Evaporation heat transfer enhancement by a laser-textured heterogeneous surface

2021 ◽  
pp. 127359
Author(s):  
Chin-Chi Hsu ◽  
Hui-Chung Cheng ◽  
Tien-Li Chang ◽  
Ping-Hei Chen
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Heterogeneous Surface ◽  
Transfer Enhancement ◽  
Evaporation Heat ◽  
Evaporation Heat Transfer

Condensation and Evaporation Heat Transfer Characteristics of Low Mass Fluxes in Horizontal Smooth Tube and Three-Dimensional Enhanced Tubes

2019 ◽  
Vol 12 (2) ◽  
Author(s):  
Xiang Ma ◽  
Wei Li ◽  
Chuan-cai Zhang ◽  
Zhi-chuan Sun ◽  
David J. Kukulka ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mass Flux ◽  
Three Dimensional ◽  
Saturation Temperature ◽  
Transfer Enhancement ◽  
Heat Transfer Characteristics ◽  
Evaporation Heat ◽  
Enhanced Tubes ◽  
Evaporation Heat Transfer ◽  
Enhanced Surface

Abstract An experimental investigation of condensation and evaporation heat transfer characteristics was performed in 15.88-mm-OD and 12.7-mm-OD smooth and three-dimensional enhanced tubes (1EHT, 3EHT) using R134A and R410A as the working fluid. The enhanced surface of the 1EHT tube is made up of dimples and a series of petal arrays; while the 3EHT tube is made up of rectangular cavities. Evaluations are performed at a saturation temperature of 45 °C, over the quality range of 0.8–0.2 for condensation; while for evaporation the saturation temperature was 6 °C and the quality ranged from 0.2 to 0.8. For condensation, the enhancement ratio (enhanced tube/smooth tube) of the heat transfer coefficients was 1.42–1.95 for the mass flux ranging from 80 to 200 kg/m2s; while for evaporation, the heat transfer enhancement ratio is 1.05–1.42 for values of mass flux that range from 50 to 180 kg/m2s. Furthermore, the 1EHT tube provides the best condensation and evaporation heat transfer performance, for both working fluids at the mass flux considered. This performance is due to the dimples in the enhanced surface that produce interface turbulence; additionally, the increased surface roughness causes additional disturbances and secondary flows near the boundary, producing higher heat fluxes. The main objective of this study was to evaluate the heat transfer enhancement of two enhanced tubes when using R134A and R410A as a function of mass flux, saturation temperature, and tube diameter. As a result of this study, it was determined that the heat transfer coefficient decreases with an increase in saturation temperature and tube diameter.

Evaporation Heat Transfer and Pressure Drop of R-410A in a 5.0 mm O.D. Smooth and Microfin Tube

2015 ◽  
Vol 23 (01) ◽  
pp. 1550004 ◽  
Author(s):  
Nae-Hyun Kim
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Mass Flux ◽  
Saturation Temperature ◽  
Helix Angle ◽  
Apex Angle ◽  
Transfer Enhancement ◽  
Penalty Factor ◽  
Evaporation Heat ◽  
Evaporation Heat Transfer

R-410A's evaporation heat transfer and pressure drop data are provided for a 5.1 mm O.D. microfin tube having 40 fins with 18° helix angle and 40° fin apex angle. Tests were conducted for a range of quality (0.2–0.6), mass flux (260–433 kg/m2s), heat flux (10–20 kW/m2) and saturation temperature (8–12°C). Data are compared with smooth tube counterpart. It was found that both heat transfer coefficient and pressure drop increased as mass flux increased. The range of pressure drop penalty factor (1.10–1.70) was slightly smaller than that of heat transfer enhancement factor (1.39–1.79). Data are compared with available heat transfer and pressure drop correlations.

Heat Transfer Enhancement in Spirally Corrugated Tube

2014 ◽  
Vol 7 (6) ◽  
pp. 970 ◽  
Author(s):  
Tholudin Mat Lazim ◽  
Zaid Sattar Kareem ◽  
M. N. Mohd Jaafar ◽  
Shahrir Abdullah ◽  
Ammar F. Abdulwahid
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Transfer Enhancement ◽  
Corrugated Tube
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