Condensation heat transfer characteristics of moist air outside 3-D finned tubes with different wettability

Energy ◽  
2020 ◽  
Vol 207 ◽  
pp. 118202 ◽  
Author(s):  
Yuheng Gu ◽  
Yudong Ding ◽  
Qiang Liao ◽  
Qian Fu ◽  
Xun Zhu ◽  
...  
2015 ◽  
Vol 23 (02) ◽  
pp. 1550014 ◽  
Author(s):  
Daisuke Jige ◽  
Tomonobu Matsuno ◽  
Norihiro Inoue

The present study experimentally investigated the condensation heat transfer characteristics and condensate flow mode of R245fa on horizontal low-finned and microscopic-grooved tubes. Five low-finned tubes and a microscopic-grooved tube with tube diameters at the fin tip of approximately 19 mm were used. Experiments were conducted at a saturation temperature of 40°C. The fundamental heat transfer characteristics of the low-finned and microscopic-grooved tubes were experimentally investigated to clarify the flow modes of the condensate and the efficacy of the enhanced heat transfer.


Author(s):  
M. Fatouh

The present work aimed at determining the condensation heat transfer characteristics of R134a on single horizontal smooth and finned tubes under different parameters. These are saturated temperature (36°C and 43°C), inlet coolant temperature (25°C and 30°C) and coolant mass flow rate (100: 800 kg/h) for smooth and finned tubes. In the case of finned tubes, the pitch to height ratio varies from 0.5 to 3.08. Experimental condensation heat transfer characteristics for R134a and R12 on a smooth tube are compared. Experimental results confirmed that the heat flux and the overall heat transfer coefficient for R134a increase when coolant mass flow rate, saturation temperature and fin height increase or as both coolant inlet temperature and fin height decrease. The influence of fin pitch, on condensation heat flux and overall heat transfer, is lower than that of fin height. However, the heat flux and the overall heat transfer coefficient for R134a are correlated with the investigated parameters. Finally, the comparison between R12 and R134a revealed that the condensation heat transfer characteristics for R134a are better than those of R12.


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