W/O emulsions are considered as a beneficial alternative to the use of fossil hydrocarbon fuels and not treated vegetable oils. The presence of a dispersed phase composed of water allows to reduce pollutant emissions and also increases combustion efficiency because of the so-called micro-explosion phenomenon. This micro-explosion has a strong stochastic behavior, and its realization depends on several parameters such as water droplet size distribution and motion during heating. This paper aims to provide a better understanding of the impact of the water droplet behavior on the atomization rate. PLIF technique is used to visualize and track the motion of the water droplets dispersed inside heated emulsion drops. Natural convection of the water droplets is observed, and its impact on coalescence and atomization rate is investigated. Emulsion with small size distributions and high droplet velocity tends to show a low or nonexistent micro-explosion rate, while coarse emulsions show an important coalescence rate, resulting in a high micro-explosion occurrence. Finally, a dimensionless indicator measuring dispersed-phase motion intensity is proposed.

中文翻译：

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内部对流是否会促进无乳液液滴的微爆炸？

W/O 乳液被认为是使用化石碳氢燃料和未经处理的植物油的有益替代品。由水组成的分散相的存在可以减少污染物排放，并且由于所谓的微爆炸现象而提高燃烧效率。这种微爆炸具有很强的随机行为，其实现取决于水滴尺寸分布和加热过程中的运动等几个参数。本文旨在更好地理解水滴行为对雾化率的影响。PLIF 技术用于可视化和跟踪分散在加热乳液滴内的水滴的运动。观察水滴的自然对流，并研究其对聚结和雾化率的影响。具有小粒径分布和高液滴速度的乳液往往表现出较低或不存在的微爆炸率，而粗乳液表现出重要的聚结率，导致较高的微爆炸发生率。最后，提出了一种测量分散相运动强度的无量纲指示器。