Breaking the symmetry to suppress the Plateau\u2013Rayleigh instability and optimize hydropower utilization

Zhipeng Zhao,Wei Fang,Huizeng Li,Zheren Cai,An Li,Yanlin Song,Xiqiao Feng,Mingzhu Li

doi:10.1038/s41467-021-27237-0

Abstract

Droplet impact on solid surfaces is essential for natural and industrial processes. Particularly, controlling the instability after droplet impact, and avoiding the satellite drops generation, have aroused great interest for its significance in inkjet printing, pesticide spraying, and hydroelectric power collection. Herein, we found that breaking the symmetry of the droplet impact dynamics using patterned-wettability surfaces can suppress the Plateau–Rayleigh instability during the droplet rebounding and improve the energy collection efficiency. Systematic experimental investigation, together with mechanical modeling and numerical simulation, revealed that the asymmetric wettability patterns can regulate the internal liquid flow and reduce the vertical velocity gradient inside the droplet, thus suppressing the instability during droplet rebounding and eliminating the satellite drops. Accordingly, the droplet energy utilization was promoted, as demonstrated by the improved hydroelectric power generation efficiency by 36.5%. These findings deepen the understanding of the wettability-induced asymmetrical droplet dynamics during the liquid–solid interactions, and facilitate related applications such as hydroelectric power generation and materials transportation.

Highlights

Droplet impact on solid surfaces is essential for natural and industrial processes
It is still challenging to regulate the Plateau–Rayleigh instability during droplets rebounding on solid surfaces due to the fast retraction velocity of the droplet and the excessive velocity gradient inside the droplet, which elongate the liquid column and induce the generation of satellite drops
We propose that using patterned-wettability substrates, the symmetry of the droplet impact dynamics can be broken, which suppresses the Plateau–Rayleigh instability during the droplet rebounding process, and improves the hydroelectric energy collection efficiency

Summary

Introduction

Droplet impact on solid surfaces is essential for natural and industrial processes. controlling the instability after droplet impact, and avoiding the satellite drops generation, have aroused great interest for its significance in inkjet printing, pesticide spraying, and hydroelectric power collection. The gyrating and dancing of droplets are realized through heterogeneous surface wettability regulation[33], and droplet directional bouncing and materials transportation[36,37,38,39] have been achieved by constructing patterned-wettability surface where the droplet lateral velocity is found to be related to the surface area of a geometric region[36,37] During these rebounding processes, satellite drops may still be produced due to Plateau–Rayleigh instability. We propose that using patterned-wettability substrates, the symmetry of the droplet impact dynamics can be broken, which suppresses the Plateau–Rayleigh instability during the droplet rebounding process, and improves the hydroelectric energy collection efficiency. These findings provide insights into the asymmetrical liquid–solid dynamics, and inspire the innovative design of functional surfaces for liquid instability suppression, high-performance hydroelectric energy collection, and droplet directional transportation

Methods

Results

Conclusion