Simultaneous heat transfer enhancement and pressure loss reduction for finned-tube bundles with the first or two transverse rows of built-in winglets

Kwak, Kyung Min; Torii, Kahoru; Nishino, Koichi

doi:10.1016/j.expthermflusci.2004.08.005

Cited by 68 publications

(22 citation statements)

References 10 publications

(38 reference statements)

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“…15.The heat transfer coefficient decreased by 16.8%, 15.5% and 12.1% for base length 35mm, 30mm and 20mm respectively when compared to plain fin. Figure 16 and 17 also further verify the same results and thus signify that as the length of the winglet increases, the winglets become a longer obstruction and decelerate the flow towards the next consecutive winglets, which is the reason of enhanced heat transfer, Kwak et al, 2005. Although a further increment in length will further help improve the heat transfer but at the cost of higher pressure drop penalty, which is undesirable as a higher pressure drop will require more energy for the flow to take place.…”

Section: Fig 13supporting

confidence: 62%

“…And hence taking into account the pressure drop, the distance and an increment of heat transfer from the previous angle, the angle of attack of 30 o is best suited for further analysis. Figure 12 and 13 shows the comparison of current work with the work of Kwak et al, (2005), which was based on using two rows of winglets as compared to current work of using three rows of winglets in staggered arrangement. The heat transfer enhancement increases significantly with three rows of winglets as the wake region is affected and the zone of poor heat transfer decreases behind all the three rows of the tubes.…”

Section: Fig 13mentioning

confidence: 99%

“…While carrying out the experiment amongst all the cases, the maximum value for local heat transfer coefficient was observed at the winglet position ∆x = 0.5D, ∆y = 0.5D which gave an increase of average Nusselt number of 46.64% and increase in pressure drop of 18.07%. Kwak et al (2005), performed an experiment on heat transfer enhancement and pressure loss penalty caused by a single row of winglets built in the first transverse row of tubes, and comparing it between ''common flow up'' (''toe-out'') and ''common flow down'' (''toe-in'') winglet configurations. The results on experimenting were that the heat transfer enhancement for two rows of winglets became slightly higher by 6-15% in a whole range of Reynolds number than for a single front row of winglets.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Numerical Study of Fin-Tube Type Heat Exchanger With Delta Winglets

Pal¹,

Majumder²

2016

Frontiers in Heat and Mass Transfer

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Section: Fig 13supporting

confidence: 62%

Section: Fig 13mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical Study of Fin-Tube Type Heat Exchanger With Delta Winglets

Pal¹,

Majumder²

2016

Frontiers in Heat and Mass Transfer

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“…Overall, the three-row coil performed best with a 30-10% augmentation in heat transfer and a reduction of 55-34% in the pressure drop for Reynolds number ranging from 350 to 2100. Kwak et al (2005) carried forward their study and performed experiments to study the common flow up configuration of the DWP with two rows of DWP placed in a three row platefinned-tube heat exchanger. The geometric parameters were the same as were in the previous study (Torii et al 2002).…”

Section: 2c Fins With Vortex Generatorsmentioning

confidence: 99%

A review on the thermal hydraulic characteristics of the air-cooled heat exchangers in forced convection

Kumar

Joshi

Nayak

et al. 2015

Sadhana

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In this paper, a review is presented on the experimental investigations and the numerical simulations performed to analyze the thermal-hydraulic performance of the air-cooled heat exchangers. The air-cooled heat exchangers mostly consist of the finned-tube bundles. The primary role of the extended surfaces (fins) is to provide more heat transfer area to enhance the rate of heat transfer on the air side. The secondary role of the fins is to generate vortices, which help in enhancing the mixing and the heat transfer coefficient. In this study, the annular and plate fins are considered, the annular fins are further divided into four categories: (1) plane annular fins, (2) serrated fins, (3) crimped spiral fins, (4) perforated fins, and similarly for the plate fins, the fin types are: (1) plain plate fins, (2) wavy plate fins, (3) plate fins with DWP, and (4) slit and strip fins. In Section 4, the performance of the various types of fins is presented with respect to the parameters: (1) Reynolds number, (2) fin pitch, (3) fin height, (4) fin thickness, (5) tube diameter, (6) tube pitch, (7) tube type, (8) number of tube rows, and (9) effect of dehumidifying conditions. In Section 5, the conclusions and the recommendations for the future work have been given.

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“…Ribs [ 3] are well known as good manners. But the machine production on surface of tubes and fin is necessary for them.…”

Section: Introductionmentioning

confidence: 99%

Heat transfer enhancement of a single row of tube

Tsutsui

2017

EPJ Web Conf.

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Abstract.A rod was positioned upstream of a circular cylinder to enhance its heat transfer and reduce its drag in air stream. The results are increasing the overall heat transfer by 40% over and reducing the drag by 30% the value for a single circular cylinder. In the present, this technique applied to a single row of tubes. Heat transfer enhancement and drag reduction are important factor for multi-tube heat exchanger. The present study investigated the heat transfer and surface pressure characteristics of each tube for single row of tubes under various numbers of tubes, pitch and Reynolds number. The tube diameter, D, was 20 mm, and the rod diameter was 5 mm. The distance between the center axes of the rod and the tube was 30mm.The Reynolds number based on D ranged from 5.3×10 3 to 2.1×10 4 . The result is that this technique is effective for heat transfer enhancement and drag reduction of row of tube.

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Simultaneous heat transfer enhancement and pressure loss reduction for finned-tube bundles with the first or two transverse rows of built-in winglets

Cited by 68 publications

References 10 publications

Numerical Study of Fin-Tube Type Heat Exchanger With Delta Winglets

Numerical Study of Fin-Tube Type Heat Exchanger With Delta Winglets

A review on the thermal hydraulic characteristics of the air-cooled heat exchangers in forced convection

Heat transfer enhancement of a single row of tube

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