Heat transfer and flow structure in a rotating duct with detached pin fins

Du, Wei; Luo, Lei; Wang, Songtao; Liu, Jian; Sundén, Bengt

doi:10.1080/10407782.2019.1580957

Cited by 19 publications

(5 citation statements)

References 32 publications

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“…Based on the above discussion, realizable k-ε turbulent model shows the best agreement with experimental results under both stationary and rotating conditions. In addition, previous studies (Du et al , 2019; Luo et al , 2018; Yan et al , 2021) also acknowledged that realizable k-ε turbulent model shows the better ability of accurately capturing and evaluating the heat transfer enhancement and friction loss of pin fin-dimpled channels. Thus, realizable k-ε turbulent model combined with enhanced wall function is chosen.…”

Section: Computational Methods and Proceduresmentioning

confidence: 96%

“…As shown in Figure 2, the endwalls, dimples and pin fins are applied with q = 1,000 W/m 2 wall heat flux (Du et al , 2019; Luo et al , 2018). All the walls are viewed as no-slip wall.…”

Section: Computational Methods and Proceduresmentioning

confidence: 99%

“…Park et al (2008, 2011) studied the impact of pin fin height and inclination on heat transfer under rotating condition through experimental methods. Du et al (2019) numerically studied detached pin fins and concluded that the leaked secondary flow affected heat transfer greatly.…”

Section: Introductionmentioning

confidence: 99%

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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

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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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Section: Computational Methods and Proceduresmentioning

confidence: 96%

“…As shown in Figure 2, the endwalls, dimples and pin fins are applied with q = 1,000 W/m 2 wall heat flux (Du et al , 2019; Luo et al , 2018). All the walls are viewed as no-slip wall.…”

Section: Computational Methods and Proceduresmentioning

confidence: 99%

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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

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“…In practice, rotating thermal flux frequently occurs in a variety of rotational setups. A wide range of studies [4][5][6][7][8] has been conducted to analyze the flow and heat transfer for the rotational/non-rotating domain.…”

Section: Nomenclaturementioning

confidence: 99%

Impacts of Rotation on Unsteady Fluid Flow and Energy Distribution through a Bending Duct with Rectangular Cross Section

Islam¹,

Mondal²,

Saha³

2022

Energy Engineering

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A depth understanding of fluid flow past a curved duct having rectangular cross-section with different aspect ratios (l) are essential for various engineering applications such as in chemical, mechanical, biomechanical and bio-medical engineering. So highly ambitious researchers have given significant attention to study new characteristics of fluid flow in a curved duct. The flow characterization in the rectangular duct has been studied over a wide range of numerical and selective experimental studies. However, proper knowledge with the effects of Coriolis force for different aspect ratios is important for better understanding of the transitional behaviour and the subsequent heat generation, which is required to improve further. The purpose of this study is to reveal insight into the transitional flow pattern and heat transfer in a curved rectangular domain. The Navier-Stokes equations are solved using the spectral method, while the Crank-Nicolson method is used to solve the energy equation. An in-house FORTRAN code is developed to get the numerical solution. For post-processing purposes, Tecplot-360 and Ghost-script tools are used. The present study exposes development of Dean vortices that affect heat generation as well as thermal enhancement in the flow with underlying the flow controlling parameters, the Dean number (Dn), the Grashof number (Gr) and the Taylor number (Tr). Time-dependent results followed by phase spaces show that transient flow undergoes in the scenario 'chaotic → multi-periodic→ periodic → steady-state' generating 2-to 8-vortices for the periodic/multi-periodic flow at 2000 ≤ Tr ≤ 2205 for l = 2, whereas similar sort of flow is observed in the range of 3100 ≤ Tr ≤ 3195 for l = 3. More complicated 4-to 13-vortex solutions are obtained for the chaotic flow regime at l = 2 in the range of 0 ≤ Tr < 2200 and at l = 3 in the range of 0 ≤ Tr < 3100. The chaotic flow that occurs at the certain range of Tr proficiently intensifies the heat transfer than the unperturbed, periodic or multi-periodic flow. The overall investigation reveals that in the rotating duct, the temperature-influenced buoyancy compulsion and centrifugal-coriolis joint forces are dominant, influencing the characteristic of the fluid and thus optimizing the transfer of heat. The present investigation will contribute to enhancing the understanding of fluid flow and heat transfer of internal heating/cooling/gas turbines, electric generators, biological systems, and some separation processes.

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“…However, the friction factor is also increased after adoption of other cooling structures. For a rotating pin fin duct, the Coriolis force augments the HTC on the pressure side (trailing side) and suppresses the HTC on the suction side (leading side) (Du et al , 2019b). In addition, the Coriolis force induces a secondary flow near the wake region.…”

Section: Introductionmentioning

confidence: 99%

Enhanced heat transfer in a labyrinth channels with ribs of different shape

Wang

et al. 2019

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Purpose The purpose of this study is to enhance the thermal performance in the labyrinth channel by different ribs shape. The labyrinth channel is a relatively new cooling structure to decrease the temperature near the trailing region of gas turbine. Design/methodology/approach Based on the geometric similarity, a simplified geometric model is used. The k − ω turbulence model is used to close the Navier–Stokes equations. Five rib shapes (one rectangular rib, two arched ribs and two trapezoid ribs) and five Reynolds numbers (10,000 to 50,000) are considered. The Nusselt number, flow structure and friction factor are analyzed. Findings Nusselt number is tightly related to the rib shape in the labyrinth channel. The different shapes of the ribs result in different horseshoe vortex and wake region. In general, the arched rib brings the highest Nusselt number and friction factor. The Nusselt number is increased by 15.8 per cent compared to that of trapezoidal ribs. High Nusselt number is accompanied by the high friction factor in a labyrinth channels. The friction factor is increased by 64.6 per cent compared to rectangular ribs. However, the rib shape has a minor effect on the overall thermal performance. Practical implications This study is useful to protect the trailing region of advanced gas turbine. Originality/value This paper presents the flow structure and heat transfer characteristics in a labyrinth channel with different rib shapes.

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Heat transfer and flow structure in a rotating duct with detached pin fins

Cited by 19 publications

References 32 publications

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

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

Impacts of Rotation on Unsteady Fluid Flow and Energy Distribution through a Bending Duct with Rectangular Cross Section

Enhanced heat transfer in a labyrinth channels with ribs of different shape

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