AI 中文总结
该研究揭示高气通量下气泡滞留于产气表面的新机制：不同大小气泡的级联聚并产生的净向下冲量累积成可抵消高浮力的滞留力，为清洁能源技术的传质优化提供了新方向。
AI 中文摘要
气泡从固体表面的脱离过程决定了清洁能源相关技术中的热、质量与电荷传输，这些技术包括高电流密度水电解和沸腾热管理。然而在高气通量下，尽管存在巨大浮力，气泡仍会被困在活性表面，严重限制传质并增加能量损失。本研究表明，这种意外的表面滞留源于不同大小气泡间的级联聚并。微电极周围的高速观测显示，当上升气泡与更小的附着于表面的后续气泡合并时，其轨迹会突然反转，以约为上升速度近两个数量级的加速度向基底加速。直接数值模拟和尺度分析表明，合并过程中不对称的界面回缩会产生无法抵消的粘性应力，从而对较小气泡产生净向下的冲量。重复的级联聚并事件会将这些瞬时冲量累积为稳定的时间平均滞留力，该力能够抵消比准静态极限高3至4个数量级的浮力。本研究发现确立了气泡聚并是一种此前未被认识到的、在高气通量下动态维持气泡滞留的机制。
英文摘要
Bubble detachment from solid surfaces governs heat, mass, and charge transport across technologies vital to clean energy, including high-current-density water electrolysis and boiling thermal management. At high gas fluxes, however, bubbles remain trapped at active surfaces despite immense buoyancy, severely restricting mass transfer and increasing energy losses. Here, we show that this unexpected surface retention originates from cascade coalescence between unequal-sized bubbles. High-speed observations around microelectrodes demonstrate that when a rising bubble merges with a smaller surface-attached successor, its trajectory abruptly reverses, accelerating toward the substrate at nearly two orders of magnitude above its rising speed. Direct numerical simulations and scaling analysis reveal that asymmetric interfacial retraction during merging generates non-canceling viscous stresses, producing a net downward impulse toward the smaller bubble. Repeated cascade coalescence events accumulate these transient impulses into a steady, time-averaged retaining force capable of opposing buoyancy three to four orders of magnitude beyond quasistatic limits. Our findings establish bubble coalescence as a previously unrecognized mechanism that dynamically sustains bubble retention under high gas flux.
