Drag Coefficients of Single Bubbles under Normal and Micro Gravity Conditions
Drag Coefficients of Single Bubbles under Normal and Micro Gravity Conditions
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DOI：
10.1299/jsmeb.41.472
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发表时间：
1998-05
期刊：
影响因子：
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通讯作者：
A. Tomiyama;I. Kataoka;I. Zun;T. Sakaguchi
中科院分区：
文献类型：
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作者：
A. Tomiyama;I. Kataoka;I. Zun;T. Sakaguchi
基于作用在静止液体中气泡上的力的平衡以及单个气泡终端上升速度的可用经验相关性，开发了在各种流体特性、气泡直径和重力加速度下单个气泡的阻力系数 CD 的简单但可靠的相关性。提出的 CD 由三个方程组成，每个方程对应于纯系统、轻度污染系统和污染系统。通过引入有效物体加速度的概念，还考虑了由于液体流动而产生的摩擦压力梯度的影响。利用所提出的CD计算单个气泡的末端上升速度，并与10-2<Eo<103、10-14<M<107和10-3<Re<105条件下的实测数据进行比较，其中Eo、M和Re分别为Eotvos数、Morton数和气泡雷诺数。结果证实，所提出的 CD 比现有的阻力系数模型能提供更好的预测。
Simple but reliable correlations for a drag coefficient, CD, of single bubbles under a wide range of fluid properties, bubble diameter and acceleration of gravity were developed based on a balance of forces acting on a bubble in a stagnant liquid and available empirical correlations of terminal rising velocities of single bubbles. The proposed CD consists of three equations, each of which corresponds to pure, slightly contaminated and contaminated systems. The effect of a frictional pressure gradient due to a liquid flow is also taken into account by introducing a concept of an effective body acceleration. Terminal rising velocities of single bubbles were calculated using the proposed CD, and compared with measured data under the condition of 10-2<Eo<103, 10-14<M<107 and 10-3<Re<105 where Eo, M and Re are Eotvos, Morton and bubble Reynolds numbers, respectively. As a result, it was confirmed that the proposed CD gives better predictions than available drag coefficient models.