Extraordinary boiling enhancement through micro-chimney effects in gradient porous micromeshes for high-power applications
Extraordinary boiling enhancement through micro-chimney effects in gradient porous micromeshes for high-power applications
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DOI：
10.1016/j.enconman.2020.112665
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发表时间：
2020-04
影响因子：
10.4
通讯作者：
Shiwei Zhang;Xingchi Jiang;Howard Y. Li;Gong Chen;Yalong Sun;Yong Tang;C. Pan
中科院分区：
文献类型：
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作者：
Shiwei Zhang;Xingchi Jiang;Howard Y. Li;Gong Chen;Yalong Sun;Yong Tang;C. Pan
工程表面的沸腾强化对于提高能源系统的效率和大功率电子设备的有效热管理具有根本的重要性。本研究开发了具有梯度孔隙率的高成本效益和超可扩展的铜多孔微网，以进一步最大限度地提高沸腾性能。一个独特的微烟囱效应的梯度网格，使越来越快的气泡在小直径的离开，被发现占上风，在整个核态沸腾。这种坚固的表面结构具有优异的临界热流密度，达到2719 kW/m2，同时具有261 kW/m2 K的传热系数，这上级优于大多数相关文献中获得的最大值。促进气泡动力学的分析和与分析模型的比较表明，由于简单的孔隙度调制的微烟囱效应是另一个重要的机制，以进一步提高沸腾能力。最后，作为一个潜在领域的例子，梯度微网格的核态沸腾显示出很大的优势，电池性能的浓缩比和浓缩光电池的电效率的提高。这项研究有望为更高效的相变器件提供高性能的表面改性，如流动沸腾微通道，沸水反应器和其他高功率热系统。
Boiling enhancement from engineering surfaces is of fundamental importance for efficiency enhancement of energy systems and effective thermal management of high-power electronics. The present study develops highly cost-effective and ultrascalable copper porous micromeshes with gradient porosity to further maximize the boiling performance holistically. A unique micro-chimney effect in the gradient meshes, enabling ever-faster bubble departure at small diameters, is revealed to prevail throughout the entire nucleate boiling. This robust surface structure presents an outstanding critical heat flux up to 2719 kW/m2simultaneously with ultrahigh heat transfer coefficient of 261 kW/m2K, which is superior to the maxima achieved in most relevant literatures. The analysis of facilitated bubble dynamics and comparison with an analytical model demonstrate that the micro-chimney effect due to simple porosity modulation is another significant mechanism to further enhance boiling capacity. Finally, as an example of potential areas, the nucleate boiling of gradient micromeshes exhibits great advantage of cell performance enhancement in concentrated ratio and electrical efficiency of concentrated photovoltaics. This study promises a high-performance surface modification for more efficient phase-change devices, such as flow boiling microchannels, boiling water reactors, and other high-power thermal systems.