乙醇液滴冲击过冷水平壁面的铺展行为实验研究

This study aims to investigate the effect of surface tension on the spreading dynamics of a droplet impacting a supercooled substrate. To accomplish this, a visualization experimental system is established. The influence of substrate supercooling on the spreading dynamics of low surface tension droplet is analyzed. In the experiment, hydrophilic silicon substrate and a smaller impact velocity are used to observe the spreading dynamics of an ethanol droplet impacting the supercooled substrate. In addition, this study compares the applicability of typical models with different maximum spreading factor and maximum spreading time to the spreading dynamic factors of an ethanol droplet impacting supercooled substrate. The results demonstrate that the spreading dynamics of an ethanol droplet impacting the supercooled hydrophilic substrate can be divided into three stages: splash, spreading, and stability. The maximum spreading time decreases with an increase in substrate supercooling. Moreover, the influence of substrate supercooling on the maximum spreading factor is non-monotonic. At low substrate supercooling, the reduction of the maximum internal spreading factor plays a dominant role. Conversely, at high substrate supercooling levels, the enhancement of Rayleigh-Taylor instability leads to an increase in the "fingering-like" protrusion of the infinite chain plays a major role. The combined effect of the two causes non-monotonic changes. The existing models have good predictive performance for the maximum spreading time, with a relative mean error of 6. 05%. However, their predictive accuracy for the maximum spreading factor is poor.