DOI QR코드

DOI QR Code

높은 Pr 수의 유체를 사용한 수직 원형관 외부의 자연대류 실험

Experiments on Natural Convection on the Outer Surface of a Vertical Pipe by Using Fluids with High Pr Number

  • 투고 : 2010.05.19
  • 심사 : 2010.10.18
  • 발행 : 2011.01.01

초록

유사성 원리를 이용하여 매우 높은 Pr 수의 유체를 사용하여 수직 원형관 외부의 자연대류 열전달 현상을 실험적으로 연구하였다. 황산-황산구리 수용액의 전기도금계를 물질전달계로 채택하였으며, 실험은 직경 0.005m~0.035m의 음극을 사용하여 Pr 수 2,094~4,173 그리고 $Ra_H$$1.4{\times}10^9{\sim}4{\times}10^{13}$에서 열전달계수를 측정하였다. 층류에서 실험한 결과는 King, Jakob와 Linke, McAdams, Bottemanne의 수직 원형관 자연대류의 열전달 상관식에 일치하였고 난류에서는 수직평판 난류 자연대류 상관식인 Fouad의 상관식과 일치하였고 Pr 수에 대한 의존성이 나타났다. 실험을 통하여 도출한 층류 상관식은 $Nu_H=0.55Ra^{0.25}_H$,�㉢�류 상관식은 $Nu_H=0.12Ra^{0.28}_HPr^{0.1}$였다. 층류와 난류사이의 천이는 $Ra_H$ 수 약 $10^{12}$에서 발생하였다.

In this study, we investigated the natural convection on the outer surface of a vertical pipe by performing mass transfer experiments using fluids with high Pr number using the concept of analogy between heat and mass transfer. A cupric acid-copper sulfate electroplating system was adopted as the mass transfer system. Tests were performed for $Ra_H$ numbers from $1.4{\times}10^9$ to $4{\times}10^{13}$, Pr numbers from 2,094 to 4,173, and diameters from 0.005 m to 0.035 m. The test results for laminar flow conditions were in good agreement with the correlations reported by King, Jakob and Linke, McAdam, and Bottemanne, and those for turbulent conditions with the correlations presented by Fouad for a vertical plate and also proved the dependence on Pr numbers. The obtained correlations were $Nu_H=0.55Ra^{0.25}_H$ for laminar and $Nu_H=0.12Ra^{0.28}_HPr^{0.1}$ for turbulent. The transition between laminar and turbulent occurs at $Ra_H$ of about $10^{12}$.

