喷孔长度和喷油体温度对乙醇柴油空化及近场喷雾的影响  

Effect of Orifice Lengths and Injector Temperatures on Cavitating Characteristics and Near-field Spraying Based on Ethanol-diesel

作　　者：高莹[1] 邓海鹏[1] 麻斌[1] 刘洪岐[1] 王亚娣[1] GAO Ying;DENG Hai-Peng;MA Bin;LIU Hong-Qi;WANG Ya-Di(State Key Laboratory of Automobile Simulation and Control,Jilin University,Changchun 130025,China)

机构地区：[1]吉林大学汽车仿真与控制国家重点试验室,长春130025

出　　处：《工程热物理学报》2020年第5期1261-1269,共9页Journal of Engineering Thermophysics

基　　金：国家科技支撑计划资助项目(No.2014BAG11B00)。

摘　　要：利用高速摄像机和放大比例的单孔透明喷嘴搭建可视化试验台,研究喷孔长度和喷油体温度对喷孔内乙醇柴油空化流动特性和近场喷雾的影响,试验用喷嘴的孔径均为2 mm,孔长分别为4 mm、6 mm和8 mm,喷油体温度分别控制在303 K、333 K和363 K。试验发现,随着孔内燃油平均流速的增加,各喷孔的空化现象依次经历了无空化、空化初生、空化发展和超空化5个阶段,短喷孔内更易发生空化现象,且在相同的空化阶段短喷孔的孔内燃油平均流速小于长喷孔;此外在相同进出口压差下短喷孔对应的近场喷雾锥角要大于长喷孔喷雾锥角。喷油体温度也会影响喷孔内空化流动特性和近场喷雾形态,喷油体温度越高,空化现象越强烈,空化变化速率越大;当喷孔进出口压差相同时,喷油体温度在303 K、333 K和363 K所对应的近场喷雾锥角依次增大。最大近场喷雾锥角所需的喷射压力随喷油体温度的升高而减小。A visible experimental test bench was set to explore the effect of orifice lengths and injector temperatures on cavitating characteristics and near-field spraying.The test bench was composed by a high-speed camera and a transparent single-orifice nozzle which was scaled up.The diameter of orifice was 2 mm,the testing lengths of orifice were 4 mm,6 mm and 8 mm,and the experimental temperatures of injector were well controlled under 303 K,333 K and 363 K respectively.Experimental result shows that:with the increase of mean velocity of ethanol-diesel fuel,five stages of cavitation(non-cavitation,incipence,development,super-cavitation and hydraulic flip)were observed in orifices.And cavitation was much easier to occur in short orifices.At the same stage,the mean velocity of ethanol-diesel fuel was lower in short orifices than in long orifices.Besides,the cone angle of near-field spray was bigger in short orifice,when pressure differences between inlet and outlet were the same.The temperature of injector also played a significant role to cavitation characteristics and morphology of near-field sprays.The phenomena of cavitation intensified and the pace of cavitating increased as a result of the temperature of injector rising up.The cone angle increased with the temperature of injector varied from 303 K to 333 K and to 363 K when the boundary pressure of the orifices were identical.And the injecting pressure for max cone angle of near-field spray decreased when injector temperature rose.

关 键 词：乙醇柴油 空化 近场喷雾 喷孔长度 喷油体温度 

分 类 号：TK417[动力工程及工程热物理—动力机械及工程]