Investigation of the concave curvature effect for an impinging jet flow

Aillaud, Pierre; Gicquel, Laurent; Duchaine, Florent

doi:10.1103/physrevfluids.2.114608

Cited by 9 publications

(1 citation statement)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the mechanisms responsible for these streak-like structures near the radial location of the secondary peak remained unclear. Other important aspects like the influence of subgrid-scale modeling in LES of impinging jets [48,49], flow dynamics and heat transfer characteristics in multiple impinging jets [50,51], the effect of wall curvature [52,53], impingement jet in cross-flow [54,55] or jet impingement onto a rotating disc [56] have been also investigated by means of LES and DNS. With regard to numerical studies of oblique impinging jets, it is worth mentioning that only a few LES studies [57,58] and no DNS, except the previous DNS study of isothermal flow by Ries et al [59], have been reported in the literature, even though this specific configuration features very interesting flow properties and is of practical relevance in cooling arrangements for gas turbine blades, allowing one to reduce the size of such systems [9], as well as in numerous other applications.…”

Section: Introductionmentioning

confidence: 99%

Near-Wall Thermal Processes in an Inclined Impinging Jet: Analysis of Heat Transport and Entropy Generation Mechanisms

Ries

Klingenberg

et al. 2018

Energies

View full text Add to dashboard Cite

In this work, near-wall thermal transport processes and entropy generation mechanisms in a turbulent jet impinging on a 45 ∘ -inclined heated surface are investigated using a direct numerical simulation (DNS). The objectives are to analyze the subtle mechanisms of heat transport in the vicinity of an inclined impinged wall, to determine the causes of irreversibilities that are responsible for the reduction of performance of impingement cooling applications and to provide a comprehensive dataset for model development and validation. Results for near-wall thermal characteristics including heat fluxes are analyzed. An entropy production map is provided from the second law analysis. The following main outcomes can be drawn from this study: (1) the location of peak heat transfer occurs not directly at the stagnation point; instead, it is slightly shifted towards the compression side of the jet, while at this region, the heat is transported counter to the temperature gradient; (2) turbulent thermal and fluid flow transport processes around the stagnation point are considerably different from those found in other near-wall-dominated flows and are strongly non-equilibrium in nature; (3) heat fluxes appear highly anisotropic especially in the vicinity of the impinged wall; (4) in particular, the heated wall acts as a strong source of irreversibility for both entropy production related to viscous dissipation and to heat conduction. All these findings imply that a careful design of the impinged plate is particularly important in order to use energy in such a thermal arrangement effectively. Finally, this study confirms that the estimation of the turbulent part of the entropy production based on turbulence dissipation rates in non-reacting, non-isothermal fluid flows represents a reliable approximate approach within the second law analysis, likewise in the context of computationally less expensive simulation techniques like RANS and/or LES.

show abstract