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http://dx.doi.org/10.3795/KSME-B.2008.32.8.612

Studies on the Evaporative Heat Transfer Characteristics and Pressure Drop of CO2 Flowing Upward in Inclined (45°) Smooth and Micro-fin Tubes  

Kim, Yong-Jin (서울대학교 기계항공공학부)
Cho, Jin-Min (서울대학교 기계항공공학부)
Kim, Min-Soo (서울대학교 기계항공공학부)
Publication Information
Transactions of the Korean Society of Mechanical Engineers B / v.32, no.8, 2008 , pp. 612-620 More about this Journal
Abstract
New alternative refrigerants have been developed due to the ozone layer depletion and global warming. For this reason, carbon dioxide is believed to be a promising refrigerant for use in air conditioners and heat pumps. Evaporative heat transfer characteristics and pressure drop of $CO_2$ with outer diameter of 5 mm in inclined ($45^{\circ}$) smooth and micro-fin tubes have been investigated by the experiments with respect to several test conditions such as mass fluxes, heat fluxes, evaporation temperatures in this study. The inclined ($45^{\circ}$) smooth and micro-fin tubes with length of 1.44 m were installed to measure the evaporative heat transfer coefficients of $CO_2$ and heat was supplied to the refrigerant by direct heating method where the test tube was uniformly heated by electricity. The tests were conducted at mass fluxes from 212 to $656\;kg/m^2s$, heat fluxes from 15 to $60\;kW/m^2$ and evaporation temperatures from -10 to $20^{\circ}C$. The heat transfer coefficients of $CO_2$ are slightly increased with increasing mass flux, and the heat transfer characteristics in the inclined ($45^{\circ}$) tubes are enhanced about $5{\sim}10%$ compared with those in horizontal or vertical tubes.
Keywords
Evaporation$CO_2$; Heat Transfer Coefficient; Smooth Tube; Micro-fin tube; Pressure Drop;
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Times Cited By KSCI : 1  (Citation Analysis)
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1 Cho, J. M. and Kim, M. S., 2007, "Experimental Studies on the Evaporative Heat Transfer and Pressure Drop of $CO_2$ in Smooth and Micro-fin Tubes of the Diameter of 5 mm and 9.52 mm," Int. J. Refrig., Vol. 30, pp. 986-994   DOI   ScienceOn
2 Lemmon, E. W., McLinden, M. O., and Huber, M. L. 2002, Reference Fluid Thermodynamic and Transport Properties (PEFPROP), NIST Standard Reference Database 23, Version 7.0, National Institute of Standards and Technology, Maryland, USA
3 Gnielinski, V., 1976, "New Equations for Heat and Mass Transfer in Turbulent Pipe and Channel Flow," Int. Chem. Eng., Vol. 16, pp. 359-368
4 Cho, J. M., Kim, Y. J. and Kim, M. S., 2008, "Experimental Studies on the Evaporative Heat Transfer Characteristics of $CO_2$/Propane Mixtures in Horizontal Smooth and Micro-fin Tubes," KSME International Journal, In press, Accepted Manuscript   DOI
5 Yoon, S. H., Cho, E. S., Hwang, Y. W., Kim, M. S., Min, K. D. and Kim, Y. C., 2004, "Characteristics of Evaporative Heat Transfer and Pressure Drop of Carbon Dioxide and Correlation Development," Int. J. Refrig., Vol. 27, pp. 111-119   DOI   ScienceOn
6 Kim, Y. J., Cho, J. M. and Kim, M. S., 2007, "Experimental Study on the Evaporative Heat Transfer and Pressure Drop of $CO_2$ Flowing Upward in Vertical Smooth and Micro-fin Tubes with the Diamter of 5 mm," Int. J. Refrig., In press, Accepted Manuscript
7 Kim, Y. C., Seo, K. J. and Chung, J. T., 2002, "Evaporation Heat Transfer Characteristics of R-410A in 7 and 9.52 mm Smooth/Micro-fin Tubes," Int. J. Refrig., Vol. 25, pp. 716-773   DOI   ScienceOn
8 Kuo, C. S. and Wang, C. C., 1996, "In-tube Evaporation of HCFC-22 in a 9.52 mm Micro- fin/Smooth Tube," Int. J. Heat and Mass Transfer, Vol. 39, pp. 2559-2569   DOI   ScienceOn
9 Carew, P. S., Thomas, N. H., and Johnson, A. B., 1995, A Physically Based on Correlation for the Effects of Power Law Rhelogy and Inclination on Slug Bubble Rise Velocity, Int. J. Multiphase Flow, Vol. 21, pp. 1091-1106   DOI   ScienceOn
10 Kim, Y. J., Jang, J., Hrnjak, P. S. and Kim, M. S., 2003, "An Experimental Study on Condensation Heat transfer of CO2 at Low Temperature in Smooth and Micro-fin Tubes," Proceeding of the SAREK Winter Annual Conference, pp. 50-55