非均匀直流电场作用下气泡的生长变形与脱离特性实验研究  

Experimental Investigation on Characteristics of Growth Deformation and Detachment of Bubbles Under Non-uniform DC Electric Field

作　　者：吴天一 王军锋[1] 张伟[1] 詹水清[1] 苏巧玲 WU Tianyi;WANG Junfeng;ZHANG Wei;ZHAN Shuiqing;SU Qiaoling(School of Energy and Power Engineering,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]江苏大学能源与动力工程学院,镇江212013

出　　处：《高电压技术》2022年第9期3574-3581,共8页High Voltage Engineering

基　　金：国家自然科学基金国际合作与交流项目(51761145011)。

摘　　要：电场强化多相系统相间分散技术被广泛应用于化工领域。气泡生长过程决定着气泡脱离后的尺寸和分散特性,它们是影响传热传质效率的重要因素。为此搭建了静电气液分散可视化实验系统,利用显微高速摄像技术对非均匀电场下液体电介质中的气泡生长过程进行了微观可视化研究,通过对实验获得的气泡生长及脱离过程的微观图像进行处理分析,归纳了气泡生长变形与脱离的多种动态特征。实验结果表明:气泡生长可分为4种特征区别明显的模式,包括滴状分离、锥形分离、扭结分离和枝杈破碎;受荷电弛豫效应影响,自由电荷在气液界面局部聚集,使库仑力作用强度不均匀,宏观表征为气泡表面波动;随电场强度的增大,气泡沿电场方向被拉伸且气液界面的波动程度加剧,气液界面稳定性被电场力削弱,最终气泡破碎形成微气泡群。该研究可为电场作用下气泡脱离尺寸和脱离频率的控制提供参考。The technology of using electric field to enhance the inter-phase dispersion of multi-phase systems is widely used in chemical industry. The bubble growth process determines the size and dispersion characteristics of the detached bubbles, which are important factors affecting the heat and mass transfer efficiency. To this end, a visual experimental system of electrostatic gas-liquid dispersion was built, and the micro high-speed photography technology was used to conduct microscopic visualization investigations into the bubble growth process in liquid dielectrics under non-uniform electric field. By processing and analyzing the microscopic images of the bubble growth and detachment process obtained from the experiments, the dynamic characteristics of the growth deformation and detachment of the bubbles were summarized. The experimental results indicate that the bubble growth can be divided into four distinct patterns, including the dripping separation, the cone separation, the kink separation, and the branching fragmentation. Affected by the charge relaxation effect, free charges are locally aggregated at the gas-liquid interface, resulting in a non-uniform Coulombic force,which is macroscopically characterized by bubble surface fluctuations. As the electric field intensity increases, the bubbles are stretched in the direction of the electric field and the fluctuation degree of the gas-liquid interface is intensified.The stability of the gas-liquid interface is weakened by the electric field forces and the bubbles finally break up into a cluster of micro bubbles. This research can provide a reference for controlling the bubble detachment size and frequency under the electric field.

关 键 词：漏电介质 气泡生长模式 拉伸特性 界面波动 脱离频率 

分 类 号：O441.1[理学—电磁学] TQ021[理学—物理]