High Heat Flux Cooling Technologies Using Microchannel Evaporators: Fundamentals and Challenges

Abstract

Flow boiling in multi micro-channel evaporators is a promising approach to cooling high heat flux in many devices. Understanding of the fundamentals of flow boiling in multi microchannel evaporators is urgently needed. This paper presents a critical review on the research of flow boiling phenomena in microchannels. First, classifications of macro- and micro-channels are briefed. Then, studies on flow boiling in multi microchannels with plain surface are analyzed. Next, studies of flow boiling in multi microchannels with various enhanced technologies are analyzed. Finally, heat transfer mechanisms and development of prediction methods are discussed. According to the critical review and analysis of the current research on the fundamental issues and challenges of flow boiling in micro-channels, future research needs have been identified and recommended. In general, systematic, and accurate experimental data of flow boiling in micro-channels are needed by using advanced measurement technologies. In particular, optimal design of microchannel evaporators with plain surface and enhanced structures is lacking and should be investigated. The physical mechanisms of flow boiling should be further investigated based on the corresponding flow patterns. Furthermore, mechanistic prediction methods should be developed. Furthermore, systematic experimental, analytical and modeling studies on transient flow boiling phenomena in micro-channels should be conducted to understand the physical mechanisms and develop the theoretical models.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Lixin Cheng

Lixin Cheng has worked at Sheffield Hallam University since 2016. He obtained his Ph.D. in Thermal Energy Engineering at the State Key Laboratory of Multiphase Flow at Xi’an Jiaotong University, China in 1998. He has received several prestigious awards such as Alexander von Humboldt Fellowship in Germany in 2006, an ERCOFTAC Visitor Grant in Switzerland in 2010 and a Distinguished Visiting Professorship of the City of Beijing, China in 2015. His research interests are multiphase flow and heat transfer and thermal energy engineering. He has published more than 100 papers in journals and conferences, 9 book chapters and edited 10 books. He has delivered more than 60 keynote and invited lectures worldwide. He has been the chair of the World Congress on Momentum, Heat and Mass Transfer (MHMT) since 2017. He is one of the founders and co-chair of the International Symposium of Thermal-Fluid Dynamics (ISTFD) series since 2019. He is associate editor of Heat Transfer Engineering, Heat Transfer Research and Journal of Fluid Flow, Heat and Mass Transfer, and international advisor of Thermal Power Generation (a Chinese journal).

Guodong Xia

Guodong Xia is a leading professor in Thermal Energy Engineering at Beijing University of Technology, China. He received his Ph.D. in Thermal Energy Engineering at the State Key Laboratory of Multiphase Flow of Xi’an Jiaotong University, China in 1996. He was a visiting professor in the Institute of Process Engineering at the University of Hanover, Germany in 2000-2001. His research interests include fundamentals and applications of microscale heat transfer, multiphase flow and heat transfer, waste energy recovery, thermal energy system, heat exchanger design and enhanced heat transfer. He is a member of the multiphase flow committee of the Chinese Society of Engineering Thermophysics and a member of the multiphase flow committee of the Chinese Society of Theoretical and Applied Mechanics. He has published more than 150 papers in journals and conferences.