Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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Study of Pool Boiling Heat Transfer on Various Surfaces with Variation of Flow Velocity

다양한 표면에서 유동 속도에 따른 풀 비등 열전달에 관한 연구

  • Kang, Dong-Gyu (Dept. of Mechanical Engineering, Inha Univ.) ;
  • Lee, Yohan (Dept. of Mechanical Engineering, Inha Univ.) ;
  • Seo, Hoon (Dept. of Mechanical Engineering, Inha Univ.) ;
  • Jung, Dongsoo (Dept. of Mechanical Engineering, Inha Univ.)
  • 강동규 (인하대학교 기계공학부) ;
  • 이요한 (인하대학교 기계공학부) ;
  • 서훈 (인하대학교 기계공학부) ;
  • 정동수 (인하대학교 기계공학부)
  • Received : 2012.06.29
  • Accepted : 2013.01.16
  • Published : 2013.04.01
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Abstract

In this study, a smooth flat surface, low fin, Turbo-B, and Thermoexcel-E surfaces are used to examine the effect of the flow velocity on the pool boiling heat transfer coefficients (HTCs) and critical heat fluxes (CHFs). HTCs and CHFs are measured on a smooth square heater of $9.53{\times}9.53mm^2$ at $60^{\circ}C$ in a pool of pure water at various fluid velocities of 0, 0.1, 0.15, and 0.2 m/s. Test results show that for all surfaces, CHFs obtained with flow are higher than those obtained without flow. CHFs of the low fin surface are higher than those of the Turbo-B and Thermoexcel-E surfaces due largely to the increase in surface area and sufficient fin spaces for the easy removal of bubbles. CHFs of the low fin surface show even 5 times higher CHFs as compared to the plain surface. On the other hand, both Turbo-B and Thermoexcel-E surfaces do not show satisfactory results because their pore sizes are too small and water bubbles easily cover them. At low heat fluxes of less than $50kW/m^2$, HTCs increase as the flow velocity increases for all surfaces. In conclusion, a low fin geometry is good for application to steam generators in nuclear power plants.

본 연구에서는 열전달 표면의 형상과 그 위에서의 유동 속도의 변화에 따른 풀 비등 열전달계수의 변화를 살펴보기 위해 평판, 낮은 핀, Thermoexcel-E, Turbo-B 표면을 사용하여 유동 속도를 변화시켜가며 임계 열유속까지 열전달계수를 측정하였다. 작동 유체로는 증류수를 사용하였고 사각 평면 히터($9.53{\times}9.53mm$)를 이용하여 네 가지 표면에서 임계 열유속까지의 데이터를 얻을 수 있도록 장치를 제작하였고 $60^{\circ}C$에서 유동 속도를 0, 0.1, 0.15, 0.2m/s로 변화시켜가며 데이터를 취했다. 실험 데이터를 보면 모든 표면에서 유동이 있을 때의 임계 열유속은 유동이 없을 때에 비해 높은 것으로 나타났다. 또한 표면적의 증가와 기포 이탈에 충분한 핀 간격 등으로 인해 낮은 핀 표면의 임계 열유속은 평판이나 Turbo-B, Thermoexcel-E 표면보다 훨씬 놓았고 평판에 비해서는 무려 5배 정도의 향상을 보였다. 한편 대형 냉동기의 증발기용으로 개발된 Turbo-B와 Thermoexcel-E 표면은 물에서 기포의 이탈 지름이 크므로 열전달계수와 임계 열유속 모두 예상보다 큰 효과를 나타내지 않았다. $50kW/m^2$이하의 저열유속에서는 모든 표면에 대해 유동 속도 증가에 따라 열전달계수가 증가하였다. 결론적으로 핵발전소의 증기발생기에 적용하기에는 낮은 핀 형상의 표면이 가장 좋은 것으로 나타났다.

