Turbulent forced convection in a heat exchanger square channel with wavy-ribs vortex generator

Boonloi, Amnart; Jedsadaratanachai, Withada

doi:10.1016/j.cjche.2015.04.001

Cited by 18 publications

(8 citation statements)

References 31 publications

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“…The comparison of the thermal enhancement factors of this work with those of the previous researches, such as wavy rib, 35 discrete combined baffle, 36 V-baffle, 37 and discrete-full baffle, 38 is presented in Figure 18. It is found that the wavy V-rib gives higher thermal performance than the other turbulators when considered at Re = 3000.…”

Section: Resultsmentioning

confidence: 97%

Performance analysis and flow visualization in a round tube heat exchanger inserted with wavy V-ribs

Jedsadaratanachai

Boonloi

2017

Advances in Mechanical Engineering

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This article presents thermal performance analysis, flow visualization, and heat transfer characteristic in a round tube heat exchanger inserted with wavy V-rib. The novel design of the wavy V-rib not only allows mass production and simple installation in the heating system but also remains the thermal performance and the heat transfer rate as near as those of the V-baffle design. The numerical investigation with finite volume method is selected to study and describe the mechanisms in the test section. The effects of rib thickness, rib height, and flow direction are considered for the turbulent regime. The numerical results are reported in terms of flow structure and heat transfer behavior. The relationship of the Nusselt number, friction factor, and thermal enhancement factor with various parameters is also concluded. The numerical results reveal that the optimum thermal performance is detected for the wavy V-rib at b/D around 0.1-0.15, while the optimal t/D is around 0.15-0.20 when considered at the simplicity of the wavy V-rib production.

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Section: Resultsmentioning

confidence: 97%

Performance analysis and flow visualization in a round tube heat exchanger inserted with wavy V-ribs

Jedsadaratanachai

Boonloi

2017

Advances in Mechanical Engineering

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“…The maximum performance enhancement criteria (PEC) of 1.41 were achieved from DWVG class 4 vortex generator. Wavy-ribs vortex generator (VG) by Withada [4] proved to be one of the augmented method in heat exchanging system with a maximum PEC factor of 1.47-1.52 at Re 3000 for 30 0 and 45 0 ribs.…”

Section: Introductionmentioning

confidence: 99%

Numerical Evaluation of Thermo-Hydraulic Performance Index of a Double Pipe Heat Exchanger Using Double Sided Louvered Winglet Tape

Thejaraju

Girisha²,

Manjunath³

et al. 2020

Journal of Thermal Engineering

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The decade has witnessed great importance of numerical techniques for scientists and researchers in deciding the correctness, stability, and reliability of new designs. In the present study a numerical technique has been implemented to investigate the thermo-hydraulic performance of the Louvered winglet tape inside the tube section of the double pipe heat exchanger. The Louvered winglet tape has been examined with the slope angle of 50, 100, 150 and 210 to study their thermal characteristics. The Reynolds number 4000-30000 was examined on slope angle of 50, 100, 150 and 210 to study their flow characteristics in the turbulent domain. A smooth pipe was examined to evaluate heat transfer characteristics in terms of Nusselt number and friction coefficient over augmented tube with Louvered winglet tape. The results show a satisfactory performance of Louvered winglet tape over the smooth tube with a similar trend of friction factor, Nusselt number, and thermo-hydraulic performance index (THPI). The percentage of increment of the Nusselt number of the results is found to be 237.04%, 258.4%, 275.11%, and 289.72% when compared to smooth pipe with respect to slope angle of 50, 100, 150 and 210, respectively. The amount of increase in the friction factor in comparison with plain tube is 5.13, 6.73, 8.33, and 11.73 times of that of smooth pipe with respect to slope angle of 50, 100, 150 and 210, respectively. The Louvered winglet tape with slope angle 150 has shown to be promising with respect to higher THPI when considering with other slope angle of 50, 100, and 210. The maximum THPI of 1.85 was obtained for slope angle 150 at Re 12000. Similarly, the THPI values for other slope angle 50, 100, and 210 are 1.71, 1.78 and 1.69. In addition to better performance the Louvered winglet tape can be easily fabricated and adapted for a wide variety of heat transfer industries.

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“…Consequently, an optimal design strategy would achieve the highest heat transfer possible with the lowest pressure drop within the system (i.e., the best thermal enhancement factor (TEF)). TEF refers to the ratio of convective heat transfer within the flow channels with enhanced heat transfer surfaces and the convective heat transfer of smooth surface channels under a condition of similar pump power [12]. most volume of the turbine blades, has various flow channels and requires enhanced surface cooling through the use of ribs, dimpled surfaces, and surfaces with arrays of protrusions and rough surfaces.…”

Section: Introductionmentioning

confidence: 99%

“…Consequently, an optimal design strategy would achieve the highest heat transfer possible with the lowest pressure drop within the system (i.e., the best thermal enhancement factor (TEF)). TEF refers to the ratio of convective heat transfer within the flow channels with enhanced heat transfer surfaces and the convective heat transfer of smooth surface channels under a condition of similar pump power [12]. Research regarding enhanced heat transfer by rib turbulators and their associated pressure drop in single channels or multi-pass channels has examined experimental parameters, such as the relative roughness pitch (P/e), relative roughness height (e/H or e/Dh), angle of attack (α), and modified shapes.…”

Section: Introductionmentioning

confidence: 99%

Influence of Geometric Parameters of Alternate Axis Twisted Baffles on the Local Heat Transfer Distribution and Pressure Drop in a Rectangular Channel Using a Transient Liquid Crystal Technique

2019

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This paper reports the effects of alternate axis twisted baffle geometric parameters on the heat transfer and flow characteristics within rectangular channels. In our experiments we used modified shapes of alternate axis twisted baffles according to relative pitch ratios (s/w) equal to 2–12 and twist ratios (y/w) equal to 1–5, under conditions where the angle of attack (α) was 90° and the relative blockage height (e/Dh) was at a constant value of 0.095. The results for the Reynolds numbers based on the duct hydraulic diameter ranged from 9000 to 24,000 at a constant Prandtl number, Pr = 0.707, using air as a working fluid. A 0.05 mm thick stainless-steel foil was used as a heater, and a thermochromic liquid crystal technique was used to obtain the local temperature distribution on the heated surfaces. Images were captured in areas with periodic, fully developed regions in the channel. The results show that rectangular channels equipped with alternate axis twisted baffles demonstrated 80%–185% greater heat transfer than rectangular channels with no baffles. Channels with alternate axis twisted baffles at higher twist ratios (y/w) and smaller relative pitch ratios (s/w) showed increased heat transfer, as well as pressure loss within the system, compared with other types of twisted baffles. The thermal enhancement factor of the rectangular channels equipped with alternate axis twisted baffles was higher than that for transverse baffles and smooth channels under similar operating conditions.

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Turbulent forced convection in a heat exchanger square channel with wavy-ribs vortex generator

Cited by 18 publications

References 31 publications

Performance analysis and flow visualization in a round tube heat exchanger inserted with wavy V-ribs

Performance analysis and flow visualization in a round tube heat exchanger inserted with wavy V-ribs

Numerical Evaluation of Thermo-Hydraulic Performance Index of a Double Pipe Heat Exchanger Using Double Sided Louvered Winglet Tape

Influence of Geometric Parameters of Alternate Axis Twisted Baffles on the Local Heat Transfer Distribution and Pressure Drop in a Rectangular Channel Using a Transient Liquid Crystal Technique

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