Abstract:

The transportation characteristics of droplets on the horizontal aluminum surface under ultrasonic excitation are experimentally studied. In this study, the effects of ultrasonic power, initial droplet volume, and hydrophobicity on the movement process of droplets are explored. The research results indicate that the motion coalescence time and evaporation time of droplets are negatively correlated with ultrasonic power, but positively correlated with initial droplet volume and surface contact angle. With the increase of ultrasonic power, the particle size distribution uniformity of droplets increases, and the minimum motion coalescence time is 12 s, and the evaporation time can be shortened by 46 s at most. With the increase of the initial droplet volume, the particle size distribution uniformity of droplets weakens but the motion coalescence phenomenon increases. The hydrophobic surface can not only optimize the particle size distribution of droplets, but also enhance the motion coalescence process. Compared with the bare aluminum surface, the motion coalescence time of droplets on hydrophobic surface increases by about 17 s, and the evaporation time of droplets on hydrophobic surface can be extended by 62 s. This study confirms that ultrasound is feasible to inhibit frost formation.

Key words: ultrasound, droplets, hydrophobicity, coalescence, evaporation, surface

摘要：

实验研究了超声波激励下水平铝板表面液滴群的输运特性，探究了超声功率、初始液滴体积和疏水性对液滴群运动过程的影响。结果表明，液滴群运动聚结及蒸发时间均与超声功率呈负相关，而与初始液滴体积及表面接触角呈正相关。随着超声功率的增大，液滴群粒径分布更均匀，最小运动聚结时间为12 s，同时蒸发时间最多可缩短46 s。随着初始液滴体积的增大，液滴群粒径分布均匀性减弱但聚结现象增强。疏水表面不仅能优化液滴群粒径分布，还能增强运动聚结过程。与裸铝表面相比，疏水表面上液滴群运动聚结时间增加17 s左右，蒸发时间可延长62 s。研究证实超声波具有抑制结霜的可行性。

关键词: 超声波, 液滴群, 疏水性, 聚结, 蒸发, 表面