Effect of winglet location on performance of fin-tube heat exchangers with inline tube arrangement

Naik, Hemant; Tiwari, Shaligram

doi:10.1016/j.ijheatmasstransfer.2018.04.071

Cited by 44 publications

(14 citation statements)

References 36 publications

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“…However, the swirl flow (longitudinal vortices) generated by a pair of VGs was found to weaken in the downstream direction. The longitudinal vortices could not last long under the recirculation effect of the flow behind the tube [9]. This problem was solved by adding VG pairs.…”

Section: Velocity Streamline and Vectormentioning

confidence: 99%

“…Many scholars have tried to increase the convective heat transfer coefficient using a VG. Through three-dimensional (3D) modeling, Naik and Tiwari [9] studied the effect of winglet locations on heat transfer features in fin and tube heat exchangers using inline RWPs, and observed that the Nusselt number (Nu) and secondary flow intensity (Se) peaked at ∆Y = ± 1.25 and attack angle (β) = 45°, which are mounted in the downstream area adjacent to the tube. Lu and Zhai [10] numerically analyzed the heat transfer and pressure drop on a fin and oval tube heat exchanger using a tear-drop delta VG, found that the tear-drop delta GV outperforms plain delta VG, and investigated the mechanism of the advantage in the light of Se and field synergy principle.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Attack Angle of Concave and Convex Winglets Vortex Generators on Thermal-Hydraulic Performance of Fin and Tube Heat Exchangers with Field Synergy Principle

Syaiful¹,

Yunianto²,

Salsabila³

et al. 2021

IJHT

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In fin and tube heat exchangers, the gas passing through the fin has a lower thermal conductivity than the fluid passing through the tube. The low thermal conductivity brings a high thermal resistance, which suppresses the heat transfer rate. A common practice to enhance fin-side heat transfer is to generate longitudinal vortex by mounting vortex generators (VGs) on the fin. This paper aims to investigate how longitudinal vortex generator (LVG) improves heat transfer and pressure drop. Numerical simulations were carried out to analyze three types of VGs. The installation of VGs was varied with the attack angle changing from 10°, 15°, to 20° with a 1-3-4-7 VG arrangement on the tube. The flow velocity was expressed in Reynolds number (Re) between 364 and 689. The enhancement of heat transfer rate and improvement of pressure drop were analyzed between three types of VG, three different attack angles, and four types of winglet installation, compared to baseline. The simulation results show that the highest convective heat transfer coefficient (84.85%) was achieved by the VG composed of seven concave delta winglet pairs (CDWPs) at the attack angle of 20° and Re = 689; CDWP VG provides the highest heat transfer improvement among all cases.

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Section: Velocity Streamline and Vectormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Attack Angle of Concave and Convex Winglets Vortex Generators on Thermal-Hydraulic Performance of Fin and Tube Heat Exchangers with Field Synergy Principle

Syaiful¹,

Yunianto²,

Salsabila³

et al. 2021

IJHT

View full text Add to dashboard Cite

show abstract

“…An obvious difference in Nu s exists between c 4 and c 7 . Since the common flow region is beneficial to heat transfer [17], the local value of Nu s generally increases in the short region behind the winglets, and the region length with a large value of Nu s decreases, with c changing from c 4 to c 6 . This is because the interaction between the vortices increases with c changing from c 4 to c 6 , and the intensity of the vortices attenuates rapidly in the downstream region.…”

Section: Distributions Of the Span-average Values Of Se S And Nu Smentioning

confidence: 99%

“…[16] experimentally studied a fin with radiantly arranged VGs and showed that the fin with the radiantly-arranged VGs had a better 2 of 14 comprehensive performance than the studied wavy fin. Naik and Tiwari [17] studied the location of VGs in the CFD configuration and reported that heat transfer is the highest for the VGs located in the adjacent region.…”

Section: Introductionmentioning

confidence: 99%

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

2020

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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.

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“…It should be noted that this principle is frequently considered in industrial heat exchanger designs using various shapes, such as fin, baffle, vortex generator and so forth, to increase heat transfer efficiency [25][26][27][28][29][30][31][32][33][34]. The key point in this heat exchanger design is to take into consideration both the negative aspect of increased flow resistance that arises from the installation of the obstacle and the positive aspect of heat transfer enhancement to the vortex as mentioned above.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on the Effects of Baffles with Various Thermal and Geometrical Conditions on Thermo-Fluid Dynamics and Kinetic Power of a Solar Updraft Tower

2018

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Solar updraft towers (SUTs) are used for renewable power generation, taking advantage of the thermal updraft air flow caused by solar energy. Aerodynamic devices have been applied to SUTs to improve their performance and the baffle is one such device. Here, we investigate the effect of baffle installation on the thermo-fluid dynamic phenomena in the collector of an SUT and how it enhances the overall SUT performance using computational fluid dynamics analysis. Two geometric parameters (height and width of baffle) and two thermal boundary conditions of the baffle (adiabatic condition and heat flux condition) were tested through simulations with 10 different models. The vortex generated by the baffle has a positive effect on the delivery of heat energy from the ground to the main flow; however, one disadvantage is that the baffle inherently increases the resistance of the main flow. Over 3% higher kinetic power was achieved with some of the simulated baffle models. Therefore, an optimum design for baffle installation can be achieved by considering the positive and negative thermo-fluid dynamics of baffles.

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Effect of winglet location on performance of fin-tube heat exchangers with inline tube arrangement

Cited by 44 publications

References 36 publications

Effect of Attack Angle of Concave and Convex Winglets Vortex Generators on Thermal-Hydraulic Performance of Fin and Tube Heat Exchangers with Field Synergy Principle

Effect of Attack Angle of Concave and Convex Winglets Vortex Generators on Thermal-Hydraulic Performance of Fin and Tube Heat Exchangers with Field Synergy Principle

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

Numerical Investigation on the Effects of Baffles with Various Thermal and Geometrical Conditions on Thermo-Fluid Dynamics and Kinetic Power of a Solar Updraft Tower

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