报告题目：Development of a Heat Sink with Ultra-high Performance
报 告 人：潘钦教授
报告时间：2023年4月11日 星期二上午9:00~11:00
报告地点：机械与汽车工程学院 宏生科技楼223室
欢迎广大师生踊跃参加。
机械与汽车工程学院
2023年4月4日
报告人简介：
Professor PAN Chin is CLP Power chair professor of nuclear engineering and head of the Department of Mechanical Engineering at City University of Hong Kong. Prior to joining CityU in February 2018, Prof. Pan was a faculty member of National Tsing Hua University (NTHU) in Taiwan for 32 years from associate professor to Tsing Hua distinguished professor. Prof. Pan had rich experiences in academic administration at NTHU. For examples, Prof. Pan serves as the chairman of the Department of Engineering and System Science of NTHU from February 2001 to January 2004 and the founding Director of the Center for Energy and Environmental Research from December 2003 to July 2008. Prof. Pan was the Dean of the College of Nuclear Science from August 2005 to July 2011. Prof. Pan’s research focuses on multi-phase flow and boiling heat transfer. He published a book entitled Boiling Heat Transfer and Two-phase Flow in Chinese in 2001 and has published more than 110 journal papers, for most of which serving as corresponding author, and about 140 conference proceeding papers or presentations.
潘钦教授是香港城市大学机械工程系主任及核子工程讲座教授。在2018年2月加入城大之前，潘教授曾在台湾清华大学任教32年，从副教授到清华大学特聘教授。潘教授在清华大学的学术管理方面有丰富的经验。例如，潘教授从2001年2月至2004年1月担任国立清华大学工程与系统科学系主任，从2003年12月至2008年7月担任能源与环境研究中心创始主任。 潘教授于2005年8月至2011年7月担任原子科学院院长。潘教授的研究重点是多相流和沸腾传热。他于2001年出版了《沸腾传热与两相流》一书，并发表了110多篇期刊论文，其中大部分是作为通讯作者，以及约140篇会议论文或报告。
报告摘要：
Boiling with proper bubble manipulation may significantly enhance performance in heat transfer as well as fluid flow. This talk will present our recent development of a Counter Flow Diverging Microchannel (CFDM) heat sink with ultra-high performance through an innovative and unique combination of diverging microchannels and counter-flow manifold, which enables extensive channel-to-channel heat transfer. Such a mechanism enhances nucleate boiling near the channel inlet with subcooled liquid flow, while it suppresses, even reduces, void growth near the channel exit. This may result in a void fraction distribution nearly uniform along the channel at high heat fluxes. Consequently, the critical heat flux may not take place near the end of the channel due to the dry out of liquid film and is significantly increased. Moreover, the two-phase flow pressure drop may not increase significantly with increase in heat flux. For a heat sink with a relatively large area of 3 cm×4 cm and under the limitation of wall temperature of about 140 ℃, a heat flux as high as 3525 kW/m2 is achieved without sign of reaching the critical heat flux for a relatively low mass flux of 600 kg/m2s of de-ionized water. A micro and nano structure on channel bottom surface significantly enhances the performance with heat flux greater than 400 W/cm2 without reaching the critical heat flux. The coefficient of performance, which is defined as the total heat dissipation rate to the pumping power, obtained is one order of magnitude higher than that reported in the literature. The experiments with smaller base area have demonstrated much higher performance. Such a large area and robust heat sink have great potential for broad applications such as cooling of inverters in the next generation electric vehicles and the first wall of a tokamak fusion reactor.
控制气泡扰动的沸腾，可以大大增强传热和流体流动的性能。本讲座将介绍最近开发的超高性能逆流分流微通道（CFDM）散热器，通过创新和独特的分流微通道和逆流歧管的组合，实现广泛的通道间热传递。这种机制通过过冷液体流动增强了通道入口附近的成核沸腾，抑制甚至减少了通道出口附近的空穴增长。这可能会导致在高热通量下沿着通道的空隙率几乎是均匀的。因此，由于液膜的干燥，临界热通量可能不会发生在通道的末端，而是明显增加。此外，两相流压降随着热通量的增加而并没有显著增加。面积为3 cm×4 cm的散热器在壁温约140℃的限制下，对于相对较低的质量流量为600 kg/m2s的去离子水，热通量为3525 kW/m2，没有达到临界热通量的迹象。通道底面采用微纳结构，热通量大于400 W/cm2时，性能显著提高，且未达到临界热通量。计算得到的性能系数（定义为泵送功率与总散热率之比）比文献中报道的要高一个数量级。较小基底面积的实验显示了更高的性能。如此一个大面积、坚固的散热器在下一代电动汽车逆变器的冷却、托卡马克核聚变反应堆的第一壁等领域有着巨大的应用潜力。
