为了有效调控中尺度气泡的行为,在纯水中通过添加不同浓度的3种表面活性剂实验研究了气泡上升过程中的形状与速度的变化.在一个方截面柱形容器内生成了4种中尺度气泡,再利用高速摄影仪记录了气泡的瞬时运动过程,通过图像处理软件分析了气泡的形状和速度.结果表明,由于Marangoni效应,适量的表面活性剂可以有效抑制中尺度气泡的变形,减小气泡的形状变化幅度,降低气泡的上升速度.相比于纯水,当曲拉通的浓度为0.15 mmol/L时,气泡高宽比的变化幅度缩减了57％；当曲拉通的浓度为0.05 mmol/L时,气泡终端上升速度降低了35％.实验中还发现,气泡的形状变化影响着气泡的瞬时速度,气泡高度比越小,上升得越快.在实验条件范围内,不同表面活性剂对气泡的调控效果有所不同,曲拉通的调控效果优于聚乙二醇和正戊醇.%Experiments were conducted on the variations of shape and velocity of single bubbles during rising in three types of surfactant solutions with different concentration in order to effectively modulate the behavior of meso-scale bubbles in bubbly flow. Single bubbles with the size of 1. 3-6 mm were generated in a square glass column, and the instantaneous motion of single bubbles was recorded using a high-speed camera. Then bubble shape and velocity were determined from the recorded frames using the image analysis software. The results show that the right concentration of surfactants used here would dampen bubble deformation, reduce shape oscillation amplitude and slow down the bubble rise velocity significantly due to the Marangoni effect. The addition of 0. 15 mmol/L Triton X-100 would reduce the oscillation amplitude of the bubble aspect ratio by 57% while the addition of 0. 05 mmol/L Triton X-100 would lower the terminal velocity of bubbles by 35% compared with those in pure water. Moreover, The bubble shape oscillation would influence the bubble transient velocity. It seems that under the present experimental conditions, the modulation effect of the addition of different types of surfactants on meso-scale bubble behavior is quite different. The addition of Triton X-100 has stronger effect on the modulation than the addition of Polyethylene glycol or n-Pentanol.
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