Thermocapillary Flow and Aggregation of Bubbles on a Solid Wall.
Thermocapillary Flow and Aggregation of Bubbles on a Solid Wall.
复制标题
固体壁上气泡的热毛细流动和聚集。
DOI：
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发表时间：
2000
影响因子：
9.9
通讯作者：
Sides
中科院分区：
文献类型：
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作者：
Kasumi;Solomentsev;Guelcher;Anderson;Sides
理论表明，热壁上液体中相邻气泡周围的热毛细管流动将气泡拉到一起。垂直于壁的温度梯度在气泡-液体界面处建立表面张力梯度，这反过来又维持剪切应力梯度，将邻近的流体泵离壁。相邻的气泡在该流动中相互夹带，并且还热泳地响应温度近场中的横向温度梯度。该理论预测聚集速度与温度梯度、气泡半径、表面张力相对于温度的导数以及液体粘度的倒数成比例。在受控条件下进行气泡聚集实验来检验该理论。当气泡间间隔大于 3 个半径时，根据该理论缩放实验气泡轨迹会基本上将所有数据折叠到主曲线上，这表明该理论是正确的。当考虑到壁面对气泡运动的阻碍时，计算的速度与实验结果一致。描述阻碍效应的参数值是通过将数据与理论拟合、独立测量以及直接流体动力学计算获得的。三个确定的结果在参数值的可能范围的15%内一致。版权所有 2000 学术出版社。
Theory suggests that thermocapillary flow about neighboring bubbles in liquids on hot walls pulls the bubbles together. A temperature gradient perpendicular to the wall establishes a surface tension gradient at the bubble-liquid interface, which in turn sustains a shear stress gradient that pumps adjacent fluid away from the wall. Neighboring bubbles are mutually entrained in this flow and also respond thermophoretically to lateral temperature gradients in the temperature near field. The theory predicts that the aggregation velocity scales with the temperature gradient, the radius of the bubbles, the derivative of the surface tension with respect to temperature, and the reciprocal of the liquid's viscosity. Bubble aggregation experiments under controlled conditions were performed to test the theory. Scaling the experimental bubble trajectories according to the theory substantially collapses all of the data onto a master curve when the interbubble separation is greater than 3 radii, which suggests that the theory is correct. Calculated velocities agree with the experimental results when hindrance of bubble motion due to the wall is included. Values for the parameter that describes the hindrance effect are obtained from fitting the data to the theory, from independent measurements, and from direct hydrodynamic calculation. The results of the three determinations agree within 15% of the possible range of the value of the parameter. Copyright 2000 Academic Press.