Abstract Self-propelled droplet jumping phenomenon during condensation on superhydrophobic surfaces has various engineering applications such as heat transfer enhancement, hotspot cooling and anti-icing/frosting. Since most of the droplet jumping phenomena are induced by multi-droplet rather than two-droplet coalescence, understanding the influences of droplet number and multi-droplet location on the droplet jumping is essential. In this work, droplet jumping induced by multi-droplet coalescence was simulated using the volume of fluid (VOF) method with various coalesced droplet number and locations considered. The simulations showed visualized droplet morphology evolutions during the droplet jumping processes. The changes of several energies, such as surface energy, kinetic energy and jumping energy, were also discussed with the energy conversion efficiencies calculated. The results show that increasing the coalesced droplet number is advantageous for surface energy releasing and the energy conversion efficiency from the surface energy to the jumping energy also increases with increasing coalesced droplet number. Coalescence of droplets with more concentrated location distribution has weaker oscillation during the jumping process, along with less oscillatory kinetic energy, indicating that concentrated droplet distribution is conductive to increase the energy conversion efficiency from the surface energy to the jumping energy.

中文翻译：

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多液滴聚结引起的液滴跳跃能量分析：液滴数量和液滴位置的影响

摘要 超疏水表面凝结过程中的自推进液滴跳跃现象具有多种工程应用，如传热增强、热点冷却和防冰/结霜。由于大多数液滴跳跃现象是由多液滴而不是两液滴聚结引起的，因此了解液滴数量和多液滴位置对液滴跳跃的影响至关重要。在这项工作中，使用流体体积 (VOF) 方法模拟了由多液滴聚结引起的液滴跳跃，并考虑了各种聚结液滴数量和位置。模拟显示了在液滴跳跃过程中可视化的液滴形态演变。表面能、动能、跳跃能等多种能量的变化，还讨论了计算的能量转换效率。结果表明，增加聚结液滴数有利于表面能的释放，从表面能到跳跃能的能量转换效率也随着聚结液滴数的增加而增加。位置分布越集中的液滴聚结在跳跃过程中振荡越弱，振荡动能越小，表明液滴分布集中有利于提高从表面能到跳跃能的能量转换效率。结果表明，增加聚结液滴数有利于表面能的释放，从表面能到跳跃能的能量转换效率也随着聚结液滴数的增加而增加。位置分布越集中的液滴聚结在跳跃过程中振荡越弱，振荡动能越小，表明液滴分布集中有利于提高从表面能到跳跃能的能量转换效率。结果表明，增加聚结液滴数有利于表面能的释放，从表面能到跳跃能的能量转换效率也随着聚结液滴数的增加而增加。位置分布越集中的液滴聚结在跳跃过程中振荡越弱，振荡动能越小，表明液滴分布集中有利于提高从表面能到跳跃能的能量转换效率。