Preferential concentration and rise velocity reduction of bubbles immersed in a homogeneous and isotropic turbulent flow
Preferential concentration and rise velocity reduction of bubbles immersed in a homogeneous and isotropic turbulent flow
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DOI：
10.1063/1.3626404
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发表时间：
2011-09-01
影响因子：
4.6
通讯作者：
Lasheras, J. C.
中科院分区：
文献类型：
--
作者：
Aliseda, A.;Lasheras, J. C.
本文对球形小气泡在重流体均质各向同性湍流载流中的行为进行了实验研究。将直径在10 μ m和900 μ m之间的气泡注入水平水道的试验段中，并使其与位于试验段入口处的网格引起的湍流相互作用。点测量的气泡直径和对流和上升速度从光干涉测量数据，连同流动可视化，显示瞬时浓度场的载流中的气泡。湍流对气泡的影响被发现改变气泡的浓度场，导致在小尺度上的优先积累，一种被称为聚类的现象，以及在流动中的气泡的上升速度低于在静止流体中的气泡的测量和预测的值的降低。这些结果被解释在一个不均匀的流动中的气泡上作用的不同的力，特别是作为优先驱动的气泡的旋涡的核心的压力波动的影响。(C)2011年美国物理学会。[doi：10.1063/1.3626404]
The behavior of small spherical bubbles immersed in a homogeneous isotropic turbulent carrier flow of a heavier fluid has been experimentally studied. Air bubbles with diameters between 10 and 900 mu m were injected in the test section of a horizontal water channel and allowed to interact with the turbulence induced by a grid located at the entrance to the test section. Point measurements of the bubble diameter and convective and rise velocities were taken from light interferometry data, together with flow visualizations that showed the instantaneous concentration field of bubbles in the carrier flow. The effect of the turbulence on the bubbles was found to alter the concentration field of bubbles leading to preferential accumulation at small scales, a phenomenon referred to as clustering, and to a decrease in the rise velocity of bubbles in the flow below the value measured and predicted for bubbles in a stationary fluid. These results are interpreted in terms of the different forces acting on the bubble in an inhomogeneous flow and in particular as the effect of pressure fluctuations that drive the bubbles preferentially to the core of vortices. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3626404]