Spatially periodic vapor bubble activity during subcooled pool boiling on 1D aluminum alloy micro-fin arrays
Spatially periodic vapor bubble activity during subcooled pool boiling on 1D aluminum alloy micro-fin arrays
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DOI：
10.1016/j.ijheatmasstransfer.2021.121760
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发表时间：
2021-12
影响因子：
5.2
通讯作者：
Brendon Doran;Bin Zhang;Shayan Davani;K. Osafo;Owen Sutka;A. Walker;N. Mueller;Stephen Akwaboa;P. Mensah;W. Meng;A. Moore
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文献类型：
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作者：
Brendon Doran;Bin Zhang;Shayan Davani;K. Osafo;Owen Sutka;A. Walker;N. Mueller;Stephen Akwaboa;P. Mensah;W. Meng;A. Moore
在微观和纳米尺度表面改性以改善池沸腾性能的广泛领域中，微鳍阵列尤其具有吸引力，因为与宏观鳍相比，它们能够在最小尺寸或重量增加的情况下显着增加湿表面积。此外，与更随机的替代方案相比，它们的规则和重复几何形状为参数优化、均匀性和可重复性提供了更大的潜力。然而，在被加热的表面上存在一个规则的、重复的微尺度图案，已经被证明可以在小长度尺度上产生液体和蒸汽流动的交替区域，这可以强烈影响表面的宏观传热性能。本文采用池沸腾实验、高速成像和数值模拟相结合的方法，研究了介质冷却剂HFE-7100中一维（1D）铝合金微翅片阵列的汽泡行为和池沸腾换热特性。结果表明，一维微鳍阵列的存在可以显著提高池沸腾性能，但与平面无图案基线表面相比，微鳍阵列的存在对池沸腾性能有重要的（有时不是直观的）依赖性。实验数据表明，表面面积的简单增加并不一定与传热性能的改善有关，而高速成像显示，除了明显的气泡迁移行为外，微鳍的存在还引起了一系列周期性的向上和向下流动模式。这些结果扩大了表面类型和工作流体的范围，这些类型和工作流体通过微尺度表面改性产生了空间周期性和独特的液体/蒸汽传输途径。
Within the broad field of micro- and nano- scale surface modification to improve pool boiling performance, micro-fin arrays are especially attractive due to their ability to significantly increase wetted surface area with minimal increase in size or weight compared to macroscopic fins. In addition, their regular and repeating geometry enables greater potential for parametric optimization, uniformity, and repeatability as compared to more randomized alternatives. However, the presence of a regular, repeating microscale pattern on a heated surface has previously been shown to create alternating regions of liquid and vapor flow at small length scales which can strongly affect the macroscopic heat transfer performance of the surface. In this work, a combination of pool boiling experiments, high-speed imaging, and numerical modeling were used to investigate vapor bubble behavior and pool boiling heat transfer characteristics from one-dimensional (1D) aluminum alloy micro-fin arrays in the dielectric coolant HFE-7100. Results showed that the presence of 1D micro-fin arrays can significantly enhance pool boiling performance above that of a planar, unpatterned baseline surface but with important and sometimes nonintuitive dependence on micro-fin height. Experimental data indicated that a simple increase in surface area does not necessarily correlate to improved heat transfer performance, while high-speed imaging revealed that the presence of the micro-fins induces a periodic series of upward and downward flow patterns, in addition to distinct vapor bubble migration behavior. These results expand the range of surface types and working fluids for which spatially periodic and distinct liquid/vapor transport pathways created via microscale surface modification have been reported.