Heat Transfer Performance through a Flat Tube Using Rotary Helical Screw-tape Inserts

2015 ◽  
Vol 29 (5) ◽  
pp. 691-706 ◽  
Author(s):  
M. A. Omara
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Transfer Performance ◽  
Flat Tube

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

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.

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.

scholarly journals Structural parameters study on stainless-steel flat-tube heat exchangers with corrugated fins

2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2743-2756
Author(s):  
Guifeng Gao ◽  
Fei Wang ◽  
Yongzhang Cui
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Flue Gas ◽  
Heat Transfer Performance ◽  
Structural Parameters ◽  
Transfer Performance ◽  
Gas Temperature ◽  
Flat Tube ◽  
Gas Condensation ◽  
Fin Length

A stainless steel corrugated fins and flat-tube heat exchanger is designed, which has a plate-fin structure. To optimize the structural parameters of this exchanger, including corrugation angle, corrugation pitch and fin length, 3-D simulation model and test were proposed. The numerical results indicated that the corrugation angle significantly affects both on heat transfer performance and pressure drop. The fin with angle, A = 0~20?, have demonstrated the higher heat transfer efficiency, lesser gas condensation, lower pressure drop, higher outlet flue gas temperature in low T region, and no exceeding the distortion temperature in high T region. Corrugation pitch and fin length influence thermal and hydraulic characteristics, outlet flue gas temperature, and fin temperature. To improve heat transfer performance, and reduce the fin temperature in high T region and ease gas condensation in low T region, smaller corrugation pitch and shorter fin length were recommended in the low T region, whereas higher values were more reasonable in high T region. Noticeably, the heat transfer and flow characteristics were better in the high T region than the low T region. Therefore, higher priority should be given to the structural optimization in the high T region in order to in-crease the heat transfer enhancement

Heat Transfer Performance of Finless Flat Tube Heat Exchanger With Vortex Generator

2010 ◽  
Author(s):  
Hajime Onishi ◽  
Haruka Yonekura ◽  
Yukio Tada ◽  
Akira Takimoto
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Vortex Shedding ◽  
Heat Transfer Performance ◽  
Vortex Generator ◽  
Longitudinal Vortex ◽  
Transfer Performance ◽  
Flat Tube ◽  
Longitudinal Vortices ◽  
Tube Heat Exchanger

As the longitudinal vortex is known to be effective in enhancing heat transfer, a three-dimensional unsteady numerical analysis has been made especially for the flow and thermal fields in a unit element of flat tube heat exchanger with vortex generator (VG) in so-called middle Reynolds number range. Both staggered and in-lined arrangements of the tubes with VG are considered and results obtained from the case with VG are compared with those without VG. The study was aimed at the influence of Reynolds number and some geometrical parameters on the heat transfer and the pressure drop. Moreover, as little research has been considered the interaction between transverse vortices and longitudinal vortices in the literatures, the effect is also investigated. It is found that the longitudinal vortex plays an important role in enhancing the local heat transfer by exchanging the fluid from the tube surface region to the fresh fluid of the main flow region and lasts over long distances. Moreover, the longitudinal vortices restrain unsteady transverse vortex shedding. As a result, heat transfer rate for the flat tube with VG case is larger compared to that without VG case. From the view point of pressure drop, increase in pressure drop for the case with VG is not so much larger due to the restraint of transverse vortex shedding. Finally, heat transfer performance becomes higher for the flat tube with VG case compared to that without VG case for the same pumping power.

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