Nampoothiri K N, Nath A, Satpathi N S, Sen A K
Fluid Systems Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, Tamilnadu 600036, India.
Department of Mechanical Engineering, Amrita School of Engineering, Amrita Vishwa Vidyapeetham, Chennai, Tamilnadu 601103, India.
Langmuir. 2023 Mar 21;39(11):3934-3941. doi: 10.1021/acs.langmuir.2c03208. Epub 2023 Mar 7.
Deicing has significant relevance in various applications such as transportation, energy production, and telecommunication. The use of surface acoustic waves (SAWs) is an attractive option for deicing as it offers several advantages such as localized heating, in situ control, low power, and system integration for highly efficient deicing. Here, we report an understanding of the dynamics of deicing of microlitre volume water droplets (1 to 30 μL) exposed to low power (0.3 W) SAW actuation using an interdigitated electrode on a piezoelectric (LiNbO) substrate. We study the time variation of the volume of liquid water from the onset of SAW actuation to complete deicing, which takes 2.5 to 35 s depending on the droplet volume. The deicing phenomenon is attributed to acoustothermal heating which is found to be greatly influenced by the loss of ice adhesion with the substrate and the acoustic streaming within the liquid water. Acoustothermal heating inside the droplet is characterized by the temperature distribution inside the droplet using infrared thermography, and acoustic streaming is observed using dye-based optical microscopy. A rapid enhancement in deicing is observed upon the detachment of ice from the substrate and the onset of acoustic streaming, marked by a sudden increase in the liquid water volume, droplet temperature, and heat transfer coefficient. The deicing time is found to increase linearly with droplet volume as observed from experiments and further verified using a theoretical model. Our study provides an improved understanding of the recently introduced SAW-based deicing technique that may open up the avenue for a suitable alternative to standard deicing protocols.
除冰在交通运输、能源生产和电信等各种应用中具有重要意义。表面声波（SAW）的应用是一种有吸引力的除冰选择，因为它具有诸如局部加热、原位控制、低功耗以及便于系统集成以实现高效除冰等优点。在此，我们报告了对使用压电（LiNbO）衬底上的叉指电极，在低功率（0.3 W）SAW驱动下微升体积水滴（1至30 μL）除冰动力学的理解。我们研究了从SAW驱动开始到完全除冰过程中液态水体积随时间的变化，这取决于水滴体积，耗时2.5至35秒。除冰现象归因于声热加热，发现其受冰与衬底附着力的损失以及液态水中声流的显著影响。利用红外热成像通过液滴内部的温度分布来表征液滴内部的声热加热，并使用基于染料的光学显微镜观察声流。在冰从衬底脱离和声流开始时，观察到除冰迅速增强，其标志是液态水体积、液滴温度和传热系数突然增加。从实验中观察到除冰时间随液滴体积线性增加，并通过理论模型进一步验证。我们的研究增进了对最近引入的基于SAW的除冰技术的理解，这可能为标准除冰方案开辟一条合适的替代途径。
