• Title/Summary/Keyword: fined-tube

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A Study on the Manufacturing Process for High-finned Tube of Copper Pipe using Roll Forming Method (전조공법을 이용한 동관의 하이핀 튜브 제조 공정에 대한 연구)

  • Kim, Tae-Gyu
    • Korean Journal of Materials Research
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    • v.16 no.2
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    • pp.111-115
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    • 2006
  • High-finned tubes have good thermal conductivity and have better cooling efficiency than plain tubes or low-fined tubes due to bigger air contact area. During high-fined tubes are manufactured by roll forming, the main technique is illustrated to optimizing primary material(copper pipe), optimized die matrix designing technique for roll forming, control manufacturing speed to develop productivity etc. In this study, a roll forming system was developed in oder to produce high-finned tube. Also a multi-step roll forming die was designed & built to produce high-finned tube that has over 10 mm fin height. And then, roll forming test using copper pipe was performed to produce high-finned tube. Roll forming process for producing highfinned tube was optimized by analyzing and adjusting misrostructure, hardness, and surface roughness of roll formed high-fined tube.

Air-side Heat Transfer and Friction Characteristics of Fined-tube Heat Exchangers under Heating Condition (핀-관 열교환기의 난방운전 시 공기측 열전달 및 마찰특성)

  • Kwon, Young Chul;Chang, Keun Sun;Ko, Kuk Won;Kim, Young Jae;Park, Byung Kwon
    • Applied Chemistry for Engineering
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    • v.17 no.5
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    • pp.476-482
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    • 2006
  • An experimental study has been performed to investigate the characteristics of air-side heat transfer and friction of a fined tube heat exchanger under heating conditions. Air enthalpy calorimeter was used to obtain the performance evaluation and analysis of the fined tube heat exchanger. Eight finned tube heat exchangers with slit fin, louver fin, and plain fin were used. The air-side heat transfer coefficient was calculated by the log-mean-temperature-difference. Air-side heat transfer and friction were presented in terms of j factor and friction factor on Reynolds number. From the experimental result, it was found that the variations of air-side heat transfer and friction of fined tube heat exchanger with the change of the fin configuration, row number, fin pitch, and tube circuit were obtained. j factor and friction factor decreased with Reynolds number increased. The tube circuit affected the air-side heat transfer and friction. In the case of slit and louver fin, j factor of 1st row was higher than that of 2nd row. But, with increasing Re, j factor was reversed. The characteristics of j factor and friction factor of 2nd row heat exchanger were different according to the kind of fins.

Performance and Heat transfer Characteristics of Louver Fin-tube Heat Exchanger for Simultaneous Cooling/Heating Heat Pump (동시 냉난방 히트펌프용 루버핀-관 열교환기 성능 및 전열특성 실험연구)

  • Kwon, Young-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.8 no.6
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    • pp.1337-1342
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    • 2007
  • An experimental study has been performed to investigate the performance and heat transfer characteristics of the heat exchanger for simultaneous cooling/heating heat pump. The heat transfer performance was measured using an air-enthalpy calorimeter and a constant temperature water bath, to obtain the performance evaluation and analysis of a fined tube heat exchanger. Six finned tube heat exchangers with louver fin were tested under a heating condition. Air-side heat transfer and friction were presented in terms of j-factor and f-factor. The heat transfer coefficient increased with decreasing the fin pitch, j-factor and f-factor on the fin pitch and the number of tube rows decreased with increasing Reair.

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Air-side Heat Transfer and Friction Characteristics of Finned Tube Beat Exchangers with Slit Fin or Plain Fin (슬릿과 평판 핀-관 열교환기의 공기측 열전달 및 마찰특성)

  • Kwon, Young-Chul;Chang, Keun-Sun;Park, Byung-Kwon;Kwon, Jeong-Tae;Jeong, Ji-Hwan
    • Journal of Energy Engineering
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    • v.16 no.1 s.49
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    • pp.7-14
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    • 2007
  • An experimental study is performed to investigate the effect of air-side heat transfer and friction on characteristics of finned tube heat exchanger under dry surface and wet surface conditions (RH 50%, 70%). Air enthalpy calorimeter is used to obtain the performance evaluation and analysis of a fined tube heat exchanger. Four finned tube heat exchangers with slit fin or plain fin are tested. The number of tube rows are 2 and 3, and the tube diameter is 7 mm. Air-side heat transfer and friction are presented in terms of j factor and friction factor. At dry surface condition, j factor decreases with increasing Re and j factor of 3 row is lower than that of 2 row. Also, the friction factor of a slit fin is larger than that of a plain fin. At wet surface condition, the heat transfer effect is more significant in the case of the slit fin than the plain fin and 2 row than 3 row. The j factor and friction factor are affected by humidity, tube row and fin configuration.