Thermal performance of a zig-zag channel formed by two wavy fins mounted with vortex generators

Luo, Chao; Song, KeWei; Tagawa, Tetsuya; Xiang, Wei; Wang, Liang-Bi

doi:10.1016/j.ijthermalsci.2020.106361

Cited by 37 publications

(10 citation statements)

References 48 publications

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“…The Re-normalization Group (RNG) k-ε model is applied for the turbulent flow with the near-wall treatment approach of enhanced wall treatment. k and ε are given as below [30][31][32]:…”

Section: Physical Model and Numerical Methodsmentioning

confidence: 99%

Heat Transfer Enhancement in a Novel Annular Tube with Outer Straight and Inner Twisted Oval Tubes

Luo,

Song,

Tagawa

et al. 2020

Symmetry

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The thermal-hydraulic performance in a novel annular tube formed by outer straight and inner twisted oval tubes is numerically investigated. An annular tube formed by two straight oval tubes is also studied for comparison. Inner twisted oval tubes with different aspect ratios and twist ratios are studied. The heat transfer is well improved by the symmetrical secondary flow in the annulus. The Nusselt number generally increases when the inner oval tube becomes flatter and the twists stronger in the studied range of geometrical parameters. The largest Nusselt number Nu of the inner twisted tube increases by 116% while the friction factor f increases by only 46% compared with that of the inner straight tube, and the largest value of the thermal performance factor (JF) can be up to 1.9. Correlations of the Nusselt number and friction factor are proposed for laminar and turbulent flows, and the deviations of the correlations are within ±5% and ±4% for Nu and f, respectively.

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“…The Re-normalization Group (RNG) k-ε model is applied for the turbulent flow with the near-wall treatment approach of enhanced wall treatment. k and ε are given as below [30][31][32]:…”

Section: Physical Model and Numerical Methodsmentioning

confidence: 99%

Heat Transfer Enhancement in a Novel Annular Tube with Outer Straight and Inner Twisted Oval Tubes

Luo,

Song,

Tagawa

et al. 2020

Symmetry

Self Cite

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“…Moreover, Alshare et al 19 investigated dispersing nanofluid and hybrid nanofluid effect on the flow behavior and heat transfer characteristics in a periodic wavy structure; they found out that hybrid nanofluids are superior with respect to the enhancement of heat transfer. Lou et al 20 considered a heat exchanger employing zig‐zag channels equipped with vortex generators and found that the thermal performance is enhanced. The Nusselt number increased by nearly 32% with merely 24% increase in the friction factor at the optimal angle of 60°.…”

Section: Introductionmentioning

confidence: 99%

Computational analysis of the thermal performance of rarefied air flow in V‐shaped microchannels

et al. 2021

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In this study, a computational fluid analysis of a slip flow developing thermally and hydrodynamically in a triangular microchannel has been considered. The wall of the channel is preserved at a fixed temperature. Temperature jump and velocity slip boundary conditions are imposed on the surfaces. The microchannel is constructed from seven triangular‐shaped channels and the angle of the microchannel (θ) is varied from 0° to 40°. Simulations are carried out for 1 ≤ italicRe ≤ 8 , 0 ≤ italicKn ≤ 0.1, and the air is used as a working fluid with variable physical properties. The simulation results show that the triangular microchannel can improve heat transfer as compared with plain microchannels. An optimal θ of 20° is found to provide the best heat transfer at moderate frictional losses. Finally, correlations for the average Nusselt number and the average friction coefficient among all parameters are proposed as follows: trueNu ̅ = 4.015 Re 0.0255 Kn − 0.1 ( normalsin θ ) − 0.0479, trueC f ̅ = 3.71 Re − 1.218 italicKn − 0.296 ( normalsin θ ) − 0.495.

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“…Promvonge et al [4] experimentally used both twisted-tape and winglet-VGs to enhance the thermal performance of a duct of square section. Luo et al [5] combined wavy-type fins and VGs to improve the hydrothermal aspects of heat exchangers. da Silva et al [6] explored two different types of longitudinal VGs, rectangularwinglet and delta-winglet, to augment the heat transfer in a circular-tube solar-collector.…”

Section: Introductionmentioning

confidence: 99%

“…(e) Zig-zag channel with VGs [5] (f) Tube with rectangular-winglet VGs [6] (g) Horizontal plate with rectangular VGs [7] (h) Rectangular channel with miniature cuboid VGs [8] (i) Circular tube with delta winglet VGs [9] (j) Wavy fin with delta winglet VGs [10] (k) Rectangular channel with angled ribs [11] (l) Fin-and-tube heat exchanger with curved VGs [12] (m) Channel with a tetrahedral, full-body VG [13] (n) Radiator with delta-wing VGs [14] (o) Duct with quadruple V-finned twisted tapes [15] (p) Tube with inclined rectangular ribs [16] (q) Channel with a triangular rib [17] Zhai et al [9] conducted a heat transfer experiment to calculate the Nusselt number, friction factor and thermal performance through a circular-tube with delta winglet VGs of various situations. Luo et al [10] proposed a new combination of a different corrugation-angle wavy-type fin and various attack-angle VGs to enhance the overall performance of heat exchangers.…”

Section: Introductionmentioning

confidence: 99%

Impact of Twisted Fins on the Overall Performances of a Rectangular-Channel Air-Heat Exchanger

Maouedj¹,

Youcef²

2020

MMEP

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Details on the hydrothermal behavior of airflows in a horizontal channel heat exchanger are provided in this paper. The exchanger is equipped with twisted fins under a staggered arrangement. The investigations are achieved with the CFD (Computational Fluid Dynamics) method. Turbulent flows are considered with a Reynolds number (Re) in the range [1.2×10 4 -3.6×10 4 ]. The SST k-ω model is selected to describe the turbulent flows. The flow patterns, thermal fields, Nusselt number (Nu) and the skin friction factor (f) are determined for various flow rates. From the calculations, the suggested design of fins allowed a significant improvement in the heat exchange within the device.

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Thermal performance of a zig-zag channel formed by two wavy fins mounted with vortex generators

Cited by 37 publications

References 48 publications

Heat Transfer Enhancement in a Novel Annular Tube with Outer Straight and Inner Twisted Oval Tubes

Heat Transfer Enhancement in a Novel Annular Tube with Outer Straight and Inner Twisted Oval Tubes

Computational analysis of the thermal performance of rarefied air flow in V‐shaped microchannels

Impact of Twisted Fins on the Overall Performances of a Rectangular-Channel Air-Heat Exchanger

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