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Effect of Oil on Pool Boiling of Refrigerant on Enhanced Tubes having Different Pore Sizes  

Kim Nae-Huyn (Department of Mechanical Engineering, University of Incheon)
Lee Eung-Ryul (Graduate School, University of Incheon)
Min Chang-Keun (Graduate School, University of Incheon)
Publication Information
Korean Journal of Air-Conditioning and Refrigeration Engineering / v.18, no.3, 2006 , pp. 254-261 More about this Journal
Abstract
The effect of enhanced geometry (pore diameter, gap width) is investigated on the pool boiling of R-123/oil mixture for the enhanced tubes having pores with connecting gaps. Tubes with different pore diameters (and corresponding gap widths) are specially made. Significant heat transfer degradation by oil is observed for the present enhanced tubes. At 5% oil concentration, the degradation is 26 to 49% for $T_{sat}=4.4^{\circ}C$. The degradation increases 50 to 67% for $T_{sat}=26.7^{\circ}C$. The heat transfer degradation is significant even with small amount of oil (20 to 38% degradation at 1% oil concentration for $T_{sat}=4.4^{\circ}C$), probably due to the accumulation of oil in sub-tunnels. The pore size (or gap width) has a significant effect on the heat transfer degradation. The maximum degradation is observed for $d_p$ = 0.20 mm tube at $T_{sat}=4.4^{\circ}C$, and for $d_p$=0.23 mm tube at $T_{sat}=26.7^{\circ}C$. The minimum degradation is observed for $d_p$=0.27 mm tube for both saturation temperatures. It appears that the oil removal is facilitated for the larger pore diameter (along with larger gap) tube. The highest heat transfer coefficient with oil is obtained for $d_p$ =0.23 mm tube, which yielded the highest heat transfer coefficient for pure R-123. The heat transfer degradation increases as the heat flux decreases.
Keywords
Enhanced tube; Refrigerant-oil mixture; Pool boiling; R-123; Mineral oil;
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1 Bergles, A. E. and Chyu, M. C., 1982, Characteristics of nucleate pool boiling from porous metallic coatings, J. Heat Transfer, Vol. 104, pp. 279-285   DOI
2 Chen, J. C., 1963, A correlation for boiling heat transfer to saturated fluids in convective flow, 6th National Heat Transfer Conference, ASME Paper 63-HT-34, Boston, MA
3 Webb, R. L. and McQuade, W. F., 1993, Pool boiling of R-11 and R-123 oil-refrigerant mixtures on plain and enhanced tube boiling, ASHRAE Trans., Vol. 99, Pt. 1, pp. 1225-1236
4 Memory, S. B., Sugiyama, D. C. and Marto, P. J., 1995, Nucleate pool boiling of R-1l4 and R-ll4/oil mixtures from smooth and enhanced surfaces - I. single tubes, Int. J. Heat Mass Transfer, Vol. 38, pp. 1347-1361   DOI   ScienceOn
5 Kline, S. J. and McClintock, F. A, 1953, The description of uncertainties in single sample experiments, Mechanical Engineering, Vol. 75, pp.3-9
6 Czikk, A. M., Gottzmann, C. F., Ragi, E. G., Withers, J. G. and Habdas, E. P., 1970, Performance of advanced heat transfer tubes in refrigerant-flooded liquid coolers, ASHRAE Trans., Vol. 76, Pt. 1, pp. 96-109
7 Gottzmann, C. F., O'Neill, P. S.. and Minton, P. E., 1973, High efficiency heat exchangers, Chem. Eng. Prog., Vol. 97, No.7, pp.69-75
8 Wang, C-C., Lin, Y-T., Chung, H-D. and Robert Hu, Y. Z., Some observations of foaming characteristics in the nucleate boiling performance of refrigerant-oil mixture, ASHRAE Trans., Vol. 105, Pt. I, Paper CH99-3-1
9 Chien, L.-H. and Webb, R L., 1998, A nucleate boiling model for structured enhanced surfaces, Int. J. Heat Mass Transfer, Vol. 41, pp. 2183-2195   DOI   ScienceOn
10 Memory, S. B., Bertschi G. and Marta, P. J., 1993, Pool boiling of HCFC-124/oil mixtures from smooth and enhanced tubes, in Heat Transfer with Alternate Refrigerants, HTD-Vol. 243, PP. 9-18
11 Jensen, M. K. and Jackman, D. L., 1984, Prediction of nucleate pool boiling heat transfer coefficients of refrigerant-oil mixtures, J. Heat Transfer, Vol. 106, pp.133-140
12 Zarnescu, V., Webb, R. L. and Chien, L-H., 2000, Effect of oil on the boiling performance of structured and porous surfaces, HVAC&R Research, Vol. 6, No. 1, pp. 41-53   DOI   ScienceOn
13 Wanniarachchi, A. S., Marto, P. J. and Reilly, J. T., 1986, The effect of oil contamination on the nucleate boiling performance of R-114 from a porous coated surface, ASHRAE Trans., Vol. 92, Pt. 2, pp.339-348
14 Kim, N-H. and Choi, K-K., 2001, Nucleate pool boiling on structured enhanced tubes having pores with connecting gaps, Int. J. Heat Mass Transfer, Vol. 44, pp.17-28   DOI   ScienceOn
15 Thome, J. R, 1996, Boiling of new refrigerants: A state-of-the-art review, Int. J. Refrig., Vol. 19, pp.435-457   DOI   ScienceOn