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

The Korean Society of Mechanical Engineers (대한기계학회)
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Evaporation Heat Transfer and Pressure Drop of R-410A in a 7.0 mm O.D. Microfin Tube at Low Flow Rates

낮은 유량에서 외경 7.0 mm 마이크로핀 튜브 내 R-410A 증발 열전달 및 압력 손실

  • Kim, Nae-Hyun (Div. of Mechanical System Engineering, Incheon Nat'l Univ.)
  • 김내현 (인천대학교 기계시스템공학부)
  • Received : 2015.05.22
  • Accepted : 2015.07.08
  • Published : 2015.09.01
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Abstract

Microfin tubes having an outside diameter (O.D.) of 7.0 mm are widely used in residential air conditioning systems and heat pumps. It is known that the mass fluxes for air conditioners and heat pumps under partial load conditions are several tens of $kg/m^2s$. However, literature surveys reveal that previous investigations were limited to mass flux over $100kg/m^2s$. In this study, we conduct R-410A evaporation heat-transfer tests at low mass fluxes ($50-250kg/m^2s$) using a 7.0 mm O.D. microfin tube. During the test, the saturation temperature was maintained at $8^{\circ}C$, and the heat flux was maintained at $4.0kW/m^2$. For comparison purposes, we also test a smooth tube with a 7.0 mm O.D. The results showed that the heat-transfer enhancement factor of the microfin tube increased as the mass flux decreased up to $150kg/m^2s$, which decreased as the mass flux further decreased. The reason for this was attributed to the change of the flow pattern from an annular flow to a stratified flow. Within the test range, the frictional pressure drops of the microfin tube were approximately the same as those of the smooth tube. We then compare experimental data obtained with the predictions obtained for the existing correlations.

가정용 에어컨이나 히트 펌프에 외경 7.0 mm 마이크로핀 튜브가 널리 사용되고 있다. 한편 에어컨이나 히트펌프의 부분 부하 운전시 질량유속은 수십 $kg/m^2s$에 불과하다. 하지만 7.0 mm 튜브에 대한 기존 연구들은 질량유속 $100kg/m^2s$ 이상에서 수행되었다. 본 연구에서는 낮은 질량유속 ($50kg/m^2s$에서 $250kg/m^2s$)에서 외경 7.0 mm 마이크로핀 튜브 내 R-410A 증발 열전달 실험을 수행하였다. 실험 중 포화온도는 $8^{\circ}C$, 열유속 $4.0kW/m^2$으로 유지하였다. 비교를 위해 외경 7.0mm 평활관에 대한 실험도 수행하였다. 실험결과 마이크로핀 튜브의 전열촉진비는 질량유속이 감소할수록 증가하다 $150kg/m^2s$를 기점으로 감소함을 보였다. 이는 마이크로 핀튜브 내 유동이 환상류에서 성층류로 변화하기 때문이다. 실험 범위에서 마이크로핀 튜브의 마찰손실과 평활관의 마찰손실은 거의 같게 나타났다. 실험데이터를 기존 상관식의 예측치와 비교하였다.

