Effect of gravity levels on the flow pattern modulation by the phase separation concept
Effect of gravity levels on the flow pattern modulation by the phase separation concept
复制标题
重力水平对相分离概念的流型调制的影响
DOI：
10.1016/j.compfluid.2014.11.028
复制
发表时间：
2015-02
影响因子：
2.8
通讯作者：
邢峰
中科院分区：
文献类型：
--
作者：
孙东亮;徐进良;王艳宁;谢剑;邢峰
将网状圆柱体悬挂在管中，利用环形区域中的气泡来调节流动模式，从而在管壁上形成薄液膜。我们研究了重力水平对调制流型的影响。流体体积 (VOF) 方法模拟裸管和调制流动截面中的段塞气泡序列流动。沿流动方向的气泡群体密度（β）和平均液膜厚度（δα）合成参数β/δato来表征相变传热的增强。研究发现，在地球正常重力作用下，出现逆流，环形区域出现快速向上的流动，核心区域出现向下的液体流动。由于稀疏的气泡和薄液膜而形成较低的β，从而形成较大的β/δ，从而增强相变传热。环形区域中的快速流体运动和三个长度尺度的液体循环增强了液体塞中的对流换热。在微重力下，除了网状圆柱体内部的液层向下流动外，环形区和核心区均呈准并流，呈向上流动。气泡比正常重力下的气泡更密集。液体循环仅发生在气泡长度范围内。在微重力下，两相在环形区和核心区均以并流方式彻底分离。气体流动缓慢，气体停留时间增加，导致β=1。液膜超薄。这两个因素产生显着大的β/δ以增强相变传热。我们证明了相分离概念在微型和微重力环境下的有效性。
Suspending a mesh cylinder in a tube modulates flow patterns with gas bubbles in the annular region to form thin liquid film on the wall. We investigate the effect of gravity levels on the modulated flow patterns. The volume of fluid (VOF) method simulates the slug bubble train flow in bare tube and modulated flow sections. The bubble population density along the flow direction (β) and averaged liquid film thickness (δα) synthesize a parameterβ/δato characterize the enhancement of phase change heat transfer. It is found that at the normal gravity on earth, counter-flow appears with fast upward flow in the annular region and downward liquid flow in the core region. A lowerβdue to sparsely populated bubbles and thin liquid film form a largerβ/δato enhance the phase change heat transfer. Convective heat transfer in liquid plugs is enhanced by the fast fluid movement in the annular region and liquid circulations at three length scales. At the miniature gravity, quasi-co-current flow happens with upward flows in both annular region and core region, except that a liquid layer inside mesh cylinder flows downward. Bubbles are more densely populated than those at the normal gravity. Liquid circulation occurs only at the bubble length scale. At the micro gravity, the two-phases are thoroughly separated with co-current flows in both annular region and core region. Gas flows slowly and the residence time of gas is increased to result inβ= 1. Τhe liquid film is ultra-thin. These two factors create a significantly largeβ/δato enhance the phase change heat transfer. We demonstrate the effectiveness of the phase separation concept at miniature and micro gravity environment.
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DOI：
10.1016/j.ijmultiphaseflow.2006.09.007
发表时间：
2007-04
影响因子：
3.8
作者：
M. Salewski;L. Fuchs
通讯作者：
M. Salewski;L. Fuchs
DOI：
10.4271/981692
发表时间：
1998-07
期刊：
--
影响因子：
--
作者：
A. Delil
通讯作者：
A. Delil
DOI：
10.1016/j.ijmultiphaseflow.2012.03.004
发表时间：
2012-07
影响因子：
3.8
作者：
S. Morales-Ruiz;J. Rigola;I. Rodríguez;A. Oliva
通讯作者：
S. Morales-Ruiz;J. Rigola;I. Rodríguez;A. Oliva
影响因子：
4.5
作者：
A. Miyara;Yusuke Otsubo
通讯作者：
A. Miyara;Yusuke Otsubo
DOI：
10.1016/j.ijheatfluidflow.2009.02.019
发表时间：
2009-10-01
影响因子：
2.6
作者：
Han, Youngbae;Shikazono, Naoki
通讯作者：
Shikazono, Naoki