Effect of dimple pitch and depth on jet impingement heat transfer over dimpled surface impinged by multiple jets

Jet impingement is considered to be an effective technique to enhance the heat transfer rate, and it finds many applications in the scientific and industrial horizons. The objective of this paper is to summarize heat transfer enhancement through different jet impingement methods and provide a platform for identifying the scope for future work. This study reviews various experimental and numerical studies of jet impingement methods for thermal-hydraulic improvement of heat transfer surfaces. The jet impingement methods considered in the present work include shapes of the target surface, the jet/nozzle–target surface distance, extended jet holes, nanofluids, and the use of phase change materials (PCMs). The present work also includes both single-jet and multiple-jet impingement studies for different industrial applications.

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“…Adopted from [51]. A direct relation of Nu with the Reynolds number for both hole shapes was reported.…”

Section: Vinze Et Al [51] Dimplementioning

confidence: 99%

Heat Transfer Augmentation through Different Jet Impingement Techniques: A State-of-the-Art Review

et al. 2021

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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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“…The cooling air pumped into the turbine blade internal passage is used to carry off the heat from the hot wall. Many turbulence promoters, rib (Li et al , 2015; Raisee and Rokhzadi, 2009; Singh et al , 2017; Xie et al , 2015), pin fin (Du et al , 2021; Luo et al , 2020; Ye et al , 2019), dimple (Fazli and Raisee, 2019; Rao et al , 2015; Vinze et al , 2019), etc., are arranged on the internal passage wall so as to low the thermal load by promoting the convective heat transfer between the hot wall and cooling air. The turbine blade trailing edge is always arranged with pin-fin arrays to enhance heat transfer.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of heat transfer characteristics in a pin fin-dimpled channel with different pin fins and dimple locations

Yan

Luo

Zhang

et al. 2022

HFF

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Purpose This paper aims to investigate the influences of dimple location on the heat transfer performance of a pin fin-dimpled channel with upright/curved/inclined pin fins under stationary and rotating conditions. Design/methodology/approach Numerical methods based on a realizable k-ε turbulent model are used to conduct this study. Three kinds of pin fins (upright, curved, inclined) and three dimple locations (front, middle, behind) are studied for Ro varying from 0 to 0.5. Findings On the whole, pin fin plays a dominated role in heat transfer performance compared to dimple. The heading path and interaction of the longitudinal secondary flow and jet-like flow critically affect heat transfer performance. The formation, development and impingement of jet-like flow and longitudinal secondary flow are significantly affected by dimple locations. Dimple at behind position shows the poorest heat transfer enhancement. Originality/value This study is an extend of another previous study in which an innovative curved pin fin is proposed. The originality of this paper is to evaluate the heat transfer performance for the combined cooling structure of dimple and pin fin, which will provide original and useful application and experience for turbine blade design.

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Effect of dimple pitch and depth on jet impingement heat transfer over dimpled surface impinged by multiple jets

Cited by 35 publications

References 17 publications

Heat Transfer Augmentation through Different Jet Impingement Techniques: A State-of-the-Art Review

Heat Transfer Augmentation through Different Jet Impingement Techniques: A State-of-the-Art Review

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

Numerical analysis of heat transfer characteristics in a pin fin-dimpled channel with different pin fins and dimple locations

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