Korean Journal of Air-Conditioning and Refrigeration Engineering (설비공학논문집)

The Society of Air-Conditioning and Refrigerating Engineers of Korea (대한설비공학회)
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Study on the Heat Transfer Characteristics of Immerged and Falling Flows on Helical Tubes

헬리컬관외 침전 및 적하 열전달 특성에 관한 연구

  • 황승기 (한국해양대학교 냉동공조공학과 대학원) ;
  • 윤상국 (한국해양대학교 기계정보공학부) ;
  • 김동혁 (한국해양대학교 기계정보공학부) ;
  • 이승갑 (삼성전자 냉동공조사업부)
  • Published : 2001.04.01
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Abstract

An experimental study is carried out to investigate the characteristics of heat transfer of outside helical tubes. The main heat exchanger consists of twelve curved columns with each 300mm diameter and the total length of 1.2m copper tube having an outer diameter of 19.05mm with 1.5mm thickness. Water flows down the outside of helical tube, where flow patterns are the vertical film falling flow, immerged flow, and mixed-flow which is the combination of film falling flow and immerged flow. Refrigerant 11 flow the inside of the tube countercurrently. The experimental range of inside flow rate is 1.7~3.2$\ell$/min and outside flow rate is 21-33$\ell$/min. The results are presented as Nusselt number with corresponding Reynolds number for variety of outside and inside flow rates. The heat transfer rates of the mixed flow are 8 to 56% higher than those of film falling flow or immerged flow only. Interpretation of the results is given on the basis of physical reasoning and the correlation equations.

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References

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