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孙姣,姜楠*,陈文义,王星.静止水中单个近壁大气泡运动特性的实验研究[J].实验力学,2019,34(6):973~980

静止水中单个近壁大气泡运动特性的实验研究

Experimental study on single large bubble rising behavior near vertical wall in stagnant water

投稿时间：2018-11-22 修订日期：2019-01-16

DOI：10.7520/1001-4888-18-254

中文关键词: 大雷诺数气泡竖直壁面轨迹变形速度

英文关键词:large Reynolds number bubble vertical wall trajectory deformation velocity

基金项目:国家自然科学基金项目(11602077， 11572357， 11732010， 11572221， 11872272， U1633109， 11802195)和国家重点研发计划资助项目(2018YFC0705300)

作者	单位
孙姣	1.天津大学机械工程学院力学系, 天津 300354； 2.河北工业大学过程装备与控制工程系, 天津 300130；3.河北工业大学工程流动与过程强化研究中心, 天津 300130
姜楠*	天津大学机械工程学院力学系, 天津 300354
陈文义	1.河北工业大学过程装备与控制工程系, 天津 300130；2.河北工业大学工程流动与过程强化研究中心, 天津 300130
王星	1.河北工业大学过程装备与控制工程系, 天津 300130；2.河北工业大学工程流动与过程强化研究中心, 天津 300130

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中文摘要:

气泡运动不稳定性直接关系到气液两相传递作用。本文利用高速摄影技术结合阴影法对静止水中大雷诺数(～O(10³))气泡在竖直壁面附近的上升运动进行实验研究，通过改变气泡与壁面初始间距，考察气泡轨迹、变形、旋转、速度及加速度等运动特征的变化规律。结果发现气泡呈二维“之”字形周期性振荡上升；与运动轨迹相对应，气泡形变、旋转角度、速度及加速度均呈周期性变化。气泡与壁面初始间距小于1.03倍气泡等效直径时，气泡与壁面发生碰撞，气泡迎面碰壁后形状发生突变，加速度达到峰值，气泡旋转背向弹开；当气泡-壁面初始间距大于1.03倍气泡等效直径时，气泡与壁面不碰撞，壁面作用减弱，气泡形状变化缓慢且不发生滚动换向，呈摆动上升，气泡逐渐远离壁面。随着气泡-壁面初始间距的增大，气泡横向摆动幅度逐渐减小，纵向跨度增大，气泡形状变化幅度逐渐减小，气泡速度和加速度变化幅度略有降低。壁面作用导致高雷诺数气泡大变形，动能与变形能周期性转化，对强化气液传热传质具有重要作用。

英文摘要:

The instability of bubble motion is directly related to the transfer interaction of gas-liquid two-phase flow. The rising behavior of large Reynolds number (O~(10³)) bubble in stagnant water near the vertical wall was investigated by means of the high-speed imaging in combination with the shadowgraph technique. The bubble motion characteristics, such as bubble trajectory, aspect ratio, rotation angle, velocity and acceleration, were analyzed by varying different distances between the bubble injection nozzle and the wall. It was found that the bubble presented a periodic zigzag ascending motion as an approximately ellipsoid. Corresponding to the bubble trajectory, the bubble deformation, rotation angle, velocity and acceleration varied periodically. When the nozzle-wall distance was less than 1.03 times of equivalent bubble diameter, the bubble collided with the wall, and the bubble shape changed abruptly after the on-coming collision, the acceleration reached the peak value, and the bubble spun backward and bounced off. While when the distance was more than 1.03 times of equivalent bubble diameter, the bubble wouldn't collide with the wall, the wall interaction decreased, the bubble shape changed slowly without rolling in reversal, the bubble wobbled up and away from the wall. With the increase of initial spacing between bubble and wall, the amplitude of transverse oscillation of the bubble decreased, the longitudinal span increased, the change of bubble shape decreased gradually, and the variation range of bubble velocity and acceleration was slightly reduced. The wall effect resulted in large deformation of high Reynolds number bubbles, and periodic transformation of kinetic energy and deformation energy, which would play an important role in enhancing gas-liquid heat and mass transfer.

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