Study of heat transfer enhancement for structured surfaces in spray cooling
Study of heat transfer enhancement for structured surfaces in spray cooling
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DOI：
10.1016/j.applthermaleng.2013.05.047
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发表时间：
2013-09
影响因子：
6.4
通讯作者：
J. Xie;Y. B. Tan;F. Duan;K. Ranjith;T. Wong;K. Toh;K. F. Choo;P. Chan
中科院分区：
文献类型：
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作者：
J. Xie;Y. B. Tan;F. Duan;K. Ranjith;T. Wong;K. Toh;K. F. Choo;P. Chan
通过实验研究了喷淋冷却中强化表面的换热效果。以R134a为工作流体，在闭环系统中测试了包括微观、宏观和多尺度结构形状在内的增强表面以及参考光滑平面。实验结果表明，对宏观结构表面的冷却性能起决定性作用的是翅片的排列，而不是简单的湿润面积的增加。微观结构的平面通过提供更多的潜在成核位置和毛细效应来促进成核沸腾。尽管具有相同的表面几何形状，但植入微观结构的多尺度结构表面在传热增强方面优于宏观结构表面。以光滑的平面为基准，微观结构平面的相对传热增强率为32%，而宏观结构表面的相对传热增强率为36%，而多尺度结构表面的相对传热增强率高达65%。除了提高传热性能外，宏观结构表面还具有其他优点，如延长过渡过程，减少电源关闭后加热器表面保持在极高温度状态（膜沸腾）的时间。
Experiments were conducted to study the heat transfer effects of enhanced surfaces in spray cooling. The enhanced surfaces including micro-, macro- and multiscale-structured shapes along with a referenced smooth flat surface were tested in a closed loop system with R134a as the working fluid. The experimental results indicate that fin arrangement rather than a simple increase in wetted area plays a decisive role in the cooling performance of macro-structured surfaces. The micro-structured flat surface was suggested to enhance nucleate boiling by providing more potential nucleation sites and capillary effects. Despite having the same surface geometries, multiscale-structured surfaces with planted micro-structures outperformed macro-structured surfaces in terms of heat transfer enhancement. Using the smooth flat surface as a baseline, the micro-structured flat surface produced a relative heat transfer enhancement of 32% compared to the 36% of the macro-structured surfaces, while the multiscale-structured surfaces achieved a heat transfer enhancement of up to 65%. In addition to improving heat transfer performance, macro-structured surfaces provide other advantages such as prolonging the transition process and reducing the period of time which the heater surface remains in the extremely high temperature regime (film boiling) after power is switched off.