Heat transfer enhancement of internal flow by inserting punched delta winglet vortex generators with various attack angles

Wijayanta, Agung Tri; Istanto, Tri; Kariya, Keishi; Miyara, Akio

doi:10.1016/j.expthermflusci.2017.05.002

Cited by 83 publications

(22 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A downtrend in f corresponds to an increase in Re number for all test conditions. These results are consistent with those reported in the authors' earlier publications [16,23,24]. As shown in Figure 7, the friction factor of the tube with DWT or LS insertions is higher than with the plain tube.…”

Section: Effect Of Blockage Ratio On Friction Factorsupporting

confidence: 83%

“…This phenomenon significantly improved Figure 6 depicts the behavior of convective heat transfer in the value of Nusselt number (Nu) plotted against Reynolds number (Re) at the value of Rb = 0.28, 0.35, and 0.42 compared with LS and plain tube. Figure 6 shows that Nu increases as Re increases and confirms the results of our previous studies [16,23,24]. An increase in mean velocity, which increases the Re, leads to intensification of the turbulence, thereby improving temperature gradients.…”

Section: Validation Of the Plain Tubesupporting

confidence: 78%

“…In this work, the VGs are installed in liquid to liquid heat exchanger to cover the application by using the different of working fluids. This present study is a continuation of our previous work [16]. Modification of the geometrical structure of the double-sided delta-winglet tape (DWT) VGs in term of attack angle has been experimentally examined.…”

Section: Introductionmentioning

confidence: 58%

“…When the winglet is punched out, it will create an attack angle between the wing/winglet with the remaining strip/base fin. Based on our previous study [16], the values of the attack angle (α = 70°), winglet-pitch (p = 15 mm), and winglet width (c = 8 mm) were kept constant. The winglet heights (b) of the DWTs were 4, 5, and 6 mm, giving a blockage ratio (Rb = b/di) of 0.28, 0.35, and 0.42, respectively.…”

Section: Data Reduction Equationsmentioning

confidence: 99%

“…When the winglet is punched out, it will create an attack angle between the wing/winglet with the remaining strip/base fin. Based on our previous study [16], DWTs and LSs were fabricated using aluminum with the following dimensions: 0.7 mm in thickness, 12.6 mm in width (W), and 2000 mm in length (L). The DWTs are a modification of the LS with winglets punched out at the vertical center of the strip and made to protrude either upward or downward in an alternating fashion at a certain attack angle with respect to the strip base.…”

Section: Data Reduction Equationsmentioning

confidence: 99%

See 4 more Smart Citations

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

et al. 2018

View full text Add to dashboard Cite

Abstract:The impact of double-sided delta-winglet tape (DWTs) inserts on convective heat transfer and friction behaviors in a tube was experimentally investigated. Three DWTs with ratios of winglet-height (b) to inner tube diameter (d i ) called blockage ratio (R b ) of 0.28, 0.35 and 0.42 were tested and their performance was compared to that of a longitudinal strip and plain tube under similar test flow conditions. Experiments were conducted over a wide range of flow rates, 3.35 × 10 −5 -8.33 × 10 −5 m 3 /s, which correspond to 5500 ≤ Reynolds number (Re) ≤ 14,500 in the 14.3 mm i.d. tube. The results revealed that using DWTs dramatically increased the Nusselt number (Nu) by as much as 364.3% and the friction factor (f ) by 15.5 times compared with those of a plain tube. Thermal performance (η) increased with a corresponding increase in R b . The highest thermal performance (η) obtained was 1.4. Showing a notable improvement on the thermal performance of the system, DWTs are proposed as a favorable insert device.

show abstract

Section: Effect Of Blockage Ratio On Friction Factorsupporting

confidence: 83%

Section: Validation Of the Plain Tubesupporting

confidence: 78%

Section: Introductionmentioning

confidence: 58%

Section: Data Reduction Equationsmentioning

confidence: 99%

Section: Data Reduction Equationsmentioning

confidence: 99%

See 3 more Smart Citations

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

et al. 2018

View full text Add to dashboard Cite

show abstract

Thermal and hydraulic characteristics of a triangular duct using an Al₂O₃ nanofluid in a turbulent flow regime

Taamneh

Kabeel

Prakash

et al. 2019

Heat Trans. Asian Res.

