Turbulent Boundary Layer Heat Transfer on Curved Surfaces

Mayle, R. E.; Blair, M. F.; Kopper, F. C.

doi:10.1115/1.3451021

Cited by 52 publications

(17 citation statements)

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“…The Nusselt number increases with increasing surface curvature at the stagnation point. This phenomenon is due to the Taylor-G rtler vortices, which can significantly increase the momentum and energy exchange near the wall, and enhance the heat transfer for flow over a concave surface, as supported by Mayle et al [33] and Thomann [34]. The jet surface curvature at the stagnation point with = 30° is a little lower than that with = -45°, but the jet impingement angle with = 30° is much larger, resulting in a larger Nusselt number at the stagnation point with = 30°.…”

Section: Influence Of Circumferential Angle Of Jet Holes On the Piccomentioning

confidence: 80%

Experimental study of jet impingement heat transfer on a variable-curvature concave surface in a wing leading edge

Peng

Lin

et al. 2015

International Journal of Heat and Mass Transfer

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Abstract:In this paper, extensive experimental investigation of the heat transfer characteristics of jet impingement on a variable-curvature concave surface in a wing leading edge was conducted for aircraft anti-icing applications. The experiments were carried out over a wide range of parameters: the jet Reynolds number, Rej, from 51021 to 85340, the relative tube-to-surface distance, H/d, from 1.736 to 19.76, and the circumferential angle of jet holes on the piccolo tube, , from -60° to 60°. In addition, jet impingements with single one, two and three rows of aligned jet holes were all investigated. Experimental results revealed the effects of various parameters on the performance and characteristics of jet impingement heat transfer in the specific structure adopted here, and our insufficient understanding on the corresponding physical mechanism was presented. It was found that the jet impingement heat transfer performance was enhanced with the increase of jet Reynolds number.For single one row of jet holes, an optimal H/d of 4.5 was determined under Rej = 51021 and d = 2mm, for which the jet impingement achieved the best heat transfer performance. For two and three rows of aligned jet holes, the Nux curves in the chordwise direction exhibited much different shapes due to different intensity of the interference between adjacent air jets. This work contributes to a better understanding of the jet impingement heat transfer on a concave surface in a wing leading edge, which can lead to optimal design of the aircraft anti-icing system.

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Section: Influence Of Circumferential Angle Of Jet Holes On the Piccomentioning

confidence: 80%

Experimental study of jet impingement heat transfer on a variable-curvature concave surface in a wing leading edge

Peng

Lin

et al. 2015

International Journal of Heat and Mass Transfer

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“…Experiments with heat transfer on concave surfaces indicate that the Nusselt number can increase by 100-150% (Mayle, Blair & Kopper 1979;Floryan 1991). By analogy between momentum and heat transfer, an increase in heat flux at the wall implies also an increase in wall shear stress.…”

Section: Introductionmentioning

confidence: 99%

Near-field flow structure of a confined wall jet on flat and concave rough walls

Albayrak¹,

Hopfinger²,

Lemmin³

2008

J. Fluid Mech.

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Experimental results are presented of the mean flow and turbulence characteristics in the near field of a plane wall jet issuing from a nozzle onto flat and concave walls consisting of fixed sand beds. This is a flow configuration of interest for sediment erosion, also referred to as scouring. The measurements were made with an acoustic profiler that gives access to the three components of the instantaneous velocities. For the flat-wall flow, it is shown that the outer-layer spatial growth rate and the maxima of the Reynolds stresses approach the values accepted for the far field of a wall jet at a downstream distance x/b 0 ≈ 8. These maxima are only about half the values of a plane free jet. This reduction in Reynolds stresses is also observed in the shear-layer region, x/b 0 < 6, where the Reynolds shear stress is about half the value of a free shear layer. At distances x/b 0 > 11, the maximum Reynolds shear stress approaches the value of a plane free jet. This change in Reynolds stresses is related to the mean vertical velocity that is negative for x/b 0 < 8 and positive further downstream. The evolution of the inner region of the wall jet is found to be in good agreement with a previous model that explicitly includes the roughness length.On the concave wall, the mean flow and the Reynolds stresses are drastically changed by the adverse pressure gradient and especially by the development of Görtler vortices. On the downslope side of the scour hole, the flow is nearly separating with the wall shear stress tending to zero, whereas on the upslope side, the wall-friction coefficient is increased by a factor of about two by Görtler vortices. These vortices extend well into the outer layer and, just above the wall, cause a substantial increase in Reynolds shear stress.

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“…It is understood that the heat transfer to a concave surface is higher and the heat transfer to a convex surface is lower than the heat transfer to a flat surface. 25 However, as the magnitudes of deviation are about the same, the overall effect of the duct curvature may be neglected for our purposes.…”

Section: Heat Loss In the Inlet Flow Pathmentioning

confidence: 99%

Inflow Disk Generator for Open-Cycle MHD Power Generation

Nakamura

Eustis

1983

Journal of Energy

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A feasibility study of the inflow disk MHD generator for baseload applications was performed. Each design element, i.e., the combustor, inlet flow path, generator channel, diffuser, and magnet, was studied in detail in order to provide a comprehensive assessment of the overall system. Based on these results, the performance of the inflow disk generator was calculated for three different thermal inputs: 1250, 2000, and 2500 MW ( . It was shown that the performance of the inflow disk generator is similar to that of the diagonal generator within the uncertainty of the analysis. Nomenclature 7 X = spectral absorption coefficient C f = friction coefficient ? xb = Planck's spectral distribution of emissive power H = enthalpy L e = mean beam length p r = Prandtl number ? = heat flux = nozzle radius Re Dc = Reynolds number based on the combustor diameter St = Stanton number 4 = velocity i > = distance normal to wall x = angle between wall and axis 3 = effective emissivity of the gas : = emissivity of surface ? = momentum thickness, rO = {" (pu/p e u e ) (1 -u/u e ) (r-ycosa)dy JL = viscosity > = density 7 = Stefan-Boltzmann constant t> = energy thickness, r(Subscripts iw = adiabatic wall condition ? = condition at freestream edge of boundary layer = initial condition = reference state = stagnation condition to -stagnation condition at reservoir w = wall conditions

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Turbulent Boundary Layer Heat Transfer on Curved Surfaces

Cited by 52 publications

References 0 publications

Experimental study of jet impingement heat transfer on a variable-curvature concave surface in a wing leading edge

Experimental study of jet impingement heat transfer on a variable-curvature concave surface in a wing leading edge

Near-field flow structure of a confined wall jet on flat and concave rough walls

Inflow Disk Generator for Open-Cycle MHD Power Generation

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