Flow boiling in microchannels: Fundamentals and applications
Flow boiling in microchannels: Fundamentals and applications
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DOI：
10.1016/j.applthermaleng.2016.08.063
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发表时间：
2017-03-25
影响因子：
6.4
通讯作者：
Mahmoud, M. M.
中科院分区：
文献类型：
--
作者：
Karayiannis, T. G.;Mahmoud, M. M.
电子设备和高功率设备在性能和小型化方面的快速进步导致了巨大的热流量值，这些热流值需要有效地分散。计算机芯片的平均热流密度预计为2-4.5 mW/m(2)，局部热区为12-45min/m(2)，而在IGBT模块中，芯片级的热流密度可达到6.5-50 mW/m(2)。微通道内的流动沸腾由于能够在表面温度变化很小的情况下获得很高的换热速率，是这些器件和类似器件最有前途的冷却方法之一。然而，几个基本问题仍然不被理解，这阻碍了从实验室研究向商业应用的过渡。本文首先讨论了流动沸腾在微通道中的可能应用，以突出每种应用在热管理方面的挑战。在这一部分，还对采用微通道的不同集成系统进行了比较。比较表明，带有液体泵的微型制冷系统比微型蒸汽压缩制冷系统效率更高。本文介绍了单管和矩形多通道内流动沸腾的实验研究，讨论了以下基本问题：(1)微通道的定义，(2)流型和换热机理，(3)流动的不稳定性和反转及其对换热速率的影响，(4)通道表面特性的影响和(5)临界热流密度的预测。此外，本文还提出了用于预测小直径、小直径和微细管内流型转变边界和换热系数的关联式。(C)2016年提交人。爱思唯尔有限公司出版。
The rapid advances in performance and miniaturization of electronics and high power devices resulted in huge heat flux values that need to be dissipated effectively. The average heat flux in computer chips is expected to reach 2-4.5 MW/m(2) with local hot spots 12-45 MIN/m(2) while in IGBT modules, the heat flux at the chip level can reach 6.5-50 MW/m(2). Flow boiling in microchannels is one of the most promising cooling methods for these and similar devices due to the capability of achieving very high heat transfer rates with small variations in the surface temperature. However, several fundamental issues are still not understood and this hinders the transition from laboratory research to commercial applications. The present paper starts with a discussion of the possible applications of flow boiling in microchannels in order to highlight the challenges in the thermal management for each application. In this part, the different integrated systems using microchannels were also compared. The comparison demonstrated that miniature cooling systems with a liquid pump were found to be more efficient than miniature vapour compression refrigeration systems. The paper then presents experimental research on flow boiling in single tubes and rectangular multichannels to discuss the following fundamental issues: (1) the definition of microchannel, (2) flow patterns and heat transfer mechanisms, (3) flow instability and reversal and their effect on heat transfer rates, (4) effect of channel surface characteristics and (5) prediction of critical heat flux.Areas where more research is needed were clearly mentioned. In addition, correlations for the prediction of the flow pattern transition boundaries and heat transfer coefficients in small to mini/micro diameter tubes were developed recently by the authors and presented in this paper. (C) 2016 The Authors. Published by Elsevier Ltd.