Acoustic Waves for Active Reduction of Contact Time in Droplet Impact
Acoustic Waves for Active Reduction of Contact Time in Droplet Impact
复制标题
DOI：
10.1103/physrevapplied.14.024029
复制
发表时间：
2020-08-12
影响因子：
4.6
通讯作者：
Fu, YongQing
中科院分区：
文献类型：
--
作者：
Biroun, Mehdi H.;Li, Jie;Fu, YongQing
最小化液滴冲击接触时间对于自清洁、防腐蚀或防结冰等应用至关重要。最近的研究已经使用表面的纹理化来在冲击期间分裂液滴或诱导不对称扩散，但是这些需要特别设计的基底，其不能容易地重新配置。一个关键的挑战是实现液滴在光滑表面上的冲击期间的接触时间的有效减少，而没有纹理化，但具有主动和可编程控制。我们的实验结果表明，表面声波（SAW），在远离液滴的影响点的位置处产生的，可以用来最大限度地减少接触时间多达35%，而不需要纹理表面。此外，打开和关闭SAW的能力意味着可以以可编程的方式控制表面上的液滴冲击接触时间的减少。此外，我们的研究结果表明，通过施加声波，液滴在固体表面上的碰撞制度可以从沉积或部分反弹到完全反弹。为了研究液滴撞击的动力学，我们开发了多相流的数值模型并模拟了不同的液滴撞击场景。数值结果表明，声波可以用来修改和控制液滴内部的速度场。通过打破液滴内部再循环模式的对称性，在回缩过程中从界面能回收的动能增加，并且液滴可以以短得多的接触时间与表面完全分离。我们的工作开辟了机会，使用SAW器件，以尽量减少接触时间，改变液滴的影响制度，并计划或控制液滴的光滑或平面和曲面上的反弹，以及粗糙或纹理表面。
Minimizing droplet impact contact time is critical for applications such as self-cleaning, antierosion or anti-icing. Recent studies have used the texturing of surfaces to split droplets during impact or inducing asymmetric spreading, but these require specifically designed substrates that cannot be easily reconfigured. A key challenge is to realize an effective reduction in contact time during droplet impingement on a smooth surface without texturing but with active and programmable control. Our experimental results show that surface acoustic waves (SAWs), generated at a location distant from a point of droplet impact, can be used to minimize contact time by as much as 35% without requiring a textured surface. Additionally, the ability to switch on and off the SAWs means that a reduction in droplet impact contact time on a surface can be controlled in a programmable manner. Moreover, our results show that, by applying acoustic waves, the impact regime of the droplet on the solid surface can be changed from deposition or partial rebound to complete rebound. To study the dynamics of droplet impact, we develop a numerical model for multiphase flow and simulate different droplet impingement scenarios. Numerical results reveal that the acoustic waves can be used to modify and control the internal velocity fields inside the droplet. By breaking the symmetry of the internal recirculation patterns inside the droplet, the kinetic energy recovered from interfacial energy during the retraction process is increased, and the droplet can be fully separated from the surface with a much shorter contact time. Our work opens up opportunities to use SAW devices to minimize the contact time, change the droplet impact regime, and program or control the droplet's rebounding on smooth or planar and curved surfaces, as well as rough or textured surfaces.