributed to the massive production of vapor via surface boiling and the counteraction of the low-pressure tendency induced by the high-speed jets.It is further confirmed that the low-pressure area caused by the high-speed jet could not fully explain the spray collapse in the low ambient-pressure flash-boiling environment.Additionally,it is found that there should be an ambientpressure threshold between 0.1MPa and 0.3MPa.Below the threshold value,the spray width decreases with the increase of ambient-pressure.However,beyond the threshold value,an opposite trend is observed.

关 键 词：汽油缸内直喷喷油器 高背压 闪急沸腾 喷雾坍塌 

分 类 号：TK413.8[动力工程及工程热物理—动力机械及工程]