Evaporating Heat Transfer Characteristics of R-l34a in a Horizontal Smooth Channel

  • Pamitran, A.S. (Graduate School, Department of Refrigeration Engineering, Chonnam National University) ;
  • Choi, Kwang-Il (Graduate School, Department of Refrigeration Engineering, Chonnam National University) ;
  • Oh, Jong-Taek (Department of Refrigeration Engineering, Chonnam National University) ;
  • Oh, Hoo-Kyu (Department of Refrigeration and A/C Engineering, Pukyong National University)
  • 발행 : 2006.12.10


Convective boiling heat transfer coefficients were measured in a horizontal minichannel with R-l34a. The test section was made of stainless steel tube with an inner diameter of 3.0 mm and a length of 2m. It was uniformly heated by applying electric current directly to the tube. Local heat transfer coefficients were obtained for heat fluxes from 10 to $40kW/m^2$, mass fluxes from 200 to $600kgT/m^2s$, qualities up to 1.0, and the inlet saturation temperature of $10^{\circ}C$. The experimental results were mapped on Wojtan et $al.'s^(7)$ and Wang et $al.'s^(8)$ flow pattern maps. The nucleate boiling was predominant at low vapor quality whereas the convective boiling was predominant at high vapor quality. Laminar flow appeared in the flow with minichannel. The experimental results were compared with six existing two-phase heat transfer coefficient correlations. A new boiling heat transfer coefficient correlation based on the superposition model for refrigerants was developed with mean and average deviations of 10.39% and -3.66%, respectively.



  1. Wattelet, J. P., Chato, J. C., Souza, A. L. and Christoffersen, B. R., 1994, Evaporative characteristics of R-12, R-134a, and a mixture at low mass fluxes, ASHRAE Trans., 94-2-1, pp. 603-615
  2. Shah, M. M., 1982, Chart correlation for saturated boiling heat transfer: equations and further study, ASHRAE Trans., Vol. 88, pp. 185-196
  3. Tran, T. N., Wambsganss, M. W. and France, D. M, 1996, Small circular- and rectangularchannel boiling with two refrigerants, Int. J. Multiphase Flow, Vol. 22, No. 3, pp. 485-498 https://doi.org/10.1016/0301-9322(96)00002-X
  4. Jung, D. S., McLinden, M., Radermacher, R. and Didion, D., 1989, A study of flow boiling heat transfer with refrigerant mixtures, Int. J. Heat Mass Transfer, Vol. 32, No. 9, pp. 1751-1764 https://doi.org/10.1016/0017-9310(89)90057-4
  5. Gungor, K. E. and Winterton, H. S. 1987, Simplified general correlation for saturated flow boiling and comparisons of correlations with data, Chem. Eng. Res., Vol. 65, pp. 148-156
  6. Kandlikar, S. G. and Steinke, M. E., 2003, Predicting heat transfer during flow boiling in minichannels and microchannels, ASHRAE Trans., CH-03-13-1, pp.667-676
  7. Wojtan, L., Ursenbacher, T. and Thome, J. R, 2005, Investigation of flow boiling in horizontal tubes: Part I - A new diabatic two-phase flow pattern map, Int. J. Heat and Mass Transfer, Vol. 48, pp. 2955-2969 https://doi.org/10.1016/j.ijheatmasstransfer.2004.12.012
  8. Wang, C. C., Chiang, C. S. and Lu, D. C., 1997, Visual observation of two-phase flow pattern of R-22, R-134a, and R-407C in a 6.5-mm smooth tube, Experimental Thermal and Fluid Science, Vol. 15, pp. 395-405 https://doi.org/10.1016/S0894-1777(97)00007-1
  9. Kattan, N., Thome, J. R and Favrat, D., 1998, Flow boiling in horizontal tubes: Part 1 - Development of a diabatic two-phase flow pattern map, Journal of Heat Transfer, Vol. 120, pp. 140-147 https://doi.org/10.1115/1.2830037
  10. Steiner, D., 1993, Heat transfer to boiling saturated liquids, VDI-Warmeatlas (VDI Heat Atlas), Verein Deutcher Ingenieure, ed., VDI-Gessellschaft Verfahrenstechnik und Chemieinge- nieurwesen (GCV), Dusseldorf, Germany (J. W. Fullarton, translator)
  11. Kew, P. A. and Cornwell, K., 1997, Correlations for the prediction of boiling heat transfer in small-diameter channels, Applied Thermal Engineering, Vol. 17(8-10), pp. 705-715 https://doi.org/10.1016/S1359-4311(96)00071-3
  12. Lazarek, G. M. and Black, S. H., 1982, Evaporative heat transfer, pressure drop and critical heat flux in a small diameter vertical tube with R-113, Int. J, Heat Mass Transfer, Vol. 25, pp. 945-960 https://doi.org/10.1016/0017-9310(82)90070-9
  13. Wambsganss, M. W., France, D. M., Jendrzejczyk, J. A. and Tran, T. N., 1993, Boiling heat transfer in a horizontal small-diameter tube, Journal of Heat Transfer, Vol. 115, pp. 963-975 https://doi.org/10.1115/1.2911393
  14. Bao, Z. Y., Fletcher, D. F. and Haynes, B. S., 2000, Flow boiling heat transfer of freon R11 and HCFC123 in narrow passages, Int. J, Heat and Mass Transfer, Vol. 43, pp. 3347-3358 https://doi.org/10.1016/S0017-9310(99)00379-8
  15. Pamitran, A. S., Choi, K. I., Oh, J, T. and Oh, H. K, 2006, Forced convective boiling heat transfer of R-410A in horizontal minichannels, Int. J, Refrigeration, In-Press
  16. Chen, J. C., 1966, A correlation for boiling heat transfer to saturated fluids in convective flow, Industrial and Engineering Chemistry, Process Design and Development, Vol. 5, pp. 322-329 https://doi.org/10.1021/i260019a023
  17. Zhang, W, Hibiki, T. and Mishima, K., 2004, Correlation for flow boiling heat transfer in mini-channels, Int. J. Heat and Mass Transfer, Vol. 47, pp. 5749-5763 https://doi.org/10.1016/j.ijheatmasstransfer.2004.07.034
  18. Chisholm, D., 1967, A theoretical basis for the Lockhart-Martinelli correlation for twophase flow, Int. J. Heat Mass Transfer, Vol. 10, pp. 1767-1778 https://doi.org/10.1016/0017-9310(67)90047-6
  19. Cooper, M. G., 1984, Heat flow rates in saturated nucleate pool boiling-a wide-ranging examination using reduced properties, In: Advances in Heat Transfer, Academic Press, Vol. 16, pp. 157-239
  20. Jung, D., Kim, Y., Ko, Y. and Song, K., 2003, Nucleate boiling heat transfer coefficients of pure halogenated refrigerants, Int. J. Refrigeration, Vol. 26, pp. 240-248 https://doi.org/10.1016/S0140-7007(02)00040-3