Keywords

References

  1. Webb, R. L. and Kim, N. H., 2005, Principles of Enhanced Heat Transfer, 2nd ed., Taylor and Francis Pub.
  2. Laohalertdecha, S., Dalkilic, A. S. and Wongwises, S., 2012, "A Review on Heat Transfer Performance and Pressure Drop Characteristics of Various Enhanced Tubes," Int. J. Air-Cond. Refrig., Vol. 20, No. 4, 230003.
  3. Thome, J. R., 1996, "Boiling of New Refrigerants: A State-of-the-Art Review," Int. J. Refrig., Vol. 19, No. 7, pp. 435-457. https://doi.org/10.1016/S0140-7007(96)00004-7
  4. Fujie, K. Itoh, N., Kimura, H., Nakayama, N. and Yanugidi, T., 1977, Heat Transfer Pipe, US Patent 4044479, Assigned to Hitachi Ltd.
  5. Shinohara, Y. and Tobe, M., 1985, "Development of an Improved Thermofin Tube," Hitachi Cable Review, Vol. 4, pp. 47-50.
  6. Yasuda, K., Ohizumi, K., Hori, M. and Kawamata, O., 1990, "Development of Condensing Thermofin HEXC tube," Hitachi Cable Review, Vol. 9, pp. 27-30.
  7. Tsuchida, T., Yasuda, K., Hori, M. and Otani, T., 1993, "Internal Heat Transfer Characteristics and Workability of Narrow Thermofin Tubes," Hitachi Cable Review, Vol. 12, pp. 97-100.
  8. Webb, R. L., 1999, "Prediction of Condensation and Evaporation in Microfin and Micro-channel Tubes," Heat Transfer Enhancement of Heat Exchangers: Kluwer Academic Press, pp. 529-550.
  9. Thome, J. R., 2004, Engineering Data Book III, Wolverine Tube Inc.
  10. Hamilton, L. J., Kedzierski, M. A. and Kaul, M. P., 2008, "Horizontal Convective Boiling of Pure and Mixed Refrigerants Within a Micro-fin Tube," J. Enhanced Heat Transfer, Vol. 15, No. 3, pp. 211-226. https://doi.org/10.1615/JEnhHeatTransf.v15.i3.30
  11. Bogart, J. and Thors, P., 1999, "In-tube Evaporation and Condensation of R-22 and R-410A with Plain and Internally Enhanced Tubes," J. Enhanced Heat Transfer, Vol. 6, No. 1, pp. 37-50. https://doi.org/10.1615/JEnhHeatTransf.v6.i1.40
  12. Inoue, N, Goto, M. and Kandlikar, S. G., 2000, "Flow Boiling Heat Transfer with Binary and Ternary Mixtures in Microfin Tubes," Advances in Enhanced Heat Transfer, ASME, HTD-Vol. 365/PID-Vol. 4, pp. 23-33.
  13. Kim, Y., Seo, K. and Chung, J. T., 2002, "Evaporation Heat Transfer Characteristics of R-410A in 7.0 and 9.52 mm Smooth/Microfin Tubes," Int. J. Refrig., Vol. 25, pp. 716-730. https://doi.org/10.1016/S0140-7007(01)00070-6
  14. Houfuku, M., Suzuki, Y. and Inui, K., 2001, "High Performance, Light Weight Thermofin Tubes for Air-Conditioners Using Alternative Refrigerants," Hitachi Cable Review, Vol. 20, pp. 97-100.
  15. Kim, M. H. and Shin, J. S., 2005, "Evaporation Heat Transfer of R-22 and R-410A in Horizontal Smooth and Microfin Tubes," Int. J. Refrig., Vol. 28, pp. 940-948. https://doi.org/10.1016/j.ijrefrig.2005.01.016
  16. Wu, Z., Wu, Y., Sunden, B. and Li, W., 2013, "Convective Vaporization in Micro-fin Tubes of Different Geometries," Exp. Thermal Fluid Sci., Vol. 44, pp. 398-408. https://doi.org/10.1016/j.expthermflusci.2012.07.012
  17. Steiner, D. and Taborek, J., "Flow Boiling Heat Transfer in Vertical Tubes Correlated by an Asymtotic Model, " Heat Transfer Eng., Vol. 13, No. 3., pp, 43-69.
  18. Padovan, A., Del Col, D. and Rossetto, L., 2001, "Experimental Study on Flow Boiling of R134a and R410A in a Horizontal Microfin Tube at High Saturation Temperatures," Applied Thermal Engineering, Vol. 31, pp. 2814-3826.
