垂直磁场作用下水平微电极表面气泡生长特性实验研究

来源期刊:中南大学学报(自然科学版)2021年第1期

论文作者:詹水清 黄雨捷 王军锋 江明镅 张伟 王贞涛

文章页码:249 - 259

关键词:垂直磁场;气泡生长;脱离直径;生长时间;电极电势

Key words:vertical magnetic field; bubble growth; departure diameter; growth time; potential of working electrode

摘    要:为探究不同电磁场产生的微观磁对流对水平微电极表面单个气泡生长行为的影响,建立恒定电流的电解水制氢实验系统。应用高速摄像可视化技术对电极表面气泡生长过程进行观察,结合OpenCV-Python自定义程序对气泡生长行为特征参数进行提取和分析。研究结果表明:在气泡生长周期内,气泡直径逐渐增大,气泡生长速率先增大后减小,外加磁场对气泡生长速率几乎没有影响,气泡生长速率随电解电流密度的增大而增大。与低电解电流密度工况相比,高电解电流密度下的气泡脱离直径明显偏大,气泡生长时间明显延长,工作电极电势明显偏高。随着磁感应强度增大,低电解电流密度和高电解电流密度条件下的气泡脱离直径、气泡生长时间和工作电极电势均呈现相反的变化趋势,高强度磁场或高电解电流密度作用使磁场的影响效果减弱。不同电解电流密度和磁感应强度下工作电极电势与气泡接触直径的变化规律类似,揭示出工作电极电势变化与电极表面气泡生长行为密切相关。

Abstract: To investigate the effects of micro magnetohydrodynamics convection produced by electric and magnetic fields on the growth characteristics of a single bubble on horizontal microelectrode surface, a constant-current chronopotentiometry water electrolysis experiment system was built. The bubble growth process was captured by adopting the high-speed image technology, and the characteristic parameters of bubble growth were extracted and analyzed in conjunction with a specially OpenCV-Python program. The results show that the bubble diameter increases during the bubble growth cycle. The bubble growth rate first increases and then decreases and the external magnetic field has little effect on it. The bubble growth rate increases with the increase of the applied electrolysis current density. The bubble departure diameter is greatly increased, and the bubble growth time is obviously long and the potential of working electrode is obviously high at high electrolysis current densities, compared to those under conditions of low electrolysis current densities. With increasing magnetic induction, bubble departure diameter, the bubble growth time and the potential of working electrode show the reverse change trend between the low and high electrolysis current densities, and the effects of magnetic field are decreased significantly with high-intensity magnetic field or high electrolysis current density. The potential of working electrode and the bubble contact diameter perform similar variations at different electrolysis current densities and magnetic inductions, which reveals that the transient potential of working electrode is closely associated with the bubble growth characteristics on the horizontal microelectrode surface.

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