키워드

참고문헌

  1. Bejan., A., 2003, Convection Heat Transfer, 3rd ed., John Wiley & Sons, INC, New York, pp. 207-222.
  2. Sparrow, E. M. and Gregg, J. L., 1955, "Laminar Free Convection Heat Transfer from the Outer Surface of a Vertical Circular Cylinder," Trans. ASME, Vol. 78, pp. 1823-1829. https://doi.org/10.1016/0017-9310(70)90155-9
  3. Ede, A. J., 1976, "Advances in Free Convection," Advance in Heat Transfer, Vol. 4, pp. 1-64. https://doi.org/10.1016/S0065-2717(08)70272-7
  4. Minkowycz, W. J. and Sparrow, E. M., 1974, "Local Nonsimilar Solution for Natural Convection on a Vertical Cylinder," Journal of Heat Transfer, Vol. 96, pp. 178-183. https://doi.org/10.1115/1.3450161
  5. Elenbass, W., 1948, "The Dissipation of Heat by Free Convection from Vertical and Horizontal Cylinders," Journal of Applied Physics, Vol. 19, pp. 1148-1154. https://doi.org/10.1063/1.1715035
  6. Lefevre., E. J., 1956, "Laminar Free Convection From a Vertical Plane Surface," 9th International Congress on Applied Mechanics, Brussels, pp.1-168.
  7. Fouad, M. G. and Ibl., N., 1960, "Natural Convection Mass Transfer at Vertical Electrodes Under Turbulent Flow Conditions," Electrochimica Acta, Vol. 3, pp. 233-243. https://doi.org/10.1016/0013-4686(60)85007-4
  8. Griffiths, E., and Davis, A. H., 1922, "The Transmission of Heat by Radiation and Convection," DSIR Food Investigation Board Special Report, London, Vol. 9.
  9. King, W. J., 1932, "The Basic Laws and Data of Teat Transmission," Mechanical Engineering, Vol. 54, pp. 347-353.
  10. Jakob, M. and Linke, W., "Warmeubergang Beim Verdampfen von Flussigkeiten an Senkrechten und Waagerechten Flaschen," Vol. 36, pp. 267-280.
  11. Eigenson, L. S., 1940, "Les Lois Gouvernam la Transmission de Chaleur aux Gaz Biatomique par les Parois Descylinder Verticaux Dans le cas de Convection Naturelle," Dokl. Akad. Nauk SSSR, Vol. 26, pp. 440-444.
  12. Touloukian, Y. S., Hawkins, G. A., and Jakob, M., 1948, "Heat Transfer by Free Convection from Heated Vertical Surfaces to Liquids," Trans. ASME, Vol. 70, pp. 13-18.
  13. McAdams, W. H., 1954, Heat Transmission, 3rd ed., McGrow-Hill, New York.
  14. Hanesian, D., and Kalish. R. L., 1970, "Heat Transfer by Natural Convection with Fluorocabon Gases," IEEE Trans. Parts, Mater. Package., Vol. 6, pp. 146-148. https://doi.org/10.1109/TPMP.1970.1136270
  15. Bottemanne, F. A., 1972, "Experimental Results of Pure and Simultaneous Heat and Mass Transfer by Free Convection About a Vertical Cylinder," Appl. Sci. Res., Vol. 25, pp. 372-382. https://doi.org/10.1007/BF00382310
  16. Carne, E. B., 1937, "Heat Loss by Natural Convection from Vertical Cylinders," Phil. Mag., Vol. 24, pp. 635-653.
  17. Bober, K., 2006, Natural Convection Heat Transfer from Vertical Cylinders, PhD Thesis, Poznan University of Technology, Poznan.
  18. Cebeci, T., 1974, "Laminar-Free-Convective-Heat Transfer from the Outer Surface of a Vertical Slender Circular Cylinder," in: Proceedings of the 5th International Heat Transfer Conference, vol. 3. Paper NC 1.4, Tokyo, pp. 15-19.
  19. E. J. Le Fevre and A. J. Ede, 1956, "Laminar Free Convection from the Outer Surface of a Vertical Circular Cylinder," in: Proceedings of the 9th International Congress Applied Mechanics, Vol. 4. Brussels, pp. 175-183.
  20. Pepiel, C. O., Wojtkowiak, J. and Bober, K., 2007, "Laminar Free Convective Heat Transfer from Isothermal Vertical Slender Cylinder," Int. J. Exp. Therm. Fluid Sci., Vol. 32, pp. 607-613. https://doi.org/10.1016/j.expthermflusci.2007.07.003
  21. Incropera, F. P. and Dewitt, D. P., 2003, Fundamentals of Heat and Mass Transfer, 5rd ed., Wiley, New York, pp. 399-401.
  22. Levich., V. G., 1962, Physicochemical Hydro-dynamics, Prentice-Hall, Englewood.
  23. Agar., J. N., 1947, "Diffusion and Convection at Electrodes," Discussion of Faraday Soc., 1, pp. 27-37.
  24. Selman, J. R. and Tobias., C. W., 1978, "Mass Transfer Measurement by the Limiting Current Technique," Adv. Chem. Eng. Vol. 10, pp. 211-318. https://doi.org/10.1016/S0065-2377(08)60134-9
  25. Fenech, E. J. and Tobias, C. W., 1960, Electrochim. Acta 2, 311. https://doi.org/10.1016/0013-4686(60)80027-8
  26. Ko, S.-H., Moon, D.-W. and Chung, B.-J., 2006, "Applications of Electroplating Method for Heat Transfer Studies Using Analogy Concept," Nuclear Engineering and Technology, Vol. 38, 251-258.
  27. Kang, K.-U. and Chung, B.-J., 2010, "The Effects of the Anode Size and Position on the Limiting Currents of Natural Convection Mass Transfer Experiments In A Vertical Pipe," Trans. of the KSME(B), Vol. 34, No. 1, pp. 1-8. https://doi.org/10.3795/KSME-B.2010.34.1.1
  28. Ko, B.-J. and Chung, B.-J., 2010, "Study on the Laminar Mixed Convection of Developing Flow in a Vertical Pipe," Trans. of the KSME(B), Vol. 34, No. 5. https://doi.org/10.3795/KSME-B.2010.34.5.481