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

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 ReB=20,000. The concave surface diameter-to-slot width ratio is fixed at 9.0, whereas the slot exit-to-target su...

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Bibliographic Details
Published in:Journal of thermophysics and heat transfer 2016-07, Vol.30 (3), p.558-566
Main Authors: Nguepnang, Maurel A, Boer, Michael, Kim, Tongbeum
Format: Article
Language:English
Subjects:
Deflection
Deodorants
Flat plates
Fluid dynamics
Fluid flow
Heat transfer
Jet impingement
Reynolds number
Stagnation point
Turbulence
Upstream
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Summary: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 ReB=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 re-entrained 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.
ISSN:0887-8722
1533-6808
DOI:10.2514/1.T4793