[1]高永强,陶莉莉,刘永辉,等.针阀启闭过程近场射流破碎机理的研究[J].内燃机学报,2020,(05):409-416.[doi:10.16236/j.cnki.nrjxb.202005053]
 Gao Yongqiang,Tao Lili,Liu Yonghui,et al.Investigation on Fuel Jet Breaking Mechanism in Near-Nozzle Region During the Opening and Closing of the Needle[J].,2020,(05):409-416.[doi:10.16236/j.cnki.nrjxb.202005053]
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针阀启闭过程近场射流破碎机理的研究
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《内燃机学报》[ISSN:1006-6977/CN:61-1281/TN]

卷:
期数:
2020年05
页码:
409-416
栏目:
出版日期:
2020-09-25

文章信息/Info

Title:
Investigation on Fuel Jet Breaking Mechanism in Near-Nozzle Region During the Opening and Closing of the Needle
作者:
高永强陶莉莉刘永辉王希波常 静钟 兵
(山东交通学院 汽车工程学院,山东 济南 250357)
Author(s):
Gao YongqiangTao LiliLiu YonghuiWang XiboChang JingZhong Bing
(School of Automotive Engineering,Shandong Jiaotong University,Jinan 250357,China)
关键词:
初始射流结构针阀初始气泡射流破碎机理
Keywords:
initial fuel jet structureneedle valveinitial bubblebreakup mechanism of fuel jet
分类号:
TK470
DOI:
10.16236/j.cnki.nrjxb.202005053
文献标志码:
A
摘要:
设计搭建了喷油器试验平台,采用数码相机和高放大倍数、高分辩率的长距离显微镜成像技术,对燃油近场区域射流破碎进行可视化试验.并以试验工况下的流动为研究对象,基于开源计算流体动力学(CFD)软件OpenFOAM 对针阀启闭过程近场射流破碎进行了数值模拟.结果表明:喷油初期,针阀开启后燃油撞击喷孔内初始气泡造成近场初始射流不同破碎形态,初始气泡大小以及位置导致近场初始射流头部不同结构形态;射流表面形成不稳定的表面波以及表面波的增长导致了近场区射流初始破碎、射流与环境气体的交互作用,加速射流破碎以及液丝、液滴的形成,在射流表面液丝和液滴剥离处存在较强的微尺度湍流,该区域具有较高的湍动能和亚网格涡黏系数;喷油末期,随着针阀关闭射流逐渐收缩,最终形成较粗液丝状,并呈非轴对称摆动.
Abstract:
A visual test platform for the fuel injection atomization process was designed and built. With a nanosecond level flash lamp being as an exposure light source,the digital camera was combined with a high magnification,high-resolution and long-distance microscope to capture high resolution atomization images. Based on the open source computational fluid dynamics(CFD) software OpenFOAM,the fuel jet breaking in the near nozzle region was numerically simulated and the simulation results were coincided with the experimental results. The results show that the initial jet tip breakup in the near-nozzle region is caused by the initial bubble,which has an important impact on the next injection jet. The different size and position of the initial bubbles give different shape structure in the jet tip region during the opening of the needle. The initial breakup of the jet in the near-nozzle region is mainly caused by the effect of turbulence in the nozzle hole. The surface wave growth of the fuel jet leads to the jet breakup. The development of surface wave further strengthens the interaction between the jet and the ambient gas. The liquid filaments and droplets separated from the jet surface are mainly the result of the development of the surface wave of the jet,leading to higher turbulent kinetic energy and higher sub grid eddy viscosity coefficient. At the end of the fuel injection,the jet is shrunk with the closing of the needle valve. Eventually,it forms a thicker liquid filament and a non-axisymmetric oscillation.
更新日期/Last Update: 2020-09-25