Evolution of flow patterns and the associated heat and mass transfer characteristics during flow boiling in mini-/micro-channels
Evolution of flow patterns and the associated heat and mass transfer characteristics during flow boiling in mini-/micro-channels
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微型/微通道中流动沸腾过程中流动模式的演变以及相关的传热传质特性
DOI：
10.1016/j.cej.2016.08.034
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发表时间：
2016-12
影响因子：
15.1
通讯作者：
Jia H. W.
中科院分区：
文献类型：
--
作者：
Zhang P.;Jia H. W.
采用耦合的Level-set（LS）/Volume of Fluid（VOF）方法（CLSVOF）对微小/微通道内的流动沸腾进行了三维数值模拟。基于界面温度梯度的相变模型的实现和数值方法是第一次验证文献中的实验和数值结果。用一个人工空腔代替传统的种泡或局部沸腾的方法作为核化位置，在这里只发生沸腾，并出现周期性的单泡流。观察到了泡状流、弹状流和环状流的流型转变，计算得到的壁温与实验结果吻合较好。汽泡径向直径和轴向长度的增长与实验数据进行了比较，发现汽泡径向直径的增长与实验数据吻合较好，而轴向长度的增长与实验数据有偏差，这是由于汽泡在成核位置附近过早聚并所致。同时，局部换热系数被发现显着影响的流动模式。定量地研究了沿流动方向沿着五个有代表性的位置处的局部干度的变化，发现其波动与局部流型相一致。最后，我们对具有两个形核位置的流动沸腾进行了数值模拟，显示了该数值方法在处理复杂流动沸腾过程中的良好潜力。本文所提供的信息对小型/微型反应器的设计和操作是非常有用的。
A three-dimensional numerical investigation of flow boiling in mini-/micro-channels is carried out using a coupled Level-set (LS)/Volume of Fluid (VOF) method (CLSVOF) in the present study. A phase change model based on the interfacial temperature gradient is implemented and the numerical approach is first validated by the experimental and numerical results in the literature. A fabricated cavity in lieu of the traditional methods of seed bubble or local superheat is treated as the nucleation site, where boiling occurs exclusively and periodic stream of single bubble emerges. The transitions of flow patterns from bubbly flow to slug flow and annual flow are observed, and the numerical wall temperatures agree with the experimental results. The growths of the radial diameter and axial length of vapor bubble are compared with the experimental data, and good agreement is found for the radial diameter while deviation is found for the axial length due to early coalescence of bubbles near the nucleation site. Meanwhile, the local heat transfer coefficients are found to be significantly influenced by the flow patterns. The variations of the local vapor qualities at five representative locations along the flow direction are also studied quantitatively and the fluctuations are found to be consistent with the local flow patterns. Finally, we present a numerical attempt on flow boiling with two nucleation sites, which shows a good potential of the present numerical approach to deal with the complicated flow boiling process. The information presented here is very useful to the design and operation of the mini-/micro-reactors.
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DOI：
10.1115/ht-fed2004-56268
发表时间：
1998-04
期刊：
Volume!
影响因子：
--
作者：
G. Tryggvason;A. Esmaeeli
通讯作者：
G. Tryggvason;A. Esmaeeli
影响因子：
3.2
作者：
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通讯作者：
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影响因子：
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作者：
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Lei Zhang;M. Shoji
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影响因子：
2
作者：
Ling, Kong;Li, Zeng-Yao;Tao, Wen-Quan
通讯作者：
Tao, Wen-Quan
DOI：
10.1016/j.ijrefrig.2010.07.013
发表时间：
2010-11
期刊：
International Journal of Refrigeration-revue Internationale Du Froid
影响因子：
--
作者：
C. Kunkelmann;P. Stephan
通讯作者：
C. Kunkelmann;P. Stephan