  19. Cavallini, A., Del Col, D. and Rossetto, L., 2006, "Flow Boiling Inside Microfin Tubes: Prediction of the Heat Transfer Coefficient," Proc. ECI International Conference on Boiling Heat Transfer, Spoleto, Italy.
  20. Hu, H., Ding, G. and Wang, K., 2008, "Heat Transfer Characteristics of R410A-oil Mixture Flow Boiling Inside a 7mm Straight Microfin Tube, Int. J. Refrig., Vol. 31, pp. 108-1093.
  21. Ding, G., Hu, H., Huang, X., Deng, B. and Gao, Y., 2009, "Experimental Investigation and Correlation of Two-phase Friction Pressure Drop of R410A-oil Mixture Flow Boiling in a 5 mm Microfin Tube," Int. J. Refrig., Vol. 32, pp. 150-161. https://doi.org/10.1016/j.ijrefrig.2008.08.009
  22. Kim, N. H., Byun, H. W. and Lee, J. W., 2013, "Condensation Heat Transfer and Pressure Drop of R-410A in Three 7.0 mm Outer Diameter Microfin Tubes Having Different Inside Geometries," J. Enhanced Heat Transfer, Vol. 20, No. 3, 235-250. https://doi.org/10.1615/JEnhHeatTransf.2013007609
  23. Wilson, E. E., 1915, "A Basis for Rational Design of Heat Transfer Apparatus," Trans. ASME, Vol. 37, pp. 47-70.
  24. Kline, S. J. and McClintock, F. A., 1953, "The Description of Uncertainties in Single Sample Experiments," Mechanical Engineering, Vol. 75, pp. 3-9
  25. Shah, M. M., 1982, "Chart Correlation for Saturated Boiling Heat Transfer: Equations and Further Study," ASHRAE Trans, Vol. 88, Pt. 1, pp. 185-196.
  26. Kandlikar, S. G., 1990, "A General Correlation for Two-phase Boiling Heat Transfer Coefficient Inside Horizontal and Vertical Tubes," J. Heat Transfer, Vol. 112, pp. 219-228. https://doi.org/10.1115/1.2910348
  27. Gungor, K. E. and Winterton, R. H. S., 1987, "Simplifide General Correlations for Saturated Flow Boiling and Comparisons of Correlations with Data," Can. J. Chem. Eng., Vol. 65, No. 1, pp. 148-156. https://doi.org/10.1002/cjce.5450650124
  28. Wojtan, L., Ursenbacher, T. and Thome, J. R., 2005, "Investigation of Flow Boiling in Horizontal Tubes: Part II-Development of New Heat Transfer Model for Stratified-wavy, Dryout and Mist Flow Regimes," Int. J. Heat Mass Transfer, Vol. 48, pp. 2970-2985. https://doi.org/10.1016/j.ijheatmasstransfer.2004.12.013
  29. Doretti, L., Zilio, C., Mancin, S. and Cavallini, A., 2013. "Condensation Flow Patterns Inside Plain and Microfin Tubes: A Review," Int. J. Refrig., Vol. 36, pp. 567-587. https://doi.org/10.1016/j.ijrefrig.2012.10.021
  30. Koyama, S. Yu, J., Momoki, S., Fujii, T. and Honda, H., 1995, "Forced Convective Flow Boiling Heat Transfer of Pure Refrigerants Inside a Horizontal Microfin Tube," Proc. of Engineering Foundation Conference on Convective Flow Boiling, ASME, Banff, Canada.
  31. Kido, O., Taniguchi, M., Taira, T. and Uehara, H., 1995, "Evaporation Heat Transfer of HCFC22 Inside an Internally Grooved Horizontal Tube," Proc. of ASME/JSME Thermal Engineering Conference, Vol. 2, pp. 323-330.
  32. Thome, J. R., Kattan, N. and Favrat, D., 1977, "Evaporation in Micro-fin Tubes: A Generalized Prediction Model," Proc. of Convective Flow and Pool Boiling Conf., Kloster Irsee, Paper VII-4.
  33. Goto, M., Inoue, N. and Ishiwatari, N., 2001, "Condensation and Evaporation Heat Transfer of R-410A Inside Internally Grooved Horizontal Tubes," Int. J. Refrig., Vol. 24, pp. 628-638. https://doi.org/10.1016/S0140-7007(00)00087-6
