Experimental and numerical investigation of swirling turbulent flow and heat transfer due to insertion of twisted tapes of new models in a heated tube

Mushatet, Khudheyer S.; Rishak, Qais A.; Fagr, Mohsen H.

doi:10.1016/j.applthermaleng.2020.115070

Cited by 30 publications

(10 citation statements)

References 29 publications

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“…This publication reported that the κ − ε model was the best-simulated model and merely induced the maximum deviation of 18%. Mushatet et al (2020) introduced the RNG κ − ε turbulent model to estimate how a tapered twisted tape influenced thermo-energy transport with critical hydraulic qualities inside a heated pipe. The estimated number of the thermo-hydraulics performance factor was about 1.37 through CFD simulations.…”

Section: Introductionmentioning

confidence: 99%

Thermal-hydraulic performance of turbulent flows across a heated round tube installed through several perforated twisted tapes

Perng,

Wu,

Huang

2024

HFF

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Purpose The purpose of this study is to advance turbulent thermal convection inside the constant heat-flux round tube inserted by multiple perforated twisted tapes. Design/methodology/approach The novel design of this study is accomplished by inserting several twisted tapes and drilling some circular perforations near the tape edge (C1, C3, C5: solid tapes; C2, C4, C6: perforated tapes). The turbulence flow appearances and thermal convective features are examined for various Reynolds numbers (8,000–14,000) using the renormalization group (RNG) κ−ε turbulent model and Semi-Implicit Method for Pressure-Linked Equations (SIMPLE) algorithm. Findings The simulated outcomes reveal that inserting more perforated-twisted tapes into the heated round tube promotes turbulent thermal convection effectively. A swirling flow caused by the twisted tapes to produce the secondary flow jets between two reverse-spin tapes can combine with the main flow passing through the perforations at the outer edge to enhance the vortex flow. The primary factors are the quantity of twisted tapes and with/without perforations, as the perforation ratio remains at 2.5 in this numerical work. Weighing friction along the tube, C6 (four reverse-spin perforated-twisted tapes) brings the uppermost thermal-hydraulic performance of 1.23 under Re = 8,000. Research limitations/implications The constant thermo-hydraulic attributes of liquid water and the steady Newtonian fluid are research limitations for this simulated work. Practical implications The simulated outcomes will avail the inner-pipe design of a heat exchanger inserted by multiple perforated twisted tapes to enhance superior heat transfer. Originality/value These twisted tapes form tiny circular perforations along the tape edge to introduce the fluid flow through these bores and combine with the secondary flow induced between two reverse-spin tapes. This scheme enhances the swirling flow, turbulence intensity and fluid mixing to advance thermal convection since larger perforations cannot produce large jet velocity or the position of perforations is too far from the tape edge to generate a separated flow. Consequently, this work contributes a valuable cooling mechanism toward thermal engineering.

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Section: Introductionmentioning

confidence: 99%

Thermal-hydraulic performance of turbulent flows across a heated round tube installed through several perforated twisted tapes

Perng,

Wu,

Huang

2024

HFF

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“…In their work, Mushatet et al [3] scrutinized several configurations of tapered twisted tape housed within a heated tube both experimentally and numerically for augmented thermal and hydrodynamic performance. Investigations were conducted within turbulent Reynolds numbers ranging from 10,000 to 400,000, with the peak thermal efficiency gain recorded at 137%.…”

Section: Introductionmentioning

confidence: 99%

CFD Analysis for a Twisted Elliptical Double Tube Heat Exchangers Integrated with a Twisted Tape

Khaled,

Mushatet

2023

IJHT

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A numerical investigation into the thermal-hydraulic performance of double elliptical twisted tubes fitted with twisted tape has been conducted. The fluid flow and heat transfer in the twisted double elliptical tubes heat exchanger were modeled utilizing Navier-Stokes, energy, and turbulence equations. The governing equations were resolved using ANSYS Fluent 23.1. Twisting ratios of 5 for twisted tubes and 4 for twisted tape were applied. The Reynolds number was varied within the range of 5000 to 25000. A counter-flow arrangement was established by inputting hot water into the inner tube and cold water into the outer tube. The introduction of twisted tape (TT) resulted in enhanced fluid and centrifugal force mixing near the wall, thereby significantly influencing heat transfer in this region. The study revealed that the heat transfer and performance were notably improved in comparison to a plain double-tube heat exchanger. Furthermore, the heat exchanger's effectiveness was found to increase by 75% at a Reynolds number of 5000.

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“…The RNG k–ε turbulence model was used and the predicted values of Nusselt number, friction factor and thermal performance factor are respectively within ± 5%, ± 7% and ± 3% of the experimental data. Fagr et al 13 and Mushatet et al 14 studied the insertion of decreased tapered twisted tape and increased tapered twisted tape inside a circular tube, respectively. Both experimental and numerical study were conducted and the RNG k–ε model was chosen as turbulence model.…”

Section: Introductionmentioning

confidence: 99%

The effect of off-center placement of twisted tape on flow and heat transfer characteristics in a circular tube

Wang

2021

Sci Rep

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This study is conducted to investigate the effect of off-center placement of twisted tape on flow distribution and heat transfer in a circular tube. The effect of tape width of 20, 18, 16, 14 and 12 mm on the heat transfer performance is discussed under the same twist ratio of 2.0. The numerical analysis of the flow field, average Nusselt number, friction factor and thermo-hydraulic performance parameter of the tube are discussed with Reynolds number ranged from 2600 to 8760. The results indicate that the Nusselt number of the tube fitted with center-placed twisted tapes at various width is 7–51% higher than the plain tube, and performance in low Reynolds region was found more effective than that in high Reynolds region. The heat transfer for circular tube with twisted tape attached to the wall shows better performance than that for the tube with center-placed twisted tape. With a smaller tape width, a higher increasing ratio of Nu-wall/Nu-center is obtained. The increasing ratio for Nusselt number ranged from 3 to 18%. However, the use of twisted tape inserts is not beneficial for energy saving. The thermo-hydraulic performance parameters for convective heat transfer of helium gas flowing in a circular tube are below unity for the calculated Reynolds region.

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Experimental and numerical investigation of swirling turbulent flow and heat transfer due to insertion of twisted tapes of new models in a heated tube

Cited by 30 publications

References 29 publications

Thermal-hydraulic performance of turbulent flows across a heated round tube installed through several perforated twisted tapes

Thermal-hydraulic performance of turbulent flows across a heated round tube installed through several perforated twisted tapes

CFD Analysis for a Twisted Elliptical Double Tube Heat Exchangers Integrated with a Twisted Tape

The effect of off-center placement of twisted tape on flow and heat transfer characteristics in a circular tube

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