School of Electronic and Information Engineering, Liaoning Technical University, Huludao 125105, China.
School of Electronic and Information Engineering, Liaoning Technical University, Huludao 125105, China.
Ultrason Sonochem. 2021 Jun;74:105577. doi: 10.1016/j.ultsonch.2021.105577. Epub 2021 Apr 25.
The circular motion of submillimeter-sized bubbles attached to a boundary in an 18.5 kHz ultrasonic field are investigated experimentally by high-speed photography and image analysis. It is found that the vibration of gas bubbles with diameters of 0.2-0.4 mm is between spherical radial vibration and regular surface fluctuation. Different from the circular motion of suspended bubbles in water, the circular motion of gas bubbles attached to a boundary presents some new characteristics. These bubbles attached to a boundary (wandering bubbles) will rotate around a fixed bubble array (holding bubbles). Both the wondering bubbles and holding bubbles are "degas" bubbles. The primary Bjerknes force acting on wandering bubbles in the acoustic wave field and the secondary Bjerknes force between the wandering bubbles and the holding bubbles strongly affects the circular motion. The circling and residence behavior of gas bubbles is described and analyzed in detail, which is helpful to understand and improve industrial applications such as ultrasonic cleaning, sonochemical treatment, aeration and cavitation reduction.
通过高速摄影和图像分析实验研究了附着在边界上的亚毫米大小的气泡在 18.5kHz 超声场中的圆周运动。结果发现，直径为 0.2-0.4mm 的气泡的振动介于球型径向振动和规则表面波动之间。与悬浮在水中的气泡的圆周运动不同，附着在边界上的气泡的圆周运动呈现出一些新的特征。这些附着在边界上的气泡（游动气泡）将围绕固定的气泡排列（保持气泡）旋转。游动气泡和保持气泡都是“脱气”气泡。作用在声场中游动气泡上的主要 Bjerknes 力和游动气泡与保持气泡之间的次级 Bjerknes 力强烈影响着圆周运动。详细描述和分析了气体气泡的盘旋和停留行为，这有助于理解和改进超声清洗、声化学处理、曝气和空化抑制等工业应用。
