汽车工程

汽车工程 ›› 2018, Vol. 40 ›› Issue (12): 1385-1392.doi: 10.19562/j.chinasae.qcgc.2018.012.002

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环境背压对多孔式喷油器雾化形态特征影响的数值解析*

赵洪雪1,2, 静大亮3, 丁海春2, 帅石金2, 庞昌乐4   

  1. 1.交通运输部公路科学研究院,北京 100088;
    2.清华大学,汽车安全与节能国家重点实验室,北京 100084;
    3.中国航空发动机研究院,北京 101300;
    4.中国农业大学工学院,北京 100083
  • 收稿日期:2017-11-21 出版日期:2018-12-25 发布日期:2018-12-25
  • 通讯作者: 帅石金,教授,博士,E-mail:sjshuai@tsinghua.edu.cn
  • 基金资助:
    国家自然科学基金重点项目(51636003)、国家重点研发计划(2016YFC0202700)和交通运输行业重点节能低碳技术推广目录(HBZ15080119-15)资助。

Numerical Investigation on the Effect of Ambient Pressure on the Morphological Characteristics of a Multi-Hole GDI Spray

Zhao Hongxue1,2, Jing Daliang3, Ding Haichun2, Shuai Shijin2, Pang Changle4   

  1. 1.Research Institute of Highway, Ministry of Transport, Beijing 100088;
    2.Tsinghua University,State Key Laboratory of Automotive Safety and Energy, Beijing 100084;
    3.Aero Engine Academy of China, Beijing 101300;
    4.College of Engineering, China Agricultural University, Beijing 100083
  • Received:2017-11-21 Online:2018-12-25 Published:2018-12-25

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摘要： 本文旨在通过数值模拟方法解析缸内直喷汽油机(GDI)多孔喷油器在不同环境背压条件下喷雾的形变特性及其影响机制。首先基于喷油器参数在Converge软件中建立了定容弹喷雾模型,进而根据高速摄影和相位多普勒粒子测试仪(PDPA)的试验结果对模型的喷雾宏观形态、贯穿距以及索特平均直径(SMD)进行了验证,在此基础上对0.1,0.5和1MPa环境背压条件下的喷雾形态变化进行了详细研究。研究结果表明:随着背压增加,油束被挤压并向喷油器中心轴线方向收缩,且贯穿距减小;由于油束对容弹内气流的冲击作用使得油束外边缘出现强烈的空气卷吸效应,致使在喷雾油束末端的液滴随气流向上回卷,且背压越高油束末端边界越不清晰;在喷雾压力场及速度场的分析中发现,由于喷雾内部区域压力低于外部,导致外部气流向内部冲击挤压油束,使得喷雾宽度减小,油束间相互作用增强,从而出现喷雾形变。

关键词: GDI喷雾, 环境背压, 喷雾形变, 三维数值模拟

Abstract: In this paper, the effect of ambient pressure on the morphological characteristics of a multi-hole gasoline direct injection (GDI) spray is simulated in CONVERGE. Firstly, a constant volume vessel spray model is established based on the injector parameters. According to the test results of high-speed imaging and phase doppler particle analyzer (PDPA), the Sauter Mean Diameter (SMD), spray morphology and penetration distance of the model is verified. Based on this, a detailed study on the spray morphological characteristics under 0.1,0.5 and 1MPa ambient pressure conditions is conducted. The results show that, the spray is compressed and contracted to the central axis of the injector and the penetration distance decreases under elevated ambient pressure. Due to the impact of the spray on the airflow in the vessel, a strong air entrainment effect is generated on the outer edge of the spray, resulting in rolling upward of the droplet at the end of the spray with the gas flow, and the higher the back pressure, the more indistinct the boundary of the spray end. After analysis of the spray pressure field and velocity field, it is found that pressure of the inner zone of the spray is lower than the outer zone, which causes the external airflow to impact the spray, thus reducing the spray width and enhancing the interaction, resulting in spray collapse

Key words: GDI spray, ambient pressure, spray collapse, 3D simulation