Journal of Energy Engineering (에너지공학)

The Korean Society for Energy (한국에너지학회)
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Airside Performance of Fin-and-Tube Heat Exchangers Having Round Wave Fins

둥근 웨이브 핀-관 열교환기의 공기 측 전열 성능

  • Kim, Nae-Hyun (Division of Mechanical System Engineering, Incheon National University)
  • 김내현 (인천대학교 기계시스템공학부)
  • Received : 2015.03.19
  • Accepted : 2015.08.20
  • Published : 2015.12.31
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Abstract

In this study, airside performance of round fin-and-tube heat exchangers are compared with that of the herringbone wave fin-and-tube heat exchangers with an aim to investigate the effect of fin shape on thermal performance. Results show that j factors of the round wave fin are 1.2~22% larger than those of herringbone wave fin. The f factors of the round wave fin are -1.0~29% smaller than those of herringbone wave fin for 1 or 2 row configuration. For 3 row configuration, f factors of the round wave fin are 8.3~23% larger. The reason may be attributed to the reduced recirculation zone in the valley of the fin for round wave fin as compared with that of the herringbone wave fin. For round wave fin, the effect of fin pitch on j and f factor is not significant. In addition, j factors decrease as the number of tube row increases. On the other hand, f factors are independent of the number of tube row. A new correlation was developed based on the present data.

본 연구에서는 절곡 깊이(1.4 mm)와 절곡 핏치(5.5 mm)가 같은 둥근 웨이브와 각진 웨이브 핀-관 열교환기에 대한 실험을 통하여 절곡 형상이 전열성능에 미치는 영향을 검토하였다. j 인자의 경우 둥근 웨이브 핀이 모든 열수에서 1.2~22% 크고 f 인자는 3열의 경우 8.3~23% 크고 1, 2열의 경우는 -1.0~29% 작다. 둥근 웨이브 핀이 우수한 성능을 보이는 이유로 둥근 웨이브 핀의 경우 각진 웨이브 핀 보다 유동이 핀의 곡면을 잘 따라갈 수 있으므로 골에 존재하는 재순환 영역의 크기가 줄어들기 때문으로 판단된다. 둥근 웨이브 핀의 경우 핀 핏치가 j와 f 인자에 미치는 영향은 크지 않다. 또한 j 인자는 튜브 열수가 증가할수록 감소하는 반면 f 인자는 튜브 열수와 무관하다. 실험 데이터로부터 새로운 상관식을 도출하였다.

