硅油-水复合液滴气动破碎实验研究

EXPERIMENTAL STUDY ON AERODYNAMIC BREAKUP OF SILICONE OIL-WATER COMPOSITE DROPLETS

  • 摘要: 在燃料领域,复合液滴的应用可以提高燃烧效率。针对复合液滴在气动力作用下的破碎机理,通过同轴射流方法制备硅油-水复合液滴,采用连续射流法和高速摄像技术拍摄进行探究。液滴在初始变形时期出现一种液滴形状--横飞碟状液滴,复合液滴达到这一状态所需要的时间随着韦伯数(We)的增加而减少,并进一步影响横飞碟的最大直径和变形时间。通过内外液体形态特征将实验中复合液滴的破碎划分为6种模态。气动破碎过程中外层的硅油在破碎时会带走相当大一部分能量,这导致内部水滴的破碎有明显的延迟,形成先外壳后内部的破碎顺序。还探究了We和粘度对其外壳剥离破碎的影响。

     

    Abstract: In the field of fuel applications, the use of compound droplets can enhance combustion efficiency. To investigate the breakup mechanism of compound droplets under aerodynamic forces, silicone oil-water compound droplets were prepared using a coaxial jet method, and their behavior was studied through continuous jet flow and high-speed imaging techniques. During the initial deformation stage, a distinctive droplet shape, known as a “horizontally flying disc,” was observed. The time required for the compound droplet to reach this state decreased with increasing Weber number (We), which also influenced the maximum diameter and deformation time of the disc. Based on the morphological characteristics of the inner and outer liquids, the breakup of compound droplets in the experiment was classified into six distinct modes. During the aerodynamic breakup, the outer silicone oil layer carried away a substantial amount of energy during its breakup, resulting in a significant delay in the breakup of the inner water droplet, establishing a sequence where the outer shell breaks first, followed by the inner liquid. Additionally, the effects of We and viscosity on the shell stripping and breakup process were further explored.

     

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