Effects of surface tension on the dynamics of a single micro bubble near a rigid wall in an ultrasonic field

Ultrasonics Sonochemistry

Hao Zheng¹  Haixia Yu²  Claus-Dieter Ohl³  Hao Wu⁴  Dachao Li⁴  Yuanyuan Li⁴ 

[1] Innovative Institute of Chinese Medicine and Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan 250355, PR China;Department of Soft Matter, Institute of Physics, Otto-von-Guericke University, Magdeburg 39106, Germany;Innovative Institute of Chinese Medicine and Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan 250355, PR China;State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, PR China;

关键词: Acoustic cavitation;    Surface tension;    Bubble dynamics;    Micro-jet;    Bubble collapse;   

DOI  :  

来源: DOAJ

【 摘 要 】

Acoustic cavitation is a very important hydrodynamic phenomenon, and is often implicated in a myriad of industrial, medical, and daily living applications. In these applications, the effect mechanism of liquid surface tension on improving the efficiency of acoustic cavitation is a crucial concern for researchers. In this study, the effects of liquid surface tension on the dynamics of an ultrasonic driven bubble near a rigid wall, which could be the main mechanism of efficiency improvement in the applications of acoustic cavitation, were investigated at the microscale level. A synchronous high-speed microscopic imaging method was used to clearly record the temporary evolution of single acoustic cavitation bubble in the liquids with different surface tension. Meanwhile, the bubble dynamic characteristics, such as the position and time of bubble collapse, the size and stability of the bubbles, the speed of bubble boundaries and the micro-jets, were analyzed and compared. In the case of the single bubbles near a rigid wall, it was found that low surface tension reduces the stability of the bubbles in the liquid medium. Meanwhile, the bubbles collapse earlier and farther from the rigid wall in the liquids with lower surface tension. In addition, the surface tension has no significant influence on the speed of the first micro-jet, but it can substantially increase the speed of second and the third micro-jets after the first collapse of the bubble. These effects of liquid surface tension on the bubble dynamics can explain the mechanism of surfactants in numerous fields of acoustic cavitation for facilitating its optimization and application.

【 授权许可】

Unknown