scholarly journals Characteristics of Flow Symmetry and Heat Transfer of Winglet Pair in Common Flow Down Configuration

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 209 ◽  
Author(s):  
KeWei Song ◽  
WeiNa Shi ◽  
Xiang Wu ◽  
LiangBi Wang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Performance ◽  
Flow Region ◽  
Vortex Generators ◽  
Transfer Performance ◽  
Vortex Interaction ◽  
Longitudinal Vortices ◽  
Delta Winglet ◽  
The Common ◽  
Flow Symmetry

The effect of transverse pitch between a pair of delta-winglet vortex generators arranged in a common flow down configuration on the symmetrical flow structure and heat-transfer performance was numerically investigated. The results showed that symmetrical longitudinal vortices form a common flow down region between the vortices. The fluid is induced to flow from the top towards the bottom of the channel in the common flow region, which is advantageous to the heat transfer of the bottom fin. The vortex interaction increases and the vortex intensity decreases along with the decrease in transverse pitch of vortex generators. Vortex interaction has a slight influence on pressure penalty. The Nusselt number decreases with increasing vortex interaction. The vortices gradually attenuate and depart from each other during the process of flowing downward. A reasonable transverse pitch of delta-winglet vortex generators in a common-flow-down configuration is recommended for high thermal performance.

scholarly journals Flow Symmetry and Heat Transfer Characteristics of Winglet Vortex Generators Arranged in Common Flow up Configuration

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 247 ◽  
Author(s):  
Kewei Song ◽  
Lu Wang ◽  
Yajun Hu ◽  
Qi Liu
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Flow Region ◽  
Vortex Generators ◽  
Heat Transfer Characteristics ◽  
Longitudinal Vortices ◽  
The Common ◽  
Flow Symmetry

The generation of longitudinal vortices is an effective method for promoting thermal performance with a relative low-pressure penalty in heat exchangers. The winglet pair can generate symmetrical longitudinal vortices on the cross-section of the channel. The heat transfer and pressure-loss characteristics of a pair of winglet vortex generators with different transverse pitches are numerically studied in this paper. The winglet pair arranged in a common flow up configuration generates a pair of symmetrical longitudinal main vortices with counter-rotating directions. The symmetrical flow structure induces fluid to flow from the bottom towards the top of the channel in the common flow region between the longitudinal vortices. The flow symmetry of the longitudinal vortices and the heat transfer performance are strongly affected by the transverse pitch of the winglet pair owing to the interaction between the longitudinal vortices. The optimal transverse pitch of the studied winglet pair with the best thermal performance is reported. The increments in the vortex intensity and the Nusselt number for the optimal pitch are increased by up to 21.4% and 29.2%, respectively.

scholarly journals Heat Transfer Characteristic on Wing Pairs Vortex Generator using 3D Simulation of Computational Fluid Dynamic

2021 ◽  
Vol 3 (2) ◽  
pp. 215-224
Author(s):  
Petrus Setyo Prabowo ◽  
◽  
Stefan Mardikus ◽  
Ewaldus Credo Eukharisto ◽  
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamic ◽  
Flow Characteristics ◽  
Vortex Generator ◽  
Transfer Characteristic ◽  
Vortex Generators ◽  
Working Fluid ◽  
Longitudinal Vortices ◽  
Delta Winglet ◽  
Fluid Flow Characteristics

Vortex generators are addition surface that can increase heat transfer area and change the fluid flow characteristics of the working fluid to increase heat transfer coefficient. The use of vortex generators produces longitudinal vortices that can increase the heat transfer performance because of the low pressure behind vortex generators. This investigation used delta winglet vortex generator that was combined with rectangular vortex generator to Reynold numbers ranging 6,000 to 10,000. The parameters of Nusselt number, friction factor, velocity vector and temperature distribution will be evaluated.

Delta Winglet Pairs in the Core of a Pipe and its Effect on Heat Transfer and Flow

2019 ◽  
Author(s):  
Md. Islam ◽  
Z. Chong ◽  
Md. Alam
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Friction Factor ◽  
Flow Behavior ◽  
Experimental Results ◽  
Vortex Generators ◽  
Experimental Investigations ◽  
Longitudinal Vortices ◽  
The Core ◽  
Delta Winglet

Abstract Vortex generators/turbulent promoters generate the longitudinal vortices which introduce the better mixing of the fluid with fluid circulation and enhance heat transfer. In this research, experimental investigations have been carried out to study the effect of delta winglet vortex generator (DWVG) in the core of the pipe on heat transfer and flow behavior. In this experiment, two pairs of delta winglet vortex generators (DWVG) were printed on the upside and downside of the thin plate using 3D printing technology in a ring and then placed in the core of the pipe to generate longitudinal vortices. Middle plate was very thin. The effect of heights (H = 5mm, 10mm, 15mm and 20mm) of DWVG for 10° angle of attack and 15mm spacing between leading edges of VG pairs on heat transfer and pressure drop was studied. The experiments were conducted for a fully developed turbulent flow of air in the range of Reynolds numbers (Re) 5000–25000. The influence of the DWVGs on heat transfer and pressure drop was investigated in terms of the Nusselt number (Nu) and friction factor (f). The experimental results indicate that DWVG in the core of the tube results in a considerable increase in Nu with some pressure penalty. It is found that DWVG increase Nu considerably only when H is over 10mm. Nu increases with Re and H. Friction factor decreases with Re but increase with H. The thermal performance enhancement (TPE) was noticed decreasing with Re. TPE could be obtain up to 1 only when the height is over 10mm for Re ≤ 7500. The experimental results show that the DWVG in the core of the pipe is not a good option to enhance the heat transfer at a higher Re.

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