  34. Newell, T. A. and Shah, R. K., 2001, An Assessment of Refrigerant Heat Transfer, Pressure Drop and Void Fraction Effects in Microfin Tubes, Int. J. HVAC&R, Vol. 7, No. 2, pp. 125-153. https://doi.org/10.1080/10789669.2001.10391267
  35. Yun, R., Kim, Y., Seo, K. and Kim, H. Y., 2002, "A Generalized Correlation for Evaporation Heat Transfer of Refrigerants in Micro-fin Tubes," Int. J. Heat Mass Transfer, Vol. 45, pp. 2003-2010. https://doi.org/10.1016/S0017-9310(01)00321-0
  36. Chamra, L. M. and Mago, P. J., 2007, "Modeling of Evaporation Heat Transfer of Pure Refrigerants and Refrigerant Mixtures in Microfin Tubes," Proc. of Institution on Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, Vol. 221, pp. 443-454.
  37. Collier, J. G. and Thome, J. R., 1994, Convective Boiling and Condensation, 3rd ed., Oxford University Press.
  38. Zivi, S. M., 1964, "Estimation of Steady-state Steam Void Fraction by Means of the Principle of Minimum Entropy Production," J. Heat Transfer, Vol. 68, pp. 247-252.
  39. Smith, S. L., 1969-1970, "Void Fraction in Two-Phase Flow: A Correlation Based upon an Equal Velocity Head Model," Inst. Mech. Eng., Vol. 184, pp. 647-657.
  40. Rouhani, Z. and Axelsson, E., 1970, "Calculation of Void Volume Fraction in the Subcooled and Quality Boiling Regions," Int. J. Heat Mass Trans., Vol. 13, pp. 383-393. https://doi.org/10.1016/0017-9310(70)90114-6
  41. Friedel, L., 1979, "Improved Pressure Drop Correlations for Horizontal and Vertical Two-phase Pipe Flow," 3R Int., Vol. 18, pp. 485-492.
  42. Muller-Steinhagen, H. and Heck, K., 1986, "A Simple Friction Pressure Drop Correlation for Twophase Flow in Pipes," Chem. Eng. Processing, Vol. 20, pp. 297-308. https://doi.org/10.1016/0255-2701(86)80008-3
  43. Jung, D. and Radermacher, R., 1989, "Prediction of Pressure Drop During Horizontal Annular Flow Boiling of Pure and Mixed Refrigerants," Int. J. Heat Mass Transfer, Vol. 32, No. 12, pp. 2435-2446. https://doi.org/10.1016/0017-9310(89)90203-2
  44. Moreno Quiben, J. and Thome, J. R., 2007, "Flow Pattern Based Two-phase Frictional Pressure Drop Model for Horizontal Tubes, Part II: New Phenomenological Model," Int. J. Heat Fluid Flow, Vol. 28, pp. 1060-1072. https://doi.org/10.1016/j.ijheatfluidflow.2007.01.004
  45. Kuo, C. S. and Wang, C. C., 1996, "Horizontal Flow Boiling of R22 and R407C in a 9.52 mm Micro-fin Tube," Applied Thermal Eng., Vol. 16, No. 8, pp. 719-731. https://doi.org/10.1016/1359-4311(95)00076-3
  46. Cavallini, A. Del Col, D., Doretti, L., Longo, G. A. and Rossetto, L., 1997, "Pressure Drop During Condensation and Vaporization of Refrigerants Inside Enhanced Tubes," Heat and Technology, Vol. 15, No. 1, pp. 3-10.
  47. Choi, J. Y., Kedzierski, M. A. and Domanski, P. A., 2001, "Generalized Pressure Drop Correlation for Evaporation and Condensation in Smooth and Microfin Tubes," Proc. of IIF-IIR Commission B1,Paderborn, Germany, B4, pp. 9-16.
  48. Bandarra Filho, E. P., Saiz Jabardo, J. M. and Lopez Barbieri, P. E., 2004, "Convective Boiling Pressure Drop of Refrigerant R-134a in Horizontal Smooth and Microfin Tubes," Int. J. Refrig, Vol. 27, pp. 895-903. https://doi.org/10.1016/j.ijrefrig.2004.04.014