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

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지
DOI QR코드

DOI QR Code

Condensation Heat Transfer and Pressure Drop in Flat Tubes with Different Aspect Ratios

종횡비가 다른 납작관 내 응축열전달 및 압력손실

  • Kim, Nae-Hyun (Dept. of Mechanical System Engineering, Univ. of Incheon) ;
  • Park, Ji-Hoon (Dept. of Mechanical System Engineering, Univ. of Incheon) ;
  • Cha, Sang-Jin (Dept. of Mechanical System Engineering, Univ. of Incheon)
  • 김내현 (인천대학교 기계시스템공학부) ;
  • 박지훈 (인천대학교 기계시스템공학부) ;
  • 차상진 (인천대학교 기계시스템공학부)
  • Received : 2010.07.29
  • Accepted : 2010.09.27
  • Published : 2010.12.01
Download PDF
⟨ Previous Next ⟩

Abstract

In this study, condensation heat transfer coefficients of R-410A were obtained in flattened tubes made from round tubes with an inner diameter of 5.0 mm. The saturation temperature was $45^{\circ}C$; the heat flux, 10 kW/$m^2K$; the mass flux, 100-400 kg/$m^2s$; and the quality, 0.2-0.8. The results showed that the effect of the aspect ratio on the condensation heat transfer coefficient depended on the flow pattern. For annular flow, the heat transfer coefficient increased as the aspect ratio increased. For stratified flow, however, the reverse was true: the pressure drop increased as the aspect ratio increased. Existing correlations adequately predicted the heat transfer coefficients and pressure drops of the flattened tubes.

본 연구에서는 내경 5.0mm 원관을 납작하게 한 납작관에 대하여 R-410A 를 사용하여 응축열전달 실험을 수행하였다. 실험은 포화온도와 열유속을 각각 $45^{\circ}C$ 와 10kW/$m^2$으로 고정한 상태에서 질량유속과 건도를 변화시키며 수행되었다. 실험결과 납작관의 종횡비가 열전달계수에 미치는 영향은 유동양식에 따라 달리 나타났다. 환상류에서는 종횡비가 증가할수록 증가하고 성층류에서는 종횡비가 증가할수록 감소하였다. 한편 납작관의 마찰손실은 종횡비가 증가할수록 증가하였다. 기존 상관식들은 납작관의 열전달계수와 마찰계수를 적절히 예측하였다.

Keywords

References

  1. Webb, R. L. and Iyengar, A., 2001, “Oval Finned Tube Condenser and Design Pressure Limits,” J. Enhanced Heat Transfer, Vol. 8, pp. 147-158. https://doi.org/10.1615/JEnhHeatTransf.v8.i3.20
  2. Kim, N.-H. and Kim, S.-H., 2010, “Dry and Wet Air- Side Performance of a Louver-Finned Heat Exchanger Having Flat Tubes,” Journal of Mechanical Science and Technology, Vol. 24, pp. 1553-1561. https://doi.org/10.1007/s12206-010-0409-1
  3. Collier, J. G. and Thome, J. R., 1994, Convective Boiling and Condensation, 3rd edition, Oxford University Press.
  4. Ghiaansiaan, M. S., 2008, Two-Phase Boiling and Condensation in Conventional and Miniature Systems, Cambridge University Press.
  5. Wilson, M. J., Newell, T. A., Chato, J. C. and Infante Ferreira, C. A., 2003, “Refrigerant Charge, Pressure Drop, and Condensation Heat Transfer in Flattened Tubes,” Int. J. Refrigeration, Vol. 26, pp. 442-451. https://doi.org/10.1016/S0140-7007(02)00157-3
  6. Kim, M.-H., Shin, J. S. and Bullard, C. W., 2001, “Heat Transfer and Pressure Drop Characteristics during R-22 Evaporation in an Oval Microfin Tube,” J. Heat Transfer, Vol. 123, pp. 301-308. https://doi.org/10.1115/1.1351894
  7. Moreno Quiben, J., Cheng, L., da Silva Lima, R. J. and Thome, J. R., 2009, “Flow Boiling in Horizontal Flatten Tubes: Part I – Two-Phase Frictional Pressure Drop Results and Model,” Int . J. Heat Mass Transfer, Vol. 52, pp. 3634-3644. https://doi.org/10.1016/j.ijheatmasstransfer.2008.12.032
  8. Moreno Quiben, J., Cheng, L., da Silva Lima, R. J. and Thome, J. R., 2009, “Flow Boiling in Horizontal Flatten Tubes: Part II – Flow Boiling Heat Transfer Results and Model,” Int . J. Heat Mass Transfer, Vol. 52, pp. 3645-3653. https://doi.org/10.1016/j.ijheatmasstransfer.2008.12.033
  9. Nasr, M., Akhavan-Behabadi, M. A. and Marashi, S. E., 2010, “Performance evaluation of flattened tube in boiling heat transfer enhancement and its effect on pressure drop,” Int. Comm. Heat Mass Transfer, Vol. 37, pp. 430-436. https://doi.org/10.1016/j.icheatmasstransfer.2009.11.011
  10. ANSYS 12, 2010, ANSYS Inc.,
  11. Kim, N.-H., Cho, J.-P. and Youn, B., 2003, “Condensation of R-22 and R-410A in Flat Aluminum Extruded Tubes,” Int. J. Refrigeration, Vol. 26, pp. 830-839. https://doi.org/10.1016/S0140-7007(03)00049-5
  12. Wilson, E. E., 1915, “A Basis for Rational Design of Heat Transfer Apparatus,” Trans. ASME, Vol. 37, pp. 47-70.
  13. Kline S. J. and McClintock, F. A., 1953, “The Description of Uncertainties in Single Sample Experiments,” Mechanical Engineering, Vol. 75, pp. 3-9.
  14. Webb, R. L. and Kim, N. H., 2005, Principles and Enhanced Heat Transfer, Ch. 12, 2nd edition, Taylor and Francis Pub.
  15. Taitel, Y. and Dukler, A. E., 1976, “A Model for Predicting Flow Regime Transitions in Horizontal and Near Horizontal Gas-Liquid Flow,” AIChE J., Vol. 22, pp. 47-55. https://doi.org/10.1002/aic.690220105
  16. Friedel, L., 1979, “Improved Pressure Drop Correlations for Horizontal and Vertical Two-Phase Pipe Flow,” 3R Int., Vol. 18, pp. 485-492.

Cited by

  1. Effect of Aspect Ratio of Flat Tube on R410A Evaporation Heat Transfer and Pressure Drop vol.37, pp.4, 2013, https://doi.org/10.3795/KSME-B.2013.37.4.395