华南理工大学学报(自然科学版) ›› 2023, Vol. 51 ›› Issue (3): 33-40.doi: 10.12141/j.issn.1000-565X.220206

所属专题: 2023年能源、动力与电气工程

• 能源、动力与电气工程 • 上一篇    下一篇

多组分燃料液滴高温蒸发耦合机制研究

梅德清 俞玥 高亚平 祁佳炜 章传方   

  1. 江苏大学 汽车与交通工程学院,江苏 镇江 212013
  • 收稿日期:2022-04-14 出版日期:2023-03-25 发布日期:2022-09-01
  • 通信作者: 梅德清(1974-),男,博士,教授,主要从事发动机排放控制与新能源研究。 E-mail:meideqing@ujs.edu.cn
  • 作者简介:梅德清(1974-),男,博士,教授,主要从事发动机排放控制与新能源研究。
  • 基金资助:
    国家自然科学基金资助项目(51876082);江苏省国际合作项目(BZ2022016)

Coupling Mechanism of High-Temperature Evaporation of Multi-Component Fuel Droplets

MEI Deqing YU Yue GAO Yaping QI Jiawei ZHANG Chuanfang   

  1. School of Automotive and Traffic Engineering,Jiangsu University,Zhenjiang 212013,Jiangsu,China
  • Received:2022-04-14 Online:2023-03-25 Published:2022-09-01
  • Contact: 梅德清(1974-),男,博士,教授,主要从事发动机排放控制与新能源研究。 E-mail:meideqing@ujs.edu.cn
  • About author:梅德清(1974-),男,博士,教授,主要从事发动机排放控制与新能源研究。
  • Supported by:
    the National Natural Science Foundation of China(51876082);Jiangsu International Cooperation Project(BZ2022016)

摘要:

以高挥发性的乙醇与低挥发性的加氢生物柴油和柴油构成的多组分混合燃料为研究对象,研究了单个液滴在高温下的内部蒸汽气泡动力学及蒸发特性。在恒温加热炉中,采用挂滴法结合高速显微成像技术,在773、873和973 K温度下,捕捉了加氢生物柴油-乙醇-柴油混合燃料液滴在蒸发过程中的形态变化,分析了液滴的归一化平方直径和寿命等特征。研究表明,在773 K下,蒸发过程较平稳,液滴体积均匀减小,而在973 K下,0.093 s时液滴内开始产生微小气泡并逐渐增大;在0.767 s时再次形成微小气泡,并于0.907 s时出现第2次破裂。升高环境温度有助于增加燃料液滴的蒸发速率,加剧蒸发过程中的微爆现象,一定程度上缩短了液滴的蒸发时间;蒸发过程中液滴内部的气泡增长与汽液界面的Rayleigh-Taylor不稳定性有关,且在液滴表面观察到了表面张力现象;与柴油相比,随着二元燃料中加氢生物柴油含量的增加,组分对蒸发的抑制作用更强,与二元燃料相比,三元燃料中的乙醇促进了微爆,缩短了液滴蒸发;三元燃料的液滴蒸发按序呈现乙醇主导、乙醇和柴油共同主导以及三者共同蒸发3个典型特征阶段。

关键词: 三元燃料, 液滴, 蒸发, 微爆, 挂滴法

Abstract:

This study took a multi-component composed of high volatility ethanol and low volatility hydrogenated biodiesel and diesel as the research object and investigated the internal vapor bubble dynamics and evaporation characteristics of the individual droplet at high temperatures. The evaporation characteristics of droplet normalized square diameter and droplet lifetime of the blends of hydrogenated biodiesel, ethanol, and diesel were captured by means of the hanging droplet method and high-speed microscopic imaging in a constant temperature heating furnace. The results show that at 773 K, the evaporation is smooth and the droplet volume decreases uniformly. However, at 973 K, tiny bubbles start to form inside the droplet at 0.093 s and gradually increase in size. Tiny bubbles were formed again at 0.767 s and the second rupture occurs at 0.907 s. The rise in ambient temperature contributes to increasing the evaporation rate of fuel droplets and intensifies the micro explosion during evaporation and shortens the evaporation of droplets to a certain extent; the growth of bubbles inside the droplet during evaporation is related to the Rayleigh-Taylor instability at the vapor-liquid interface, and surface tension phenomenon is observed on the surface of droplets. Compared to diesel, the inhibition effect of evaporation is stronger with the increase of hydrogenated biodiesel in binary fuels and compared with binary fuels, ethanol in ternary fuels promotes micro explosions and shortens droplet evaporation. The droplet evaporation of the ternary fuel shows three typical characteristic stages in the order of ethanol domination, ethanol and diesel co-domination and co-evaporation of all three.

Key words: ternary fuel, droplet, evaporation, micro explosion, hanging drop method

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