U.S.-Japan Cooperative Research: Passive Control of Heat Transfer Performance in Reflux Condensers

这一奖项将使加州大学欧文分校的田长霖教授能够在两年的时间里与日本东京理工大学的Kunio Hijikata教授和其他日本研究人员合作。他们将研究影响被动控制设备性能的基本过程和机制，例如热管，这些设备基于逆流、两相回流冷凝运行。这种被动控制可以通过向热管工质中添加第二组分来实现；该组份可以是不凝结气体或用于控制冷凝的工质的二元混合物。我们将从分析和实验两方面研究控制气体分布以及热管系统整体性能的传热和传质机制。这项研究的目的是加深我们对控制热管性能的现象和类似机理的基本认识。对这些现象的充分了解可以刺激热管的使用，尽管热管在许多应用中比其他热传递方法具有相当大的优势，但热管的使用一直受到限制。为了实现这一目标，这位美国研究人员将分析含有不凝结气体的热管的传热性能。日本的合作者将对二元蒸汽混合物的热传递进行实验研究。通过比较分析和实验结果，研究人员将共同确定最有效的工作液组合。因此，这项研究利用了美国和日本调查人员互补的分析和实验技能。

This award will enable Prof. Chang-Lin Tien of the University of California, Irvine, to collaborate with Prof. Kunio Hijikata of the Tokyo Institute of Technology, Japan, and other Japanese researchers over a period of two years. They will investigate fundamental processes and mechanisms influencing the passive control of the performance of devices, such as heat pipes, which operate on the basis of counter-current, two-phase reflux condensation. Such passive control may be achieved by addition of a second component to the heat-pipe working fluid; this component might be a noncondensable gas or a binary mixture of working fluids to control the condensation. The heat and mass transfer mechanisms which control gas distribution, and hence overall performance of the heat-pipe system, will be investigated both analytically and experimentally. The purpose of this research is to enhance our basic understanding of the phenomena which control the performance of heat pipes and similar mechanisms. Adequate understanding of these phenomena could stimulate the use of heat pipes, which has been limited even though they offer considerable advantages over other heat-transfer methods in many applications. To achieve this objective the U.S. researcher will analyze the heat-trans- fer performance of heat pipes with noncondensable gases. Heat transfer with binary vapor mixtures will be investigated experimentally by the Japanese collaborator. By comparing the analytical and experimental results, the investigators will jointly determine the most effective combination of working fluids. This research thus utilizes the complementary analytical and experimental skills of the U.S. and Japanese investigators.