세관 내 응축 열전달 특성에 관한 연구
Study on the Condensation Heat Transfer Characteristics in Small Diameter Tubes
2
조회
0
다운로드
0
인용
0
참고문헌
키워드
초록
Abstract
The Condensation heat transfer coefficients of R-22 and R-134a were measured in smooth horizontal copper tubes with inner diameters of 1.77, 3.36 and 5.35 mm, respectively. The experiments were conducted in a closed loop, which was driven by a magnetic gear pump. They were performed for the following ranges of variables: mass flux (200 to 500 kg/m2·s), saturation temperature 30 ℃ and quality (0 to 1.0).The main results obtained are as follows : Condensation heat transfer coefficients in the small diameter tubes (ID ＜ 7 mm) were observed to be strongly affected by inner diameter change and to differ from those in the large diameter tubes. The heat transfer coefficients in the small diameter tubes were 20 ∼ 40 % higher than those in the large diameter tubes as the inner diameter of the tube was reduced. Also, it was very difficult to apply some well-known previous predictions (Cavallini-Zecchin's, Haraguchi's and Dobson's correlation) to small diameter tubes. Based on an analogy between heat and mass transfer, the new correlation is proposed to predict the experimental data more accurately.
참고문헌 (19)
- "Experimental evaluation of internal condensation of refrigerations R-12 and R-134a", pp.744~754 (1994)
- "A general correlation for heat transfer during film condensation inside pipes", int. j. heat and mass transfer(22), pp.547~556 (1979)
- "Forced convective condensation in tubes A heat transfer correlation for condenser design", pp.157~165 (1973), Rehsenow
- "A dimensionless correlation for heat transfer in forced convective condensation Proceedings of the Fith International Heat Transfer Conference 3", pp.309~313 (1974)
- "멀티 패스 R-134a의 응축열전달율 및 압력손실", 14(5), pp.273~283 (1995)
- "A predictive model for condensation in small hydraulic diameter tubes having axial micro-fins", 119, pp.776~ (1997)
- "Condensation heat transfer in small diamet-er tubes", 6, pp.403~408 (1998)
- "NIST Thermodynamic Properties and Refrigerant Mixtures Database", pp.~50 (1996), National Institute of Standards and Technology
- "R-22 및 R-134a의 세관 내 유동 특성에 관한 연구", 14(9), pp.756~765 (2002)
- "三成分混合冷媒の沸騰,凝縮熱傳達における管經の影響" (1996)
- "Condensing Heat Transfer within Horizontal Tubes", pp.55 171~29 182 (1959)
- "A general heat transfer correlation for annular flow condensation", pp.90267~276 (1968)
- "Condensation of refrigerant HCFC- 22 HFC-134a and HCFC-123 in a horizontal smooth tube Tran of the JSME", pp.2117~2116 (1994)
- "Condensation heat transfer and pressure drop of refrigerant R-134a in a small pipe", 42, pp.697~708 (1999)
- "University of California Publications on Engineering", 2, pp.443~ (1930)
- "Burnout in steam-water flows with axially nonuniform heat flux" (1968)
- "Dynamics of vapor bubbles and boiling heat transfer", pp.531~535 (1955)
- "A critical review of correlations for convective vaporization in tubes and tube banks J. of Heat Transfer Eng.", 13(s. 3), pp.58~81 (1992)
- "공학도를 위한 수치해 석", 희중당, pp.476~510 (1994)