View full text Add to dashboard Cite

This paper presents the computational analysis of convective heat transfer characteristics, pressure drop, and entropy generation characteristics of Al2O3/water nanofluids in a noncircular duct (triangular) using a single phase approach under a turbulent flow regime. The thermal and pressure drop characteristics of different concentrations of Al2O3 nanoparticles (NPs) and the analysis were carried out in Fluent software using a k‐ε approach under constant wall heat flux around the boundary. The results show that there is an increase in pressure drop and thereby an increase in friction by 20% for the smooth condition. The total pressure drop between the entry and exit section of the duct is increased to approximately 84.2% and 85.6% for a higher Reynolds number (Re = 10 000) compared with that of base fluid. Similarly, the entropy generation of water is increased by 40% as compared with 0.05% and 0.1% Al2O3 NPs. There is also a decrease in entropy generation identified while there is an increase in the Reynolds number. The convective heat transfer of 0.05% and 0.1% nanofluid has a similar trend with increased Reynolds number. The maximum performance is observed at the Reynolds number (Re = 4000) and found to be 1.29 for 0.1% concentration, whereas, the fluid at 0.05% is observed to be at 1.23. At a higher Reynolds number (Re = 10 000) the performance index decreased to approximately 1.19 and 1.25 for 0.05% and 0.1%, respectively.

show abstract

Investigation of heat transfer augmentation in a horizontal tube using different rectangular cut ring inserts

2023

View full text Add to dashboard Cite

Experimental and computational investigations have studied the heat transfer, friction factor, and enhancement of heat transfer in a horizontal tube equipped with rectangular cut ring inserts and different diameter ratios (D/d) and pitch-to-tube diameter ratios (p/d t ). In the present study, air having a Reynolds no. range of 6700-20,100 was used as a working fluid. Three diameter ratios (D/d) were considered experimentally and numerically as 1.2, 1.25, and 1.3, and the pitch-totube diameter ratio (p/d t ) was (1, 0.625, and 0.5). Air was forced as working fluid through the tube and a uniform heat flux of 2000, 3500, and 5000 W/m 2 was applied through the tube's exterior surface. On the basis of the turbulence model k-ɛ with various parameters, three-dimensional numerical simulations using the ANSYS Fluent software 17.2 were investigated. Under the same working conditions, the results manifested a higher heat transfer rate and friction factor as compared to the plain tube. The results evinced that the Nusselt number for a horizontal tube equipped with rectangular cut ring inserts having various pitch ratios and diameter ratios is discovered to be higher than that for the plain tube. With the increased ring spacing, the overall improvement in heat transfer occurred. And, with a rise in Re, the total

show abstract

Heat transfer enhancement of internal flow by inserting punched delta winglet vortex generators with various attack angles

Cited by 83 publications

References 21 publications

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

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

Thermal and hydraulic characteristics of a triangular duct using an Al₂O₃ nanofluid in a turbulent flow regime

Investigation of heat transfer augmentation in a horizontal tube using different rectangular cut ring inserts

Contact Info

Product

Resources

About

Heat transfer enhancement of internal flow by inserting punched delta winglet vortex generators with various attack angles

Cited by 83 publications

References 21 publications

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

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

Thermal and hydraulic characteristics of a triangular duct using an Al2O3 nanofluid in a turbulent flow regime

Investigation of heat transfer augmentation in a horizontal tube using different rectangular cut ring inserts

Contact Info

Product

Resources

About

Thermal and hydraulic characteristics of a triangular duct using an Al₂O₃ nanofluid in a turbulent flow regime