Journal ArticleDOI
On the correspondence between flow structures and convective heat transfer augmentation for multiple jet impingement
TLDR
In this article, particle image velocimetry (PIV) and liquid crystal thermography (LCT) measurements are taken at planes normal to the target wall and along the centerline of the jets, providing quantitative flow visualisation of jet and crossflow interactions.Abstract:
The correspondence between local fluid flow structures and convective heat transfer is a fundamental aspect that is not yet fully understood for multiple jet impingement. Therefore, flow field and heat transfer experiments are separately performed investigating mutual–jet interactions exposed in a self-gained crossflow. The measurements are taken in two narrow impingement channels with different cross-sectional areas and a single exit design. Hence, a gradually increased crossflow momentum is developed from the spent air of the upstream jets. Particle image velocimetry (PIV) and liquid crystal thermography (LCT) are used in order to investigate the aerothermal characteristics of the channel with high spatial resolution. The PIV measurements are taken at planes normal to the target wall and along the centreline of the jets, providing quantitative flow visualisation of jet and crossflow interactions. Spatially resolved heat transfer coefficient distributions on the target plate are evaluated with transient techniques and a multi-layer of thermochromic liquid crystals. The results are analysed aiming to provide a better understanding about the impact of near-wall flow structures on the convective heat transfer augmentation for these complex flow phenomena.read more
Citations
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Journal ArticleDOI
Multiple-jet impingement heat transfer in double-wall cooling structures with pin fins and effusion holes
Yu Rao,Yuyang Liu,Chaoyi Wan +2 more
TL;DR: In this article, the authors studied multiple-jet impingement heat transfer in double-wall cooling structures with narrow channels with pin fins and different size effusion holes on the target wall.
Journal ArticleDOI
Interaction of dual sweeping impinging jets at different Reynolds numbers
TL;DR: In this article, a pair of wall vortices develops and interacts in a trade-off manner in the middle region between the two sweeping jets, and the resulting time-averaged impingement of the dual jets are, in essence, very similar to the sweeping jet that would be produced from a single, but bigger, oscillator.
Journal ArticleDOI
Transient heat transfer characteristics of array-jet impingement on high-temperature flat plate at low jet-to-plate distances
TL;DR: In this paper, the transient heat transfer characteristics of air-array-jet impingement, for small jet-to-plate distances and a large temperature difference between the nozzle and plate, are presented.
Journal ArticleDOI
Influences of effusion hole diameter on impingement/effusion cooling performance at turbine blade leading edge
Junfei Zhou,Xinjun Wang,Jun Li +2 more
TL;DR: In this paper, the effects of the film cooling hole diameter and the location on the impingement/effusion cooling performance inside a concave target channel are numerically investigated.
Journal ArticleDOI
Effects of film cooling hole locations on flow and heat transfer characteristics of impingement/effusion cooling at turbine blade leading edge
TL;DR: In this article, the effects of the film cooling hole locations on the flow and heat transfer characteristics of the impingment/effusion cooling were investigated on a concave target channel with three inclined angle (0°, 30°, 60°).
References
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Journal ArticleDOI
On the identification of a vortex
Jinhee Jeong,Fazle Hussain +1 more
TL;DR: In this article, the authors propose a definition of vortex in an incompressible flow in terms of the eigenvalues of the symmetric tensor, which captures the pressure minimum in a plane perpendicular to the vortex axis at high Reynolds numbers, and also accurately defines vortex cores at low Reynolds numbers.
Journal ArticleDOI
The Proper Orthogonal Decomposition in the Analysis of Turbulent Flows
TL;DR: The Navier-Stokes equations are well-known to be a good model for turbulence as discussed by the authors, and the results of well over a century of increasingly sophisticated experiments are available at our disposal.
Eddies Stream, and Convergence Zones in Turbulent Flows
TL;DR: In this article, a set of objective criteria were found which describe regions in which the streamlines circulate, converge, or diverge, and form high streams of high velocity flow.
Eddies, streams, and convergence zones in turbulent flows
TL;DR: In this article, a set of objective criteria were found which describe regions in which the streamlines circulate, converge, or diverge, and form high streams of high velocity flow.
Journal ArticleDOI
On coherent-vortex identification in turbulence
Yves Dubief,Franck Delcayre +1 more
TL;DR: In this paper, it was shown that the pressure Laplacian is positive within a low-pressure tube of small cross section enclosed by convex isobaric surfaces in a uniform density flow.