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Microscale Heat Transfer at Low Temperatures



Ray Radebaugh


This paper discusses the fundamentals and applications of heat transfer in small space and time domains at low temperatures. The modern trend toward miniaturization of devices requires a better understanding of heat transfer phenomena in small dimensions. In regenerative thermal systems, such as thermoacoustic, Stirling, and pulse tube refrigerators, miniaturization is often accompanied by increased operating frequencies. Thus, this paper also covers heat transfer in small time domains involved with possible frequencies up to several hundred hertz. Simple analytical techniques are discussed for the optimization of heat exchanger and regenerator geometry at all temperatures. The results show that the optimum hydraulic diameters can become much less than 100 ¿m at cryogenic temperatures, although slip flow is seldom a problem. The cooling of superconducting or other electronic devices in Micro-Electro-Mechanical systems (MEMS) requires a better understanding of the heat transfer issues in very small sizes. Space applications also benefit from a reduction in the size of cryocoolers, which has brought about considerable interest in microscale heat exchangers. Some recent developments in miniature heat exchangers for Joule-Thomson and Brayton cycle cryocoolers are discussed. Both single-phase and two-phase heat transfer are covered in the paper, but the emphasis is on single-phase gas flow. Some discussion of fabrication techniques is also included.
Microscale Heat Transfer Fundamentals and Applications
Publisher Info
Springer Science+Business Media LLC , New York, NY


cryocoolers, cryogenics, heat exchangers, high frequency, optimization, refrigeration, regenerators


Radebaugh, R. (2005), Microscale Heat Transfer at Low Temperatures, Microscale Heat Transfer Fundamentals and Applications, Springer Science+Business Media LLC , New York, NY, [online], (Accessed June 13, 2024)


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Created September 26, 2005, Updated November 10, 2018