Abstract
Boiling and condensation heat transfer have been extensively studied experimentally during the past century because of its high heat transfer rate for temperature control of energy conversion and power systems as well as cooling of electronic devices. In recent years, advances in micro-fabrication technology have enabled the use of micro-/nanostructured surfaces and modifications in surface wettability for the purpose of improving phase-change heat transfer performance in micro-heat exchangers for cooling of microelectronic chips. Recent experiments have shown that these interfacial effects can enhance nucleate boiling heat transfer in evaporators and facilitate condensate discharge in condensers. However, a fundamental understanding of mechanisms of enhanced phase-change heat transfer process cannot be fully understood from experimental investigations because of the complex physical processes involved. In spite of great advances made in the numerical simulation of two-phase isothermal flow based on traditional macroscopic CFD methods, simulations of boiling and condensation heat transfer processes with interfacial effects taken into consideration remain a most challenging task. Most recently, mesoscale numerical simulations based on lattice Boltzmann method have been developed to study effects of wettability and microstructures in boiling and condensation heat transfer phenomena. These mesoscale simulations have successfully predicted effects of wettability and microstructures on bubble nucleation at low heat flux, and on formation of vapor film and bubble columns at high heat flux leading to dryout and burnout of the heater. Effects of pitch and width of microcavities on bubble nucleation and boiling heat transfer are determined. Simulations of wettability effects on dropwise condensation heat transfer on subcooled surfaces based on the newly developed phase-change lattice Boltzmann method have also been carried out.
About the speaker
Prof Ping Cheng received his PhD in Aeronautics and Astronautics from Stanford University in 1965. He joined University of Hawaii as Associate Professor of Mechanical Engineering in 1970 and served as Chairman of the department from 1989 to 1994. From 1995 to 2002, he was appointed the second Head of Department of Mechanical Engineering at The Hong Kong University of Science and Technology.
Prof Cheng is a world-renowned researcher in the field of heat transfer with great and far-reaching contributions. He has published more than 230 SCI journal papers in radiative heat transfer, porous-media heat transfer and microscale heat transfer, and was listed as one of the world’s “Highly Cited Researchers” by Thomson Reuters in 2014. He was elected Fellow of The American Society of Mechanical Engineers (ASME) in 1986, and Fellow of The American Institute of Aeronautics and Astronautics (AIAA) in 2004. As a testament to his professional achievements, Prof Cheng has received numerous international top honors, including the 1996 ASME Heat Transfer Memorial Award and the 2006 ASME Heat Transfer Classic Paper Award for his research work in porous-media heat transfer, the 2003 AIAA Thermophysics Award for his research in radiative heat transfer, and the 2006 ASME/AIChE (The American Institute of Chemical Engineers) Max-Jakob Memorial Award, considered the highest international honor in the field of heat transfer. He was also the recipient of the 2006 Shanghai Science and Technology Award (First Class), and the 2007 State Natural Science Award (Second Class) for his research in microscale heat transfer. He was elected a member of Division of Technological Sciences in the Chinese Academy of Sciences (CAS) in 2011.
Prof Cheng is also very active in international heat transfer community, serving as an editor of Int. J. Heat & Mass Transfer, an editor of Int. Communications in Heat & Mass Transfer, and a member of editorial boards of 14 international heat transfer and energy journals. He will be chairing the 16th International Heat Transfer Conference in 2018, which will be held in China for the first time in its 67-year history.
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