Physics of puffing and microexplosion of emulsion fuel droplets
Physics of puffing and microexplosion of emulsion fuel droplets
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DOI：
10.1063/1.4897918
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发表时间：
2014-10
影响因子：
4.6
通讯作者：
J. Shinjo;J. Xia;L. Ganippa;A. Megaritis
中科院分区：
文献类型：
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作者：
J. Shinjo;J. Xia;L. Ganippa;A. Megaritis
采用高保真界面捕捉模拟方法研究了油包水型乳化液滴微爆/膨化的物理过程。改变分散相（水）子液滴的尺寸/位置和爆炸沸腾（气泡形成）的起始位置，液滴破碎过程已被很好地揭示。气泡生长导致母体油滴的局部和部分破裂，即，喘着气。水子液滴的尺寸和位置决定了后抽吸动力学。水的子液滴的沸腾表面是不稳定的，并进一步发展。最后，子油滴被沸腾的水蒸气包裹，并从母油滴中分离出来。当水分子小时，分离快，油滴破碎有限。当它是大的，最初位于朝着母液滴中心，液滴破碎是更广泛的。对于由多个独立气泡同时生长所引发的微爆炸，每一次爆炸最初都是局部的和独立的，但它们之间的相互作用发生在稍后阶段。由于多次爆炸之间的相互作用，破裂的程度可以更大。这些研究结果表明，控制微爆/膨化是可能的，在燃料喷雾，如果乳化燃料混合物和环境流动条件，如加热设计得当。目前的研究也给了我们一个洞察模型的膨化和微爆的乳液液滴和喷雾。
The physics of water-in-oil emulsion droplet microexplosion/puffing has been investigated using high-fidelity interface-capturing simulation. Varying the dispersed-phase (water) sub-droplet size/location and the initiation location of explosive boiling (bubble formation), the droplet breakup processes have been well revealed. The bubble growth leads to local and partial breakup of the parent oil droplet, i.e., puffing. The water sub-droplet size and location determine the after-puffing dynamics. The boiling surface of the water sub-droplet is unstable and evolves further. Finally, the sub-droplet is wrapped by boiled water vapor and detaches itself from the parent oil droplet. When the water sub-droplet is small, the detachment is quick, and the oil droplet breakup is limited. When it is large and initially located toward the parent droplet center, the droplet breakup is more extensive. For microexplosion triggered by the simultaneous growth of multiple separate bubbles, each explosion is local and independent initially, but their mutual interactions occur at a later stage. The degree of breakup can be larger due to interactions among multiple explosions. These findings suggest that controlling microexplosion/puffing is possible in a fuel spray, if the emulsion-fuel blend and the ambient flow conditions such as heating are properly designed. The current study also gives us an insight into modeling the puffing and microexplosion of emulsion droplets and sprays.