Influence of regularly spaced quadruple twisted tape elements on thermal enhancement characteristics

Samruaisin, P.; Changcharoen, Wayo; Thianpong, Chinaruk; Chuwattanakul, V.; Pimsarn, Monsak; Eiamsa-ard, Smith

doi:10.1016/j.cep.2018.04.014

Cited by 51 publications

(10 citation statements)

References 32 publications

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“…The TEF [ 28 , 29 ] is given by:

where

and

are the Nusselt and friction of tube absence of DWPVGs, respectively.…”

Section: Model Descriptionmentioning

confidence: 99%

Numerical and Experimental Investigations of Micro Thermal Performance in a Tube with Delta Winglet Pairs

Wang

Zeng

et al. 2021

Micromachines

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In this research, a novel vortex generator (VG) is presented. The experimental and numerical investigations were carried out to study the micro thermal-hydraulic performance in a heated tube. The numerical results showed that the fluid in the core flow region and the near-wall region was fully mixed because of the longitudinal vortices created by the vortex generators. In addition, the experimental results showed that the heat transfer coefficient (h) decreased with the increasing pitch ratio (PR) value, while the friction coefficient exhibited the opposite trend. With the increasing ration angle (RA) numbers, the h values decreased while the f numbers increased. In addition, the maximum and minimum values of the fraction ratio were 1.66 and 4.27, while these values of the Nusselt number ratio were 1.24 and 1.83. The maximum thermal enhancement factor (TEF) was 1.21 when PR = 0.5, RA = 0° and Re = 9090. The heat transfer enhancement mechanism of the vortex generator is explained from the microscopic point of view.

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“…The TEF [ 28 , 29 ] is given by:

where

and

are the Nusselt and friction of tube absence of DWPVGs, respectively.…”

Section: Model Descriptionmentioning

confidence: 99%

Numerical and Experimental Investigations of Micro Thermal Performance in a Tube with Delta Winglet Pairs

Wang

Zeng

et al. 2021

Micromachines

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show abstract

“…Also, the rate of entropy generation in heated pipe was lower than smooth pipe in utmost cases. Verma et al, 30 Samruaisin et al, 31 Saysroy et al, 32 Xie et al, 33 and Jeong et al 34 observed the influences of inserting twisted tape and dimple shapes on the flow and characteristic of thermal improvement. Outcomes noticed were that the dimples and types have impact on flow and heat performance.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the flow field, thermal performance, and heat transfer augmentation in circular tube using different dimple geometrical configurations with internal twisted‐tape insert

Al‐Obaidi

2020

Heat Trans

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In this study, a numerical investigation for the fluid flow field analysis using different configuration dimple parameters in conjunction with an internal type insert in pipe is carried out. The effects of the dimple diameters with a center twisted tape on the flow pattern, pressure drop, friction factor, and heat transfer characteristics are investigated. The influence of the latter device on heat performance and thermal-hydraulic performance evaluation factor (PEF) were carried out in a pipe for fully developed flow with range for fully developed flow with range of Reynolds number (Re) of 1573 and 23 592. Experiments with numerical models are performed using different dimpled dimeters by inserting twisted tapes. The outcomes observe that the qualitative analysis for flow fields such as static pressure, dynamic pressure, velocity magnitude, wall shear stress, and turbulent kinetic energy as well as the quantities analysis for pressure drop, heat transfer coefficient friction factor, and Nu number in dimpled pipe fitted with twisted tape are greater than plain pipe. This is because using these devices cause more secondary flow, swirl flow, and flow mixing that lead to higher turbulence, which, in turn, enhance the overall heat transfer. The results indicated that the lower and higher values of thermal PEF are about 0.78 and 1.6, respectively, at the dimple dimmers of 1 mm.

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“…They showed that the PEC number ranges from 0.87 to 0.98 for Reynolds numbers varying from 5600 to 18,000. Samruaisin et al [ 32 ] embedded quadruple twisted tapes in a tube to analyze experimentally and numerically the efficacies of twisted tape arrangement and free space ratio in a turbulent regime. They reported the maximum value of 1.27 for PEC numbers in the range of studied operational conditions.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Overlapped Twisted Tapes Inserted in a Double-Pipe Heat Exchanger Using Two-Phase Nanofluid

Ghalambaz

Arasteh

Mashayekhi³

et al. 2020

Nanomaterials

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This study investigated the laminar convective heat transfer and fluid flow of Al2O3 nanofluid in a counter flow double-pipe heat exchanger equipped with overlapped twisted tape inserts in both inner and outer tubes. Two models of the same (co-swirling twisted tapes) and opposite (counter-swirling twisted tapes) angular directions for the stationary twisted tapes were considered. The computational fluid dynamic simulations were conducted through varying the design parameters, including the angular direction of twisted tape inserts, nanofluid volume concentration, and Reynolds number. It was found that inserting the overlapped twisted tapes in the heat exchanger significantly increases the thermal performance as well as the friction factor compared with the plain heat exchanger. The results indicate that models of co-swirling twisted tapes and counter-swirling twisted tapes increase the average Nusselt number by almost 35.2–66.2% and 42.1–68.7% over the Reynolds number ranging 250–1000, respectively. To assess the interplay between heat transfer enhancement and pressure loss penalty, the dimensionless number of performance evaluation criterion was calculated for all the captured configurations. Ultimately, the highest value of performance evaluation criterion is equal to 1.40 and 1.26 at inner and outer tubes at the Reynolds number of 1000 and the volume fraction of 3% in the case of counter-swirling twisted tapes model.

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Influence of regularly spaced quadruple twisted tape elements on thermal enhancement characteristics

Cited by 51 publications

References 32 publications

Numerical and Experimental Investigations of Micro Thermal Performance in a Tube with Delta Winglet Pairs

Numerical and Experimental Investigations of Micro Thermal Performance in a Tube with Delta Winglet Pairs

Analysis of the flow field, thermal performance, and heat transfer augmentation in circular tube using different dimple geometrical configurations with internal twisted‐tape insert

Investigation of Overlapped Twisted Tapes Inserted in a Double-Pipe Heat Exchanger Using Two-Phase Nanofluid

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