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The experimental study on the boiling bubble behaviors and heat transfer performance of the deionized water across various pin fins
Heat and Mass Transfer ( IF 2.2 ) Pub Date : 2021-03-20 , DOI: 10.1007/s00231-021-03052-7
Junye Hua , Wenxin Hou , Gui Li , Luwen Qin , Dong Li , Xiaobao Zhao

Microchannel heat sink is widely utilized as one of the effective heat dissipation methods with lower heat transfer temperature difference. In this paper, visual experiment study has been conducted to focus on the inner relationship between heat transfer/flow properties in macroscopic aspect with bubble dynamic characteristics in microcosmic aspect. Results show that along with the increases of Re, the value of convective heat transfer coefficient(h) increases as well. Correspondingly, the pressure drops show a tendency as increasing, decreasing lately, then increasing again. The bubbles in the undergo the same four process: film boiling process, transition process from film to nucleate boiling zone, nucleate boiling process and single-phase convection process. And the variation of pressure drop is one-to-one correspondence with the four heat transfer process. Besides, the triangle pin fin holds the higher heat transfer coefficient, which may be explained from the quantities and the sequence of appearance of bubbles in nucleate heat transfer process. The migration diameter as well as coverage rate of bubbles appears the tendency as ascending firstly then down lately with the increase of Re, which fit the conclusion in macroscopic aspect in heat transfer/flow properties. It could be found that the migration size is mainly influenced by the flow rate as well as the density of bubbles. In this way, the position of bubble occurred is the key point effecting bubble growth time and growth radium. Three zones have been divided to summarize the dynamic behaviors of bubbles in different positions: The migration diameter of bubbles in Zone I in the biggest, with that in Zone II moderate and that in Zone II lowest. The tail of pin fin (Zone I) makes the bubbles more easily to merge the surrounding new nucleated small bubbles to a bigger size, with more residence time to leave the bubble growing bigger. The general growth size of bubbles in ellipse pin fin is smallest, around 0.08 mm and with growth cycle short as 0.616 s. Simultaneously, that of the triangle one is biggest, with the size as 0.099 mm and growth time as 2.112 s.



中文翻译:

去离子水在不同针状翅片上的沸腾行为和传热性能的实验研究

微通道散热器被广泛用作具有较低传热温度差的有效散热方法之一。本文进行了视觉实验研究,着眼于宏观方面的传热/流动特性与微观方面的气泡动力学特性之间的内在联系。结果表明,随着Re的增加,对流换热系数(h)也增加了。相应地,压降显示出增加的趋势,最近减少,然后再次增加。气泡经过相同的四个过程:薄膜沸腾过程,从薄膜到成核沸腾区的过渡过程,成核沸腾过程和单相对流过程。并且压降的变化与四个传热过程是一一对应的。此外,三角形销翅片具有较高的传热系数,这可以从成核传热过程中气泡的数量和出现顺序来解释。随着Re的增加,迁移直径和气泡覆盖率呈现先上升后下降的趋势。,这在宏观方面符合热传递/流动特性的结论。可以发现,迁移的大小主要受流速以及气泡密度的影响。这样,气泡发生的位置是影响气泡生长时间和镭生长的关键。划分了三个区域,总结了气泡在不同位置的动力学行为:第一区域中气泡的迁移直径最大,第二区域中气泡的迁移直径最小,第二区域中气泡的迁移直径最小。鳍鳍的尾部(I区)使气泡更容易将周围的新有核小气泡合并为更大的尺寸,并留有更多的停留时间,使气泡变得更大。椭圆形针状鳍片中气泡的一般生长尺寸最小,约为0.08 mm,生长周期短至0.616 s。同时,

更新日期:2021-03-21
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