The Optimum Angle of Attack of Delta Winglet VortexGenerators on Heat Transfer Performance of Finned Flat Tube Bank with Considering Nonuniform Fin Temperature

2006 ◽  
Vol 19 (3) ◽  
pp. 227-249 ◽  
Author(s):  
F. Ke ◽  
L. B. Wang ◽  
L. Hua ◽  
S. D. Gao ◽  
Y. X. Su
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Angle Of Attack ◽  
Transfer Performance ◽  
Tube Bank ◽  
Flat Tube ◽  
Optimum Angle ◽  
Delta Winglet ◽  
Finned Flat Tube Bank

The Optimum Height of Winglet Vortex Generators Mounted on Three-Row Flat Tube Bank Fin

2003 ◽  
Vol 125 (6) ◽  
pp. 1007-1016 ◽  
Author(s):  
S. D. Gao ◽  
L. B. Wang ◽  
Y. H. Zhang ◽  
F. Ke
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Vortex Generators ◽  
Local Characteristic ◽  
Transfer Performance ◽  
Tube Bank ◽  
Flat Tube ◽  
Optimum Height

Winglet vortex generators can be used to enhance the heat transfer performance of finned flat tube bank fin. The effects of the height of vortex generators (VG) on local heat transfer were studied using the naphthalene sublimation method and the optimum height of winglet VG are screened by using JF, a dimensionless factor of the larger the better characteristics. In order to get JF, the local heat transfer coefficient obtained in experiments and a numerical method were used to get the heat transferred from the fin. For the configurations studied in this paper: for local characteristic, as increasing height of VG, heat transfer is enhanced, but the mostly enhanced region moves away from the tube wall; with increasing height of VG to certain degree, the width of enhanced region does not increase significantly; the effects of VG’s height on span-average Nusselt number (Nu) are more mixed on fin surface mounted with VGs and its back surface, with increasing height of VG, in some region heat transfer is worsened, and in other region heat transfer is enhanced; in real working condition, the heat transferred from fin surface mounted with VGs is larger than the heat transferred from the other surface of the fin; increasing the height of VG (H) increases average Nu and friction factor (f ), but with considering the fin efficiency, there is an optimum H to get best heat transfer performance; the optimum height of VG is dependent on the thickness of fin and its heat conductivity, for mostly used fin thickness and material, the optimum height of VG is 0.8 times of net fin spacing.

Investigation of heat transfer performance and flow characteristic in helically coiled-twisted flat tube

2019 ◽  
Vol 33 (5) ◽  
pp. 419-439 ◽  
Author(s):  
Xu Peng ◽  
Dingbiao Wang ◽  
Guanghui Wang ◽  
Yushen Yang ◽  
Sa Xiang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Flow Characteristic ◽  
Transfer Performance ◽  
Flat Tube

Experimental Study on Heat Transfer Performances of Flat Tube Bank Fin Heat Exchanger Using Four Different Fin Patterns

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Feng-Cai Zheng ◽  
Song Liu ◽  
Zhi-Min Lin ◽  
Jaafar Nugud ◽  
Liang-Chen Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Exchangers ◽  
Transfer Enhancement ◽  
Tube Bank ◽  
Number Range ◽  
Flat Tube ◽  
Louvered Fin ◽  
Delta Winglet ◽  
Better Than

Air-side heat transfer and flow friction characteristics of four different fin patterns suitable for flat tube bank fin heat exchangers are investigated experimentally. The fin patterns are the fin with six dimples, the fin with nine dimples, the double louvered fin, and the fin with delta-winglet vortex generators (VGs). The corresponding plain fins (plain fin I and plain fin II) are used as the references for evaluating the thermal performances of these fin patterns under identical pump power constraint. The performance of the fin with the six dimples is better than that with nine dimples. The performance of the fin with delta-winglet VGs is better than that of the double louvered fin, and the performance of the latter is better than that of the fins with six or nine dimples. In the tested Reynolds number range, the heat transfer enhancement performance factor of the fin with six dimples, the fin with nine dimples, the double louvered fin, and the fin with delta-winglet VGs is 1.2–1.3, 1.1–1.2, 1.3–1.6, and 1.4–1.6, respectively. The correlations of Nusselt number and friction factor with Reynolds number for the fins with six/nine dimples and the double louvered fin are obtained. These correlations are useful to design flat tube bank fin heat exchangers.

Simulation Investigation on Multi-Unit Parallel-Flow Type Condenser with Flat Tubes Distribution

2013 ◽  
Vol 423-426 ◽  
pp. 1910-1913
Author(s):  
Jian Rong Du ◽  
Zu Yi Zheng ◽  
Jun Hua Wan ◽  
Yi De Wang ◽  
Zhong Min Wan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Air Velocity ◽  
Flat Tube ◽  
Tube Arrangement ◽  
First Pass ◽  
Flat Tubes

Three heat exchangers, all of which have 38 tubes in total and 6 passes, with different tube arrangements were simulation investigated in laboratory. The effect of flat tube distribution on heat transfer performance and pressure drop characteristic was simulation investigated. The effect of different air velocity and flow on heat transfer performance and pressure drop characteristic was simulation investigated too. The results show that similar tube distribution has little effect on heat transfer but has great effect on pressure drop. It was found the tube arrangement from first pass to sixth pass is 10,9,6,5,4,4 has the best heat transfer performance and its pressure drop is small. The heat transfer and pressure drop increase with the air velocity and refrigerant flow.

Experimental Investigation on Multi-Unit Parallel-Flow Type Condenser with Flat Tubes Distribution

2014 ◽  
Vol 701-702 ◽  
pp. 1233-1236
Author(s):  
Lv Xian Zeng ◽  
Zu Yi Zheng ◽  
Jun Hua Wan ◽  
Xi Chen ◽  
Zhong Min Wan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Air Velocity ◽  
Flat Tube ◽  
The Third ◽  
Flat Tubes ◽  
Simulation Results

Three heat exchangers, all of which have 38 tubes in total and 6 passes, with different tube arrangements were manufactured to be experimental investigated in laboratory. The effect of flat tube distribution on heat transfer performance and pressure drop characteristic was experimental investigated. The effect of different air velocity and flow on heat transfer performance and pressure drop characteristic was also experimental investigated. The results show that similar tube distribution has little effect on heat transfer quality but has great effect on pressure drop. It was found the third arrangement has the best heat transfer and its pressure drop is small. Thus the third arrangement is the best solution. The heat transfer and pressure drop increase with the air velocity and refrigerant flow, so a proper value should be chosen, it was found that the simulation results were mainly agreement with the experimental results.

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