Single-phase ambient and cryogenic temperature heat transfer coefficients in microchannels

Cryogenic Engineering Conference 2015

材料科学;物理学

Baek, S.^1 ; Bradley, P.E.^1

Material Measurement Laboratory, National Institute of Standards and Technology, Boulder

CO

80305, United States^1

关键词: Circular microchannel;    Conventional theory;    Cryogenic temperatures;    Heat transfer characteristics;    Heat transfer coefficient measurement;    Hydraulic diameter;    Low reynolds flow;    Single phase heat transfers;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/101/1/012005/pdf
DOI  :  10.1088/1757-899X/101/1/012005

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Micro-scaling cryogenic refrigerators, in particular the Joule-Thomson (JT) variety require very good information about heat transfer characteristics of the refrigerants flowing in the microchannels for optimal design and performance. The extremely low Reynolds flow is present in a micro JT cryocooler, the heat transfer characteristics at these conditions require investigation. There are numerous studies regarding heat transfer coefficient measurements of liquid flow in microchannels at/near ambient temperature and high Reynolds flow (Re>2000), that agree well with the conventional correlations. However, results from previous studies of gaseous flow in microchannels at low Reynolds flow (Re1000) follow conventional theory. The detailed experiment, procedure, and measured results are presented in this paper and discussed regarding deviation from ideal theory at low Reynolds flow.