Effects of dimples’ arrangement style of rough surface and jet geometry on impinging jet heat transfer

Çelik, Nevin

doi:10.1007/s00231-019-02714-x

Cited by 17 publications

(6 citation statements)

References 25 publications

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“…The validity of the experimental data in terms of Nu was tested using the Dittus-Boelter equation (Equation ( 16)) and the Gnielinski equation (Equation (17)) and for the Nu represented as for a smooth duct. Nu = 0.023Re 0.8 Pr 0.4 (16) The Gnielinski equation for the Nusselt Number for 2300 < Re < 5 × 10 6 is:…”

Section: Validity Testmentioning

confidence: 99%

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Sustainability and Cost Effectiveness Analysis of Staggered Jet Impingement on Solar Thermal Collector

Maithani

Kumar

et al. 2022

Energies

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The sustainability index, waste energy ratio and improvement potential of a staggered air jet impingement on the staggered spherical protrusions of a roughened absorber plate were derived for the present study to evaluate exergy losses and irreversibility in the system. The experimental analysis was carried out for selected parameters: relative streamwise pitch, relative spanwise pitch and relative jet diameter to hydraulic diameter ratio. The flow Reynolds number ranged from 4000–18,000. The augmentation in Nusselt number and friction factor compared to a smooth surface was 4.9 and 12.4 times, respectively. The statistical correlation developed determined the maximum thermohydraulic performance parameter and exergetic efficiency be 3.02 and 3.87%, respectively. The magnitude of the sustainability index, waste energy ratio and improvement potential was found to be 1.0347, 0.962 and 10.84, respectively, for the entire range of tested parameters. A cost analysis was also performed to evaluate the cost-effectiveness of the solar thermal system with and without turbulent promoters.

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Section: Validity Testmentioning

confidence: 99%

“…The validity of the experimental data in terms of was tested using the Dittus-Boelter equation (Equation ( 16)) and the Gnielinski equation (Equation (17)) and for the represented as for a smooth duct.…”

Section: Validity Testmentioning

confidence: 99%

Sustainability and Cost Effectiveness Analysis of Staggered Jet Impingement on Solar Thermal Collector

Maithani

Kumar

et al. 2022

Energies

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“…In past decades, Perry [9] and Martin [10] have carried out pioneering research in this field, while in recent years, Barbosa et al [11], Shukla et al [12], and Dewan et al [13] have systematically reviewed the research in this field. Several studies [14][15][16] have assessed the contribution of each variable to heat transfer through the design of experiments (DOE) [17], indicating that the Reynolds number, nozzle shape, and H/D were important factors affecting heat transfer, while S/D and target geometry had less influence. Other studies [18,19] showed that jet angle also served as a key factor affecting heat transfer.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on the Heat Transfer of Confined Air-Jet Quenching of Steel Sheets

Ye,

Fu,

Liu

et al. 2024

Metals

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The high flatness quenching of ultra-high-strength steel sheets is a technical problem in the steel industry. In this study, the traditional water and spray quenching methods were abandoned, and the roller-constrained slot air-jet quenching method was proposed for steel sheets below 3 mm thickness, which provided a theoretical reference for producing thinner, wider, and higher-flatness steel sheets. A 2D roller-constrained slot air-jet numerical model was established to study the flow field and heat transfer characteristics under the conditions of Reynolds number 24,644–41,076, a dimensionless jet height of 16–24, and a jet angle of 45°–135°. The results showed that the average Nusselt number on the heat transfer surface was proportional to Rem. At the same time, high-intensity heat transfer was achieved when the dimensionless height and jet angle were properly combined. At the same Reynolds number, the heat transfer intensity could be increased by 289%. In addition, the position of the peak Nusselt number was affected by reducing the jet angle, which served as an effective strategy for adjusting the martensite ratio and obtaining ideal mechanical properties.

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“…Most existing literature about roughened surfaces is on flat surfaces [18][19][20][21]. Likewise, structures such as ribs [22][23][24][25][26], fins [27][28][29][30][31], grooves [32][33][34][35], and dimples [36][37][38][39] can enhance the concave target surface's thermal performance. Additionally, the channel structure can be optimized for better heat transfer [40][41][42][43][44].…”

Section: Introductionmentioning

confidence: 99%

Heat and Flow Characteristics of Aerofoil-Shaped Fins on a Curved Target Surface in a Confined Channel for an Impinging Jet Array

Yalçınkaya,

Durmaz,

Tepe

et al. 2024

Energies

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The main purpose of this investigation was to explore the heat transfer and flow characteristics of aero-foil-shaped fins combined with extended jet holes, specifically focusing on their feasibility in cooling turbine blades. In this study, a comprehensive investigation was carried out by applying impinging jet array cooling (IJAC) on a semi-circular curved surface, which was roughened using aerofoil-shaped fins. Numerical computations were conducted under three different Reynolds numbers (Re) ranging from 5000 to 25,000, while nozzle-to-target surface spacings (S/d) ranged from 0.5 to 8.0. Furthermore, an assessment was made of the impact of different fin arrangements, single-row (L1), double-row (L2), and triple-row (L3), on convective heat transfer. Detailed examinations were performed on area-averaged and local Nusselt (Nu) numbers, flow properties, and the thermal performance criterion (TPC) on finned and smooth target surfaces. The study’s results revealed that the use of aerofoil-shaped fins and the reduction in S/d, along with surface roughening, led to significant increases in the local and area-averaged Nu numbers compared to the conventional IJAC scheme. The most notable heat transfer enhancement was observed at S/d = 0.5 utilizing extended jets and the surface design incorporating aerofoil-shaped fins. Under these specific conditions, the maximum heat transfer enhancement reached 52.81%. Moreover, the investigation also demonstrated that the highest TPC on the finned surface was achieved when S/d = 2.0 for L2 at Re = 25,000, resulting in a TPC value of 1.12. Furthermore, reducing S/d and mounting aerofoil-shaped fins on the surface yielded a more uniform heat transfer distribution on the relevant surface than IJAC with a smooth surface, ensuring a relatively more uniform heat transfer distribution to minimize the risk of localized overheating.

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Effects of dimples’ arrangement style of rough surface and jet geometry on impinging jet heat transfer

Cited by 17 publications

References 25 publications

Sustainability and Cost Effectiveness Analysis of Staggered Jet Impingement on Solar Thermal Collector

Sustainability and Cost Effectiveness Analysis of Staggered Jet Impingement on Solar Thermal Collector

Numerical Study on the Heat Transfer of Confined Air-Jet Quenching of Steel Sheets

Heat and Flow Characteristics of Aerofoil-Shaped Fins on a Curved Target Surface in a Confined Channel for an Impinging Jet Array

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