Xiao Jian, Zhang Jinxin
School of Intelligent Manufacturing, Dongguan University of Technology-City College, Guangdong 523419, China.
School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510641, Guangdong, China.
Ultrason Sonochem. 2023 May;95:106365. doi: 10.1016/j.ultsonch.2023.106365. Epub 2023 Mar 13.
Bubble dynamics is important in flow boiling of minichannel, and ultrasonic field effects bubble behaviors. However, flow boiling bubble movements in minichannels under ultrasonic field have received little research attention and are still poorly understood. In this paper, the effects of ultrasonic field on bubble dynamics are experimentally studied by capturing the bubble motion behaviors of the flow boiling bubbles. The ultrasonic frequencies are set to 23, 28, 32, and 40 kHz. Bubble tracking algorithm, which studies the growth, trajectories, velocities, and traveled distances for bubbles, is created to qualitatively describe bubble motion behavior of flow boiling in minichannel. It is found that after the application of ultrasound, the detachment frequency, velocity, and travel distance of the bubbles significantly increases, and the growth behavior and trajectory are extremely complex, the two-phase gas-liquid flow is extremely unstable. The bubbles gain kinetic energy as the ultrasound frequency increases. Finally, numerical simulations are used to quantitatively investigate the mechanism of bubble motion in microchannels under ultrasonic fields.
气泡动力学在微通道流动沸腾中很重要，并且超声场会影响气泡行为。然而，超声场作用下微通道内流动沸腾气泡的运动很少受到研究关注，目前仍了解不足。本文通过捕捉流动沸腾气泡的运动行为，对超声场对气泡动力学的影响进行了实验研究。超声频率设置为23、28、32和40kHz。创建了气泡跟踪算法，该算法研究气泡的生长、轨迹、速度和行进距离，以定性描述微通道内流动沸腾的气泡运动行为。研究发现，施加超声后，气泡的脱离频率、速度和行进距离显著增加，并且生长行为和轨迹极其复杂，气液两相流极不稳定。随着超声频率的增加，气泡获得动能。最后，通过数值模拟定量研究了超声场下微通道中气泡的运动机理。
