Impact of Blockage Ratio on Thermal Performance of Delta-Winglet Vortex Generators

Yaningsih, Indri; Wijayanta, Agung Tri; Miyazaki, Takahiko; Koyama, Shigeru

doi:10.3390/app8020181

Cited by 20 publications

(10 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…e double-side winglet integrated twisted tapes raise the Nusselt number by 269% and improve the performance by 10.1 times as compared with plain tube [39,40]. Veerabhadrappa Bidari et al [41] modified the turbulators for heat exchangers by punched delta winglet vortex shapes and improved thermo-hydraulic performance by 1.22 times as compared with other systems.…”

Section: Introductionmentioning

confidence: 99%

Genetic Algorithm Integrated Fuzzy AHP-VIKOR Approach for the Investigation of W-Cut Insert Heat Exchanger for Cooling of Dielectric Fluid Used in Ultra-High Voltage Transformer

Gowri

Isaac

Muralikrishna

et al. 2022

Advances in Materials Science and Engineering

View full text Add to dashboard Cite

This study proposes a novel W-cut twisted tape to evaluate and enhance the effectiveness of novel grooved tube heat exchanger. The experimental investigations are carried out with W-cut inserts, which possess two main control factors, namely, twist tape ratio (y = 3.5 to 6.5) and width tape ratio (WR = 0.43 to 0.6). The investigation results prove that in all cases the energy transmission and friction factor of W-cut insert along with the first law and second law efficiency are considerably higher than the conventional tube arrangement. The empirical model equations for friction factor, performance enhancement ratio, Nusselt number, and rational efficiency are developed, and they show good affinity with experimental data. Since the abovementioned factors have conflicting terms, it is essential to select the proper operating configuration of the heat exchanger in order to increase the thermal energy transfer rate with reduced consumption of pumping energy. The multi-objective genetic algorithm (GA) tool is used to identify the optimum operating conditions. Further, the hybrid multi-criteria decision-making model, FAHP-VIKOR, is applied to select the perfect model from the set of non-dominated solution. The ranking of alternatives is as follows: A4 > A11 > A2 > A9 > A21 > A17 > A1 > A24 > A11 > A23 > A7 > A18 > A13 > A10 > A20 > A5 > A19 > A14 > A16 > A22 > A25 > A6 > A15 > A3 > A8. The optimized configuration of W-cut insert is compared with the former inserts, and the optimal configuration exhibits supreme performance than other inserts.

show abstract

Section: Introductionmentioning

confidence: 99%

Genetic Algorithm Integrated Fuzzy AHP-VIKOR Approach for the Investigation of W-Cut Insert Heat Exchanger for Cooling of Dielectric Fluid Used in Ultra-High Voltage Transformer

Gowri

Isaac

Muralikrishna

et al. 2022

Advances in Materials Science and Engineering

View full text Add to dashboard Cite

show abstract

“…Numerous research studies have been performed on heat exchangers, to enhance the heat transfer, in order to achieve a higher heat exchange performance [1,2]. For this purpose, the following efforts have been reported in our previous works: a direct contact system for adsorption cycle [3][4][5], using nanofluid as the working fluid [6,7]; improvement of maldistribution inside the distributor of heat exchangers [8][9][10]; using inserts inside the tubes [11][12][13][14][15]. Based on the published reports, it is known that the investigations on passive heat transfer enhancement methods using various inserts do not consider the existing problems.…”

Section: Introductionmentioning

confidence: 99%

Internal Flow in an Enhanced Tube Having Square-cut Twisted Tape Insert

et al. 2019

Self Cite

View full text Add to dashboard Cite

In this study, a numerical simulation has been conducted in order to evaluate the thermal hydraulic performance of a turbulent single-phase flow inside an enhanced tube equipped with a square-cut twisted tape (STT) insert. The classical twisted tape (CTT) insert was also investigated for comparison. The k-ε renormalized group turbulence model has been utilized as the turbulent model. Various twist ratios (y/W) of 2.7, 4.5, and 6.5 were investigated for the Reynolds number range of 8000–18,000, with water as the working fluid. The numerical results indicated that, in comparison with the plain tube (PT), the tube equipped with the STT with the twist ratios of 2.7, 4.5, and 6.5 led to an increase in the values of the Nusselt number and friction factor in the inner tube by 45.4–80.7% and 2.0–3.3 times, respectively; in addition, the highest thermal performance of 1.23 has been obtained. The results further indicated that the tube equipped with the CTT of the same twist ratios improved the Nusselt number and friction factor in the inner tube by 40.3–74.4% and 1.7–3.0 times, respectively, in comparison with the PT; further, the maximum thermal performance of 1.18 was achieved.

show abstract

“…Several works are summarized hereafter. The passive heat transfer enhancement methods that are still used by the majority of researchers are swirl devices in the form of twisted tape [3][4][5], wire coil [6,7], helical screw [8,9], and vortex generators in the form of a winglet [10][11][12]. These were investigated under various parameters to determine the important factors that affect the performance of the heat exchanger.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Heat Transfer Enhancement of Internal Flow Using Double-Sided Delta-Winglet Tape Insert

et al. 2018

Self Cite

View full text Add to dashboard Cite

A numerical study was performed to investigate the thermal performance characteristics of an enhanced tube heat exchanger fitted with punched delta-winglet vortex generators. Computational fluid dynamics modeling was applied using the k–ε renormalized group turbulence model. Benchmarking was performed using the results of the experimental study for a similar geometry. Attack angles of 30°, 50°, and 70° were used to investigate the heat transfer and pressure drop characteristics of the enhanced tube. Flow conditions were considered in the turbulent region in the Reynolds number range of 9100 to 17,400. A smooth tube was employed for evaluating the increment in the Nusselt number and the friction factor characteristics of the enhanced tube. The results show that the Nusselt number, friction factor, and thermal performance factor have a similar tendency. The presence of this insert offers a higher thermal performance factor as compared to that obtained with a plain tube. Vortex development in the flow structure aids in generating a vortex flow, which increases convective heat transfer. In addition, as the angle is varied, it is observed that the largest attack angle provides the highest thermal performance factor. The greatest increase in the Nusselt number and friction factor, respectively, was found to be approximately 3.7 and 10 times greater than those of a smooth tube. Through numerical simulations with the present simulation condition, it is revealed that the thermal performance factor approaches the value of 1.1. Moreover, the numerical and experimental values agree well although they tend to be different at high Reynolds number conditions. The numerical and experimental values both show similar trends in the Nusselt number, friction factor, and thermal performance factor.

show abstract

Impact of Blockage Ratio on Thermal Performance of Delta-Winglet Vortex Generators

Cited by 20 publications

References 26 publications

Genetic Algorithm Integrated Fuzzy AHP-VIKOR Approach for the Investigation of W-Cut Insert Heat Exchanger for Cooling of Dielectric Fluid Used in Ultra-High Voltage Transformer

Genetic Algorithm Integrated Fuzzy AHP-VIKOR Approach for the Investigation of W-Cut Insert Heat Exchanger for Cooling of Dielectric Fluid Used in Ultra-High Voltage Transformer

Internal Flow in an Enhanced Tube Having Square-cut Twisted Tape Insert

Numerical Study of Heat Transfer Enhancement of Internal Flow Using Double-Sided Delta-Winglet Tape Insert

Contact Info

Product

Resources

About