Turbulent swirling impinging jet arrays: A numerical study on fluid flow and heat transfer

Debnath, Sudipta; Khan, Md. Habib U.; Ahmed, Zahir U.

doi:10.1016/j.tsep.2020.100580

Cited by 25 publications

(15 citation statements)

References 41 publications

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“…The results for Nu, summarized in Table 4, show that the numerical predictions present a maximum deviation of 12% when compared with the correlations, which seems to be reasonable, according to other studies [44,54,62,63]. When compared with the experimental data, this difference is approximately equal to 5%, which is an acceptable difference, explained by external factors that are not accounted for numerically.…”

Section: Numerical Model Validationsupporting

confidence: 77%

“…Several authors agree that the RANS type SST k-ω model is both accurate and computing time-saving for the modeling of multiple jet impingement systems [42][43][44][45][46]. In that sense, this turbulence model was implemented in this work.…”

Section: Turbulence Modellingmentioning

confidence: 84%

“…This low-Re approach is relevant for flows that lie in the transition regime or flows with low turbulence, such as the flow applied in this study. However, the SST k-ω model presents accurate results for highly turbulent flow (Re > 10,000), as presented by [11,44,46]. Equations ( 15) and ( 16) express the turbulence kinetic energy, k, and the specific dissipation rate, ω, respectively.…”

Section: Turbulence Modellingmentioning

confidence: 99%

“…The complexity of the flow was expected to increase with the non-flat plate. However, since a near wall grid quality was ensured (y + < 2)-and considering that the number of elements applied in previous studies, which modeled roughened surfaces with the SST k-ω [10,44,46], was close to the one applied in this study-the mesh used for the flat plate case was also implemented for the non-flat plate.…”

Section: Grid Independencymentioning

confidence: 99%

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Experimental and Numerical Study of Multiple Jets Impinging a Step Surface

Barbosa

Teixeira

2021

Energies

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Multiple jet impingement is a widely implemented convective process for enhancing heat transfer over target surfaces. Depending on the engineering application, the impinging plate can have different configurations. However, the increased complexity of the surface induces complicated thermal behaviors that must be analyzed. In that sense, this study consisted of the experimental and numerical analysis of multiple jets impinging on a step surface. A particle image velocimetry technique was applied to measure velocity fields, while a heat flux sensor was mounted on the surface to determine the heat transfer. Numerical simulations, for both flat and non-flat plates, were conducted in ANSYS FLUENT applying the SST k-ω model, and experimental results were used to validate the model. Three surface configurations were analyzed, flat, 1 D, and 2 D steps, and the results show an increase in the average Nusselt number compared with the flat plate, 9% and 20%, respectively. This increase was mainly due to the intensification of the flow turbulence induced by the step. Numerical results were in good agreement with the experiments, but the heat transfer was slightly underpredicted for the 2 D step case due to the difficulty of predicting with accuracy the velocity field near the step.

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Section: Numerical Model Validationsupporting

confidence: 77%

Section: Turbulence Modellingmentioning

confidence: 84%

Section: Turbulence Modellingmentioning

confidence: 99%

Section: Grid Independencymentioning

confidence: 99%

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Experimental and Numerical Study of Multiple Jets Impinging a Step Surface

Barbosa

Teixeira

2021

Energies

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“…It was observed from the results that at H/D = 2, the weakly swirling jet inflow condition suppresses heat transfer. A numerical investigation was performed by Debnath et al [93] to study the comparison of the effect of swirling and non-swirling jet array impingement flow on heat transfer performance. The two conditions were swirling flow (S = 0.74) and non-swirling flow (S = 0), the jet-plate spacing (H/D) was kept constant at 2.0, and the Reynolds number used was 11,600.…”

Section: Excited Jetsmentioning

confidence: 99%

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

et al. 2021

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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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Thermal characteristics of arrays of swirling impinging jets: Effect of Reynolds number, impingement distance, and jet‐to‐jet separation

et al. 2022

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This paper numerically investigates both the inline and staggered arrays of circular multiple swirling air jets that impinge perpendicularly onto a smooth flat surface. The simulations were conducted for various flow and geometric parameters, such as Reynolds number (Re = 11,600, 24,600, and 35,000), jet‐to‐surface distance (H/D = 1, 2, 3, and 4), jet‐to‐jet separation distance (Z/D = 1.5, 3.0, and 4.5) and swirl numbers (S = 0, 0.3, and 0.75), where D is the nozzle diameter. For S = 0.75, a strong recirculation develops due to the vortex breakdown, depends on Z/D, around the axis and near the wall. The extent of the recirculation is larger for the staggered array. Intense heat transfer is anticipated at strong swirl and close impingement cases with the expense of uniformity; whereas a relatively even heat transfer is observed for larger impingements. The increase in jet‐to‐jet separation enhances the overall cooling effect and the staggered configuration of nozzles gives better performance. It appears that both the crossflow and turbulence around the periphery of each jet predominantly govern the heat transfer characteristics. The enhancement of heat transfer occurs for increasing Re, and the overall Nusselt number (Nu) prediction is scaled by Ren, with n dependent on S. Finally a correlation is developed for the average Nusselt number to relate different control parameters.

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Turbulent swirling impinging jet arrays: A numerical study on fluid flow and heat transfer

Cited by 25 publications

References 41 publications

Experimental and Numerical Study of Multiple Jets Impinging a Step Surface

Experimental and Numerical Study of Multiple Jets Impinging a Step Surface

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

Thermal characteristics of arrays of swirling impinging jets: Effect of Reynolds number, impingement distance, and jet‐to‐jet separation

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