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.

Study on Heat Transfer Performance Affected by Structural Parameters of Multi-Channel Cylinder Dryer

2016 ◽  
Author(s):  
Yan Yan ◽  
Dong Jixian ◽  
Tang Wei ◽  
Feng Shiyuf
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Aspect Ratio ◽  
Transfer Coefficient ◽  
Heat Transfer Performance ◽  
Flow Characteristic ◽  
Structural Parameters ◽  
Transfer Performance ◽  
Spacing Ratio ◽  
Condensing Heat Transfer

An approach to design multi-channel cylinder dryer was proposed. The heat transfer performance and flow characteristic under various structural parameters were analyzed. First, an experiment was designed and set up to measure the condensing heat transfer coefficient and the pressure drop in order to verify the applicability of the Cavallini’s correlation. Then, the relationship among the count of channels, aspect ratio, spacing ratio, width, height and hydraulic diameter of a channel was given. Finally, the correlation of condensing heat transfer and the homogeneous model were introduced in order to observe the heat transfer performance and flow characteristic of the multi-channel cylinder dryer affected by different structures. The study reveals that the structural parameters including count of channels, aspect ratio, spacing ratio of a channel dramatically influence the condensation heat transfer coefficient and frictional resistance of the steam. Based on the selected paper machine, it is suggested that the overall performance of the multi-channel cylinder dryer is best if the count of channels is 150–200, the aspect ratio is 1:3 and the spacing ratio is 1:1–1:3.

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

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