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

该奖项将使加州大学欧文分校的田昌林教授能够与日本东京工业大学的国雄Hijikata教授以及其他日本研究人员在两年的时间内进行合作。他们将研究影响设备性能被动控制的基本过程和机制，如热管，它在逆流、两相回流冷凝的基础上运行。这种被动控制可以通过在热管工作流体中添加第二组分来实现；该组分可以是不可冷凝气体或控制冷凝的工作流体的二元混合物。控制气体分布的传热和传质机制，从而控制热管系统的整体性能，将进行分析和实验研究。本研究的目的是加强我们对控制热管性能的现象和类似机制的基本认识。充分了解这些现象可以刺激热管的使用，尽管热管在许多应用中比其他传热方法具有相当大的优势，但热管的使用受到限制。为了实现这一目标，美国研究人员将分析带有不凝性气体的热管的传热性能。日本合作者将对二元蒸汽混合物的传热进行实验研究。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流体组合。因此，这项研究利用了美国和日本研究人员的互补分析和实验技能。

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.