Keywords

References

  1. Jakob, M., 1949, "Heat Transfer," John Wiley & Sons, New York, pp. 636-638.
  2. Berenson, P. J., 1962, "Experiments on Pool Boiling Heat Transfer," Int. J. Heat and Mass Transfer, Vol. 5, pp. 985-999. https://doi.org/10.1016/0017-9310(62)90079-0
  3. Bankoff, S. G., 1959, "Entrapment of Gas in the Spreading of a Liquid over a Rough Surface," AIChE J., Vol. 4, No. 1, pp. 24-26.
  4. Myers, J. E. and Katz, D. L., 1953, "Boiling Coefficients outside Horizontal Tubes," Chem. Eng. Progr. Symp. Ser. 19, Vol. 49, No. 5, pp. 107-114.
  5. Hesse, G., 1973, "Heat Transfer in Nucleate Boiling Maximum Heat Flux and Transition Boiling," Int. J. Heat and Mass Transfer, Vol. 16, pp. 1611-1627. https://doi.org/10.1016/0017-9310(73)90188-9
  6. Haley, K. W. and Westwater, J. W., 1966, "Boiling Heat Transfer from Single Fins," Proc. 3rd Int. Heat Transfer Conf., Vol. 3, pp. 245-253.
  7. Fujie, K., Nakayama, W., Kuwahara, H. and Kakizaki, K., 1977, "Heat Transfer Wall for Boiling Liquids," U. S. Patent 4,060,125.
  8. Wolverine Tube, 1985, "Turbo-B an Improved Evaporator Tube," product bulletin.
  9. Webb, R. L. and Pais, C., 1992, "Nucleate Pool Boiling Data for Five Refrigerants on Plain, Integral-fin and Enhanced Tube Geometries," Int. J. Heat and Mass Transfer, Vol. 35, No. 8, pp. 1893-1904. https://doi.org/10.1016/0017-9310(92)90192-U
  10. Tatara, R.A. and Payvar, P., 2000, "Pool Boiling of Pure R134a from a Single Turbo-BII-HP Tube," Int. J. Heat and Mass Transfer, Vol. 43, pp. 2233-2236. https://doi.org/10.1016/S0017-9310(99)00294-X
  11. Park, J. S., Kim, J. G., Jung, D. and Kim, Y. I., 2001, "Pool Boiling Heat Transfer Coefficients of New Refrigerants on Various an Enhanced Tubes," Korea J. Air-Conditioning and Refrigeration Engineering, Vol. 13, No. 8, pp. 710-719.
  12. Jung, D. S., An, K. Y. and Park, J. S., 2004, "Nucleate Boiling Heat Transfer Coefficients of HCFC22,HFC134a, HFC125, and HFC32 on Various Enhanced Tubes," Int. J. Refrigeration, Vol. 27, pp. 202-206. https://doi.org/10.1016/S0140-7007(03)00124-5
  13. Kline, S. J. and McClintock, F. A., 1953, "Describing Uncertainties in Single-sample Experiments," Mechanical Engineer, Vol. 75, pp. 3-8.
  14. Lee, Y. H., Kang, D. G. and Jung, D. S., 2011, "Pool Boiling Heat Transfer Coefficients of Water Up to Critical Heat Flux on Enhanced Surfaces," SAREK, Vol. 23, No. 3, pp. 173-242.
  15. Zuber, N., 1958, "On Stability of Boiling Heat Transfer," ASME, Vol. 80, pp. 711-714.
  16. Zhang, H., Mudawar, I. and Hasan, M. M., 2002, "Experimental and Theoretical Study of Orientation Effects on Flow Boiling CHF," Int. J. Heat and Mass Transfer, Vol. 45, pp. 4463-4477. https://doi.org/10.1016/S0017-9310(02)00152-7
  17. Fritz, W. and Ende, W., 1936, "Uber den Verdam-Pfungsvorgang nach Kinematographischen Aufnahmen an Dampflasen," Phys. Zeitschr. Vol. 37, pp. 391-401.
  18. Dhir, V. K., Abarajith, H. S. and Li D., 2007, "Bubble Dynamics and Heat Transfer During Pool and Flow Boiling," Heat Transfer Engineering, Vol. 28, No. 7, pp. 608-624. https://doi.org/10.1080/01457630701266421
  19. Maity, S., 2000, "Effect of Velocity and Gravity on Bubble Dynamics," MS Thesis, University of California, Los Angeles, California, USA.