液滴喷射带电
Drop Spray Electrification
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中文总结 AI 辅助
该研究揭示了水滴撞击超疏水网格时的带电机制，明确了韦伯数、网格孔隙等对电荷的影响，为喷雾带电和雨水驱动能量收集提供了超疏水网格平台的设计原理。
中文摘要 AI 辅助
自早期对瀑布和喷雾带电的研究以来，人们就已认识到水滴破碎过程中的电荷分离现象，但结构化拒液表面处受控液滴破碎的作用仍不清楚。本文表明，撞击超疏水网格的水滴会在液体渗透并破碎通过网格孔隙时产生带电的二次液滴。结合法拉第杯电荷测量与高速成像，我们确定了电荷如何依赖于韦伯数和喷雾形成路径。在渗透阈值以下未检测到可测量电荷；低韦伯数下，反冲射流形成会产生高的单位喷雾质量电荷；中等韦伯数下，反冲射流和冲击诱导射流共同贡献带电；高韦伯数下，薄饼状弹跳抑制反冲射流形成，因此带电由冲击诱导渗透主导，总电荷趋近饱和值。我们还发现，更小的网格孔隙可提升电荷质量比，导电网格则能通过耗散残余表面电荷在多次撞击下提供稳定带电。这些发现为超疏水网格平台的喷雾带电和雨水驱动能量收集提供了设计原理。
英文摘要
Charge separation during the breakup of water drop has been recognized since the early studies of waterfall and spray electrification, yet the role of controlled drop fragmentation at structured liquid-repellent surfaces remains unclear. Here we show that water drops impacting superhydrophobic meshes generate charged secondary droplets as liquid penetrates and fragments through the mesh pores. By combining Faraday-cup charge measurements with high-speed imaging, we identify how the charge depends on the Weber number and on the pathway of spray formation. No measurable charge is detected below the penetration threshold. At low Weber numbers, recoil jet formation gives a high charge per unit spray mass, whereas at intermediate Weber numbers both recoil jets and impact-induced jets contribute to charging. At higher Weber numbers, pancake bouncing suppresses recoil jet formation, so charging is dominated by impact induced penetration and the total charge approaches a saturated value. We further show that smaller mesh pores enhance the charge-to-mass ratio and that conductive meshes provide stable charging under repeated impacts by dissipating residual surface charge. These findings provide design principles for superhydrophobic mesh platforms for spray charging and rain-driven energy harvesting.