Keywords

References

  1. Webb RL, Kim NH, Principles of Enhanced Heat Transfer. Taylor and Francis Pub., 2nd ed., 1994.
  2. Wang CC, On the airside performance of fin-andtube heat exchangers, in Heat Transfer Enhancement of Heat Exchangers. S. Kakac et al. (Eds.), Kluwer Academic Press, 1999, 141-162.
  3. Goldstein L, Sparrow EM, Experiments on the transfer characteristics of a corrugated fin and tube heat exchanger configuration, J. Heat Transfer, 1976, 98, 26-34. https://doi.org/10.1115/1.3450464
  4. Ali MM, Ramadhyani S, Experiments on convective heat transfer in corrugated channels, Experimental Heat Transfer, 1992, 5, 175-193. https://doi.org/10.1080/08916159208946440
  5. Kim NH, Yun JH, Webb RL, Heat transfer and friction correlations for wavy plate fin-and-tube heat exchangers, J. Heat Transfer, 1997, 119, 560-567. https://doi.org/10.1115/1.2824141
  6. Beecher DT, Fagan TJ, Effects of fin pattern on the air-side heat transfer coefficients in plate finned tube heat exchangers, ASHRAE Trans., 1987, 93(2) 1961-1984.
  7. Wang CC, Fu WL, Chang CT, Heat transfer and friction characteristics of typical wavy fin-and-tube heat exchangers, Exp. Thermal Fluid Science, 1997, 14, 174-186. https://doi.org/10.1016/S0894-1777(96)00056-8
  8. Wang CC, Tsai YM, Lu DC, Comprehensive study of convex louver and wavy fin-and-tube heat exchangers, J. Thermophysics Heat Transfer, 1998, 12(3), 423-430. https://doi.org/10.2514/2.6354
  9. Wang CC, Lin YT, Lee CJ, Chang YJ, Investigation of wavy fin-and-tube heat exchangers: A contribution to databank, Experimental Heat Transfer, 1999, 12, 73-89. https://doi.org/10.1080/089161599269825
  10. Wang CC, Chang YJ, Chiou NF, Effects of waffle height on the air-side performance of wavy fin-and-tube heat exchangers, Heat Transfer Engineering, 1999, 20(3), 45-56. https://doi.org/10.1080/014576399271411
  11. Webb RL, Air-side heat transfer correlations for flat and wavy plate fin-and-tube geometries, ASHRAE Trans., 1990, 96(2), 445-449.
  12. Wang CC, Jang JY, Chiou NF, A heat transfer and friction correlation for wavy fin-and-tube heat exchangers, Int. J. Heat Mass Trans., 1999, 42, 1919-1924. https://doi.org/10.1016/S0017-9310(98)00288-9
  13. Mirth DR, Ramadhyani S, Correlations for predicting the air-side Nusselt numbers and friction factors in chilled water cooling coils, Experimental Heat Transfer, 1994, 7, 143-162. https://doi.org/10.1080/08916159408946477
  14. Kang HC, Webb RL, Evaluation of the wavy fin geometry used in air-cooled finned-tube heat exchangers, Proceedings of 11th International Heat Transfer Conference, Aug. 23-28, Kyoungju, Korea, 1998, 6, 95-100.
  15. ASHRAE Standard 41.1, Standard method for temperature measurement, ASHRAE, 1986.
  16. ASHRAE Standard 41.2, Standard method for laboratory air-flow measurement, ASHRAE, 1987.
  17. ASHRAE Standard 41.5, Standard measurement guide, engineering analysis of experimental data, ASHRAE, 1975.
  18. ESDU 98005, Design and performance evaluation of heat exchangers: the effectiveness and NTU method, Engineering and Sciences Data Unit 98005 with Amendment A, London ESDU International plc., 1998, 122-129.
  19. Park BB, You SM, Youn B, Yoo KC, Experimental study of heat transfer and pressure drop characteristics for flow of water inside circular smooth and micro-fin tubes, Korean J. Air Conditioning Refrigeration, 1997, 9(4), 454-461.
  20. Gnielinski V, New equation for heat and mass transfer in turbulent pipe and channel flow, Int. Chem. Eng., 1976, 16, 359-368.
  21. Schmidt TE, Heat transfer calculations for extended surfaces, J of ASRE, Refrigeration Engineering, 1949, 4, 351-357.
  22. Ramadhyani S, Numerical prediction of flow and heat transfer in corrugated ducts, ASME, HTD-Vol. 66, 1986, 37-43.
  23. Torikoshi K, Xi. GN, Nakazawa Y, Asano H, Flow and heat transfer performance of a plate fin and tube heat exchanger (first report: effect of fin pitch), Heat Transfer 1994, Proceedings of the 10th Int. Heat Transfer Conf., 1994, 4, 411-416.
  24. Jang JY, Chen LK, Numerical analysis of heat transfer and fluid flow in a three-dimensional wavy fin-and-tube heat exchanger, Int. J. Heat Mass Transfer, 1997, 40(16), 3981-3990 https://doi.org/10.1016/S0017-9310(97)00047-1
  25. Min CK, Cho JP, Oh WK and Kim NH, Heat transfer and pressure drop characteristics of heat exchangers having plain fins under dry and wet conditions, Korean J. Air-Conditioning and Refrigeration, 2004, 16(3), 218-229.
  26. Wang CC, Lee WS, Sheu WJ, A comparative study of compact enhanced fin-and-tube heat exchangers, Int. J. Heat Mass Transfer, 2001, 44, 3565-3573. https://doi.org/10.1016/S0017-9310(01)00011-4
  27. Rich DG, The effect of fin spacing on the heat transfer and friction performance of multi-row, smooth plate fin-and-tube heat exchangers, ASHRAE Trans., 1973, 72(2) 137-145.