Breaking the symmetry to suppress the Plateau–Rayleigh instability and optimize hydropower utilization

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.

Droplet Bouncing: Fundamentals, Regulations, and Applications

“…Surface Wettability Gradient: Making millimeter-sized droplet move toward the designed direction is desired in wide liquid-manipulation-related [125][126][127][128][129][130][131][132][133] applications like liquid collection, [134][135][136][137][138][139][140][141][142][143][144][145][146][147][148][149][150] printing, [151] hydropower utilization optimization [152,153] or microfluidics. [154,155] By designing a nonwetting solid surface with a wettability gradient, vertical momentum of impacting droplet can be transferred to horizontal momentum with the designed direction.…”

Non‐Hookean Droplet Spring for Enhancing Hydropower Harvest

“…Inspired by lotus leaves and beetles, wettability, especially heterogeneous wettability, provides an effective way to manipulate droplet behaviors. [19][20][21][22][23][24][25] In this work, we fabricate droplet-based springs using two parallel plates with heterogeneous wettability, and investigate their non-Hookean elastic mechanics under pressing and stretching. We demonstrate that the nonlinear behaviors of the spring can be well manipulated by the droplet volume, droplet number, and especially the wettability patterns on the parallel plates.…”

Directional transport of droplets impacting on superhydrophobic opening triangular groove surfaces

“…Chu et al [8] reported that when the droplet impacted on the boundary between the superhydrophobic part and hydrophilic part, the directional transport distance of the droplet can be controlled by changing the proportion of the impinging droplet in the hydrophilic part. Zhao et al [9] investigated the droplet impacting on a heterogenous superhydrophobic surface with hydrophilic strips, and quantitatively manipulated the directional transport distance of the droplet and suppressed the Plateau-Rayleigh instability successfully [10]. However, these surfaces exist many defects such as droplet loss, mixing, and contamination due to the hydrophilic regions.…”