Thermo-hydraulic performance of tube with decaying swirl flow generators

Bilen, Kadir; Tokgöz, Nehir; Solmaz, İsmail; Balta, Tuba

doi:10.1016/j.applthermaleng.2021.117643

Cited by 11 publications

(5 citation statements)

References 42 publications

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“…The authors elaborated that this was due to the length of the test section determining the overall possible heat transfer improvement, with longer test sections yielding worse results due to the swirl's decay. Bilen et al [10] studied the swirl-inducing inlet where the swirl generator was long enough to ensure a good swirl was generated with minimum fluid disturbance due to the sudden redirection. The authors found that higher angle swirl generators produced better heat transfer performance across the outer walls of the test section.…”

Section: Introductionmentioning

confidence: 99%

Investigation of heat transfer performance within annular geometries with swirl-inducing fins using clove-treated graphene nanoplatelet colloidal suspension

Nair

Oon

Tan

et al. 2022

J Therm Anal Calorim

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The paper investigated the benefits of having fins that induce swirling flow within an annular passage. The importance of the vortical structures produced using different fin angles and flow velocities in heat transfer was studied. The combination of swirling fluid with recirculation on heat transfer within an annular domain was not fully understood, and this paper aims to address that gap. The 10°, 20°, 30° and 40° angled fins were investigated to understand the changes in heat transfer performance as fluid recirculation becomes more dominant as angles become steeper. The usage of CGNP colloidal suspension was investigated for its potential benefits in heat transfer in a domain with angled fins. The CGNP concentrations of 0.025, 0.075 and 0.1 mass % were used as part of this investigation. Higher concentrations of CGNP increased the overall heat transfer coefficient. A more compact fin spacing improved heat transfer performance at the expense of increased pressure drop. Fin angles of 20° and 30° yielded poor heat transfer performance in the transitional flow regime (2000 < Re < 3000) due to the smaller swirling longitudinal vortices being insufficient in promoting fluid mixing from the thermal boundary layer into the freestream.

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Section: Introductionmentioning

confidence: 99%

Investigation of heat transfer performance within annular geometries with swirl-inducing fins using clove-treated graphene nanoplatelet colloidal suspension

Nair

Oon

Tan

et al. 2022

J Therm Anal Calorim

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“…The formulation magnitude of the strain rate represented by the symbol S abs is expressed in Equation (7). The equations of the α* and F 2 in Equation ( 6) are formulated in Equations ( 8) and (9), respectively.…”

Section: Methodsmentioning

confidence: 99%

“…The use of the swirler is to create a spiral motion of the flow and provide a sufficient centrifugal force for the fluid to prolong the fluid residence times, increase the swirl intensity, enhance the mixing/separation ratio, improve the heat transfer performance, augment friction factor, and minimize the pressure drop. [6][7][8] Nevertheless, the unreasonable design of the swirler would also eliminate the advantages of the swirling flow. The design and optimization of swirler in the industrial practice should carry forward to form a reasonable swirl flow pattern and minimize its disadvantages according to the requirements of specific industrial processes.…”

Section: Introductionmentioning

confidence: 99%

Insights into the hydrodynamics in the annular pipe of industrial‐scale top‐blown smelting furnace

Wan,

Yang,

Tang

et al. 2024

Can J Chem Eng

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The coaxial jet consisting of swirl jet and axial jet plays a critical role in the industrial processes but is rarely investigated; therefore, it is numerically explored by means of the computational fluid dynamics (CFD) approach in the present work. The force on the swirler, axial and tangential velocity at the annular pipe outlet, and the spatial distribution of swirl number (SN) are selected to evaluate the effect of geometrical parameters on the swirling performance. The results clarify that the velocity and their azimuthal components in the transverse cross‐section can be categorized into six segments based on high/low velocity values. The coaxial jets form a weak swirl with high axial, certain tangential, and low radial velocities. x‐ and y‐vorticity vary within −200 to 200 s−1. Coaxial jet mixing decays the SN. Based on the multi‐objective matrix analysis, swirler height has the largest effect on swirl performance followed by diameter, angle, and number based on analysis. Optimal parameters are 130° vane angle, 240 mm diameter, 10 vanes, and 250 mm height of the swirler.

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“…Besides the Gnielinski correlation equation for annular tubes, the Petukhov correlation for circular tubes, shown in Equation (23), was also used [37]. This correlation equation used the friction factor equation from Equation (24), which applies to a wide Re range [38].…”

Section: Theoretical Validationmentioning

confidence: 99%

“…Identifying the optimal swirl angle can ensure that the pressure drop incurred from the addition of swirl inducing feature is essential in obtaining the best possible ratio in heat transfer improvement versus the increase in pressure drop. The optimal swirl angle was stated to be in the range of 45 °to 50 ° [23,24]. However, higher angles were not explored as the studies used the mentioned angles as their highest evaluated angle.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Angled Fins in Generating Swirling Flows with Vortices That Augment Heat Transfer Performance in an Annular Conduit

Nair,

Tan,

Wang

et al. 2023

International Journal of Energy Research

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This paper examined the usage of thermally conductive angled fins within an annular conduit through numerical simulation. Despite the thermally conductive nature of the fins increasing heat transfer surface area, this investigation found that using an optimal fin angle can promote the generation of vortical structures which aid heat transfer. Using ANSYS-Fluent with the SIMPLEC algorithm and the SST κ − ω turbulence model, this research found that heat transfer performance improved considerably when the generated vortices were sufficiently large and robust. However, the type of generated vortex had a profound impact when optimising for higher performance evaluation criterion (PEC) values. Longitudinal vortices improved heat transfer performance with a low impact on pressure drop increase, unlike transverse vortices, which increased pressure drop significantly. The fin angles of 50° and 60° yielded high heat transfer performance without much increase in pressure drop, thus resulting in higher PEC values. Additionally, using fin heights that correlate to 20% to 60% of the gap between the concentric walls was ideal when designing heat exchangers to achieve higher PEC values. The results of this numerical investigation have been validated both theoretically and experimentally to ensure accurate reporting of the findings.

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Thermo-hydraulic performance of tube with decaying swirl flow generators

Cited by 11 publications

References 42 publications

Investigation of heat transfer performance within annular geometries with swirl-inducing fins using clove-treated graphene nanoplatelet colloidal suspension

Investigation of heat transfer performance within annular geometries with swirl-inducing fins using clove-treated graphene nanoplatelet colloidal suspension

Insights into the hydrodynamics in the annular pipe of industrial‐scale top‐blown smelting furnace

The Effect of Angled Fins in Generating Swirling Flows with Vortices That Augment Heat Transfer Performance in an Annular Conduit

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