Enhanced pool boiling heat transfer mechanisms for selectively sintered open microchannels
Enhanced pool boiling heat transfer mechanisms for selectively sintered open microchannels
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DOI：
10.1016/j.ijheatmasstransfer.2015.04.100
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发表时间：
2015-09-01
影响因子：
5.2
通讯作者：
Kandlikar, Satish G.
中科院分区：
文献类型：
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作者：
Jaikumar, Arvind;Kandlikar, Satish G.
池沸腾性能可以通过选择性地涂覆传热表面的不同区域来产生单独的液体蒸气路径而显著增强。在本文中，通过在通道宽度为762 μ m，通道深度为400 μ m，翅片宽度为200 μ m的开放式微通道上沉积多孔涂层来探索传热机理。在以下三个表面上用烧结多孔涂层制造：（i）整个微通道表面（烧结贯穿），（ii）仅翅片顶部（烧结翅片顶部），和（iii）仅通道壁（烧结通道）。实验测定了它们与脱气水在常压下的池沸腾性能。在7.5摄氏度的壁面温度下，获得了313 W/cm（2）的临界热通量（CHF），其中，与普通芯片相比，CHF提高了2.4倍。最高的热传递系数（HTC）的565千瓦/米（2）摄氏度，获得了这个表面转化为6.5倍的增强相比，一个平面表面。确定了三种增强机制：（i）面积增大的增强成核，（ii）气泡诱导的液体射流增强-类型-1和（iii）气泡诱导的液体射流增强类型-2。这些机制是负责增强HTC和CHF的烧结贯穿，烧结鳍顶和烧结通道，分别。尽管当前的测试表明烧结贯穿表面为选定的微通道尺寸提供了最高的CHF和FITC增强，但是改变微通道尺寸预计会影响这些配置的相对优点，因为液体和蒸气流动机制以根本不同的方式受到影响。(C)2015爱思唯尔有限公司版权所有。
Pool boiling performance can be enhanced significantly by generating separate liquid vapor pathways through selectively coating different regions of a heat transfer surface. In this paper, heat transfer mechanisms are explored by depositing porous coatings on an open microchannel with channel width 762 mu m, channel depth 400 mu m and fin width 200 mu m. Three surfaces were fabricated with sintered porous coatings on: (i) entire microchannel surface (sintered-throughout), (ii) only the fin tops (sintered-fin-top), and (iii) only the channel walls (sintered-channel). Their pool boiling performance with degassed water at atmospheric pressure was experimentally obtained. A critical heat flux (CHF) of 313 W/cm(2) at a wall superheat of 7.5 degrees C was obtained for a sintered-throughout surface with a 2.4 fold enhancement in CHF over a plain chip. Highest heat transfer coefficient (HTC) of 565 kW/m(2) degrees C was obtained for this surface which translated into a 6.5 fold enhancement when compared to a plain surface. Three enhancement mechanisms were identified: (i) Area Augmented Enhanced Nucleation, (ii) Bubble Induced Liquid Jet Enhancement - Type-1 and (iii) Bubble Induced Liquid jet Enhancement Type-2. These mechanisms were responsible for the enhancement in HTC and CHF for sintered-throughout, sintered-fin-tops and sintered-channels, respectively. Although the current testing indicated the sintered-throughout surface to provide the highest CHF and FITC enhancement for the selected microchannel dimensions, changing the microchannel dimensions is expected to influence the relative merits of these configurations as the liquid and vapor flow mechanisms are influenced in fundamentally different ways. (C) 2015 Elsevier Ltd. All rights reserved.