Local heat transfer distribution on a smooth flat plate impinged by a slot jet

Nirmalkumar, M.; Katti, Vadiraj; Prabhu, S.V.

doi:10.1016/j.ijheatmasstransfer.2010.09.030

Cited by 55 publications

(19 citation statements)

References 16 publications

(19 reference statements)

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“…Heat transfer rates in the case of impinging jets are affected by various parameters like the Reynolds number, jet to plate spacing, radial distance from a stagnation point, target plate inclination, nozzle geometry, roughness of the target plate and turbulence intensity at the nozzle exit. The majority of studies are experimental ones (Goordo et al, 2007;Nirmalkumar et al, 2011). However, many simulations of impingement cooling systems are numerical (Ee-Mahghany et al, 2012; Żukowski, 2013).…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of local heat transfer distribution on surfaces with a non-uniform temperature under an array of impinging jets with various nozzle shapes

Marzec

Kucaba-Pietal

2017

jtam

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Numerical calculations of heat transfer characteristics of an impingement cooling system with a non-uniform temperature on a cooled surface using ANSYS CFX have been performed. The influence of a surface heat flux q w (x) and a nozzle shape on the Nusselt number distribution on the cooled surface has been studied. The setup consisted of a cylindrical plenum with an inline array of ten impingement jets. Cylindrical, convergent divergent shapes of nozzles and linear temperature distribution on the cooled surface have been considered for various heat fluxes q w (x). Results indicate that geometry of the cylindrical nozzles resulted in the highest Nusselt numbers along the cooled surface. The line of the averaged Nusselt number has a trend to increase in the direction of the flow for the cooling system with increasing values of the surface heat flux q(x). This tendency can be observed for all presented shapes of jets. On the other hand, for decreasing functions of the heat flux q w (x), the Nusselt number distribution is more uniform. It can be observed for all types of nozzles. Very similar values of the Nusselt number occur especially for the non-uniform heat flux 5000-2500 W/m 2 . For constant values of the heat flux q(x) = 5000 W/m 2 , the line of the average Nusselt number has a trend to increase slightly in the direction of the flow. Numerical analysis of different mesh density results in good convergence of the GCI index, what excludes mesh size dependency. The presented study is an extension of the paper (Marzec and Kucaba-Piętal, 2016) and aims at answering the question how the Nusselt number distribution on the cooled surface is affected by various geometries of nozzles for a non-uniform surface heat flux q w (x).

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Section: Introductionmentioning

confidence: 99%

Numerical investigation of local heat transfer distribution on surfaces with a non-uniform temperature under an array of impinging jets with various nozzle shapes

Marzec

Kucaba-Pietal

2017

jtam

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“…The impingement cooling found its use in early 1960's, especially in the high heat flux region such as in the gas turbine blade [1]. It received considerable attention due to its inherent characteristics of high heat transfer rate.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Heat Transfer Due to Twinjets Impingement onto an Isothermal Moving Plate

Başaran

Selimefendigil

2013

MCA

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Abstract-In this study, heat transfer from a moving isothermal hot plate due to double impinging vertical slot jets was investigated for a laminar flow. The rectangular geometry consists of a confining adiabatic wall placed parallel to the moving impingement. The jets are located symmetrically at mid point of upper wall. Water and Al 2 O 3 nanoparticles mixture with different volumetric fraction was used as working medium. In considered jet impingement problem, the effects of the jet exit Reynolds numbers, ranging from 50 to 200, the normalized plate velocity, ranging from 0 to 2, and volumetric fractions of nanofluid, ranging from 0% to 6% were investigated. The commercial software package based on finite volume method FLUENT (version 6.3.26) is used in this study for the computations. It has been observed that increasing normalized plate velocity increases the heat transfer from bottom surface. Similarly, increasing Reynolds number of slot jets leads to enhancement of heat transfer. Besides, increasing volumetric fraction of nanofluid conributes to heat transfer enhancement.

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“…A multitude of previous studies have documented that the overall and local impinging jet heat transfer characteristics on a flat plate (as the most simplistic configuration in all impinging jet configurations) depend strongly on the jet-to-flat plate distance, H, among other parameters [5][6][7][8][9][10][11][12][13][14][15][16]. Depending on the longitudinal position relative to the length of potential core of the jet, either two peaks of local heat transfer (a primary peak at the stagnation point and a second peak off from the stagnation point) or a single peak (only at the stagnation point) exist on a flat plate.…”

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confidence: 99%

“…Local heat transfer, especially at the stagnation point where the highest heat transfer and pressures exist on a target surface (e.g., flat plate) due to stagnation, substantially varies with the jet-to-flat plate distance H. It has been observed that the highest heat transfer at the stagnation point occurs at very small jet-to-flat plate distances due to the local acceleration of the fluid between the jet nozzle and the flat plate and a significant increase in local turbulence level [12][13][14]17]. As the jet-to-flat plate distance is further increased, heat transfer at the stagnation point nonmonotonically varies [12][13][14]18,19] experiencing 1) a gradual decrease, 2) to a local minimum, 3) a gradual increase, 4) to a local maximum (peak), and 5) a monotonic decrease.…”

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confidence: 99%

Stagnation Heat Transfer on a Concave Surface Cooled by Unconfined Slot Jet

Nguepnang

Boer

Kim

2016

Journal of Thermophysics and Heat Transfer

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Heat transfer at the stagnation point on a concave surface and on a flat plate subjected to unconfined slot jet impingement is characterized and compared at a fixed jet Reynolds number of Re B 20;000. The concave surface diameter-to-slot width ratio is fixed at 9.0, whereas the slot exit-to-target surface distance, H∕B, varies from 0.5 to 20.0. In particular, the nonmonotonic variation of heat transfer at the stagnation point with H∕B is fluidically explained. The present results clarify that the deflection zone formed on the target surface as a result of the jet impingement leads to the upstream shift of the peak in turbulence strength that exactly coincides with the peak of heat transfer at the stagnation point. With the concave surface, the impinging jet deflected radially on the surface is reentrained into the incoming jet due to the curvature, which causes the shortening of the potential core of the slot jet and the longitudinal upstream shift of the peak in turbulence strength compared with the flat plate. Therefore, the peak in heat transfer at the stagnation point occurs at shorter H∕B on the concave surface than on the flat plate.

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Local heat transfer distribution on a smooth flat plate impinged by a slot jet

Cited by 55 publications

References 16 publications

Numerical investigation of local heat transfer distribution on surfaces with a non-uniform temperature under an array of impinging jets with various nozzle shapes

Numerical investigation of local heat transfer distribution on surfaces with a non-uniform temperature under an array of impinging jets with various nozzle shapes

Numerical Study of Heat Transfer Due to Twinjets Impingement onto an Isothermal Moving Plate

Stagnation Heat Transfer on a Concave Surface Cooled by Unconfined Slot Jet

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