Improved two-phase flow boiling in a minichannel heat sink for thermal management of information and communication technology (ICT) equipment
Improved two-phase flow boiling in a minichannel heat sink for thermal management of information and communication technology (ICT) equipment
复制标题
DOI：
10.1016/j.applthermaleng.2020.115957
复制
发表时间：
2020-11
影响因子：
6.4
通讯作者：
Sihui Hong;C. Dang;E. Hihara;H. Sakamoto;Mizuki Wada
中科院分区：
文献类型：
--
作者：
Sihui Hong;C. Dang;E. Hihara;H. Sakamoto;Mizuki Wada
热管理系统在散热和保障设施安全方面发挥着重要作用。对于信息和通信技术(ICT)系统，高度可靠的运行依赖于准确的热控制，包括获得的最高温度和半导体器件的温度一致性。在文献中，两相流沸腾装置被认为是解决这一问题的有效解决方案；然而，由于流动沸腾的不稳定，这类装置的应用仍然面临着严重的挑战。本研究旨在解决工业CT系统中两相流不稳定引起的换热恶化问题。在前人提出的径向膨胀微通道散热器(REMHS)的基础上，测试了截断结构和缝隙结构对进一步稳定流动沸腾和强化换热性能的影响。在流动方向上采用截流结构，以缓解小通道内蒸汽段塞的快速膨胀。这使REMHS在高热流密度条件下的换热系数提高了近一倍，并有效地消除了散热器上的局部热点。在220kW/m2的热通量下，REMHS下游的过热温度从29K下降到13K，降幅为55%。此外，还获得了较好的壁温均匀度。间隙结构在将温度波动维持在0.6℃以下的汽液分离中被发现是有效的。通过使用这两种技术抑制有害的反向流动，REMHS在广泛的操作条件下实现了高流动沸腾换热能力，满足了ICT设备热管理系统的要求。
Thermal management systems play a significant role in dissipating heat and guaranteeing the safety of facilities. For information and communication technology (ICT) systems, a highly reliable operation depends on accurate thermal control, including the maximum temperature attained and the uniformity of temperature of the semiconductor devices. In the literature, two-phase flow boiling devices have been proposed as an efficient solution for addressing this concern; however, the application of such devices is still fraught with serious challenges owing to the unstable flow boiling. This study aims at solving the problem of undesired heat transfer deterioration triggered by two-phase flow instability in ICT systems. Based on our previous proposed radial expanding minichannel heat sink (REMHS), we tested the effects of a cut-off structure and a gap structure on further stabilizing the flow boiling and enhancing heat transfer performance. The cut-off structure is employed in the flow direction to relieve the rapid expansion of vapor slugs in the minichannels. This elevated the heat transfer coefficient of the REMHS by nearly two-fold under high heat flux conditions and effectively eliminated the local hotspot on the heat sink. The overheating at the downstream of the REMHS, in terms of temperature, decreased by 55% from 29 to 13 K at a heat flux of 220 kW/m2. Moreover, a better wall temperature uniformity was obtained. The gap structure was found effective in liquid–vapor separation that maintains the temperature fluctuations below 0.6 K. By suppressing the detrimental reversal flow with the two proposed techniques, the REMHS achieved a high flow boiling heat transfer capability over a wide range of operating conditions and met the requirement of the ICT equipment thermal management system.