Subcooled Pool Boiling on Hierarchical Micro- and Nanostructure-Modified Copper Surfaces in HFE-7100 Dielectric Liquid
Subcooled Pool Boiling on Hierarchical Micro- and Nanostructure-Modified Copper Surfaces in HFE-7100 Dielectric Liquid
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DOI：
10.1080/15567265.2023.2293710
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发表时间：
2023-12
影响因子：
4.1
通讯作者：
Shayan Davani;Bin Zhang;Brendon Doran;Luke Hansen;Mohammad Khan;Mahdi Roodbari;W. J. Meng;Arden L. Moore
中科院分区：
文献类型：
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作者：
Shayan Davani;Bin Zhang;Brendon Doran;Luke Hansen;Mohammad Khan;Mahdi Roodbari;W. J. Meng;Arden L. Moore
摘要包括微米尺度和纳米尺度结构的分级表面先前已经被研究作为针对多个长度尺度以实现上级池沸腾性能的手段。然而，先前的研究几乎完全集中在高表面张力工作流体上，而技术上重要的低表面张力流体在很大程度上仍未被开发。由于它们显著较低的表面张力，这些液体倾向于将捕获在加热表面的表面空腔中的空气推出，导致在低至中等过热下与水中的相同表面相比具有较少的成核位点。因此，为了克服这些性能限制并加速其采用，迫切需要开发用于电介质液体中池沸腾的有效表面改性技术并了解其背后的多相物理。在这项工作中，我们利用可扩展的制造技术，实现四个单独的表面类型（平面，纳米尺度改性，微米尺度改性，和分层）和实验确定其各自的池沸腾性能内的低表面张力商业工作流体HFE-7100。最大的传热增强125%，在38 K的温度下观察到的最佳性能的样品，有趣的是纳米改性，而不是那些层次型。通过高速视频分析的蒸汽气泡行为的视觉观察被用来解释基本的多相物理，为什么这些样品表现如此之好，以及未来的方向，实现跨多个长度尺度的表面优化。
ABSTRACT Hierarchical surfaces comprised both microscale and nanoscale structures have been previously studied as a means of targeting multiple length scales to achieve superior pool boiling performance. However, preceding studies have focused almost exclusively on high surface tension working fluids, while technologically important low surface tension fluids have remained largely unexplored. Due to their significantly lower surface tension these liquids tend to push out the air trapped in surface cavities of the heating surface, resulting in fewer nucleation sites compared to the same surface in water at low to moderate superheats. Thus, developing effective surface modification techniques for pool boiling in dielectric liquids and understanding the multiphase physics behind them is a pressing need in order to overcome these performance limitations and accelerate their adoption. In this work, we utilize scalable manufacturing techniques to realize four separate surface types (planar, nanoscale-modified, microscale-modified, and hierarchical) and experimentally determine their respective pool boiling performance within the low surface tension commercial working fluid HFE-7100. A maximum heat transfer enhancement of 125% at 38 K of superheat was observed for the best performing samples, which interestingly were nanoscale-modified and not those of the hierarchical type. Visual observations via high-speed video analysis of vapor bubble behavior are utilized to explain the underlying multiphase physics as to why these samples performed so well and future directions for achieving surface optimization across multiple length scales.