Local heat-transfer coefficients on a uniformly heated cylinder

Perkins, H. C.; Leppert, G.

doi:10.1016/0017-9310(64)90079-1

Cited by 70 publications

(21 citation statements)

References 11 publications

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“…On the front part of the cylinder (up to θ ≈ 40 deg), there is no appreciable effect of boundary condition. Higher heat transfer coefficients have also been observed experimentally by Perkins and Leppert 18 for a blockage ratio of 0.41 with the isoflux boundary condition.…”

Section: Heat Transfer Characteristicssupporting

confidence: 60%

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Fluid Flow And Heat Transfer from a Cylinder Between Parallel Planes

Khan

Culham

Yovanovich

2004

Journal of Thermophysics and Heat Transfer

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An integral approach is employed to investigate the effects of blockage on fluid flow and heat transfer from a circular cylinder confined between parallel planes. The integral form of the boundary-layer momentum equation is solved using the modified von Kármán-Pohlhausen method, which uses a fourth-order velocity profile inside the hydrodynamic boundary layer. The potential flow velocity, outside the boundary layer, is obtained by the method of images. A third-order temperature profile is used in the thermal boundary layer to solve the energy integral equation for isothermal and isoflux boundary conditions. Closed-form solutions are obtained for the fluid flow and heat transfer from the cylinder with blockage ratio and Reynolds and Prandtl numbers as parameters. It is shown that the blockage ratio controls the fluid flow and the transfer of heat from the cylinder and delays the separation. The results for both thermal boundary conditions are found to be in a good agreement with experimental/numerical data for a single circular cylinder in a channel.

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Section: Heat Transfer Characteristicssupporting

confidence: 60%

“…Perkins and Leppert 18 investigated local heat transfer coefficients from a uniformly heated cylinder with water in crossflow. They used both potential flow and experimental pressure distributions to investigate and correlate the effects of blockage on the velocity and heat transfer distributions.…”

mentioning

confidence: 99%

Fluid Flow And Heat Transfer from a Cylinder Between Parallel Planes

Khan

Culham

Yovanovich

2004

Journal of Thermophysics and Heat Transfer

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“…The effect of Prandtl number on the rate of heat transfer from the cylinder is shown in Fig. 8 [25,26] and for square cylinders [9]. For instance, Sharma and Eswaran [9] have proposed a correlation for the flow over a square cylinder for both these thermal boundary conditions for Re = 5-160 but for a single value of the Prandtl number, i.e., 0.7.…”

Section: Time Historymentioning

confidence: 97%

Effects of Reynolds and Prandtl numbers on heat transfer from a square cylinder in the unsteady flow regime

Sahu

Chhabra

Eswaran

2009

International Journal of Heat and Mass Transfer

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“…The value of N u (angle-average of N u) changes always by less than 0.2% for all our measurements depending on whether the correction for thermal conduction is applied or not. Perkins and Leppert (1964) concluded that for their resistively-heated thin wall tube, the correction for thermal conduction in the circumferential direction was small and it applied just in one or two angular positions in their experiment (similarly to the case of the present experiment);…”

Section: Velocity and Heat Transfer Measurementsmentioning

confidence: 96%

Heat Transfer Enhancement by Grid-Generated Turbulence for a Cylinder in Crossflow

Melina

Bruce

Hewitt

et al. 2016

Springer Proceedings in Physics

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Heat transfer measurements around the centreline circumference of a cylinder in crossflow are performed in a wind tunnel. The cylinder is placed at several stations downstream of three turbulence-generating grids with different geometries and different blockage ratios σ g : a regular grid (RG60) with σ g = 32%, a fractal-square grid (FSG17) with σ g = 25% and a singlesquare grid (SSG) with σ g = 20%. Measurements are performed at 20 stations for 3 nominal Reynolds numbers (based on the diameter D of the cylinder) Re ∞ = 11 100, 24 500, 37 900. Hot-wire measurements are performed along the centreline, without the cylinder in place, to characterise the flow downstream of the grids. The extent of the turbulence production region, where the turbulence intensity T u increases with the streamwise distance x from the grid, is higher for SSG and more so for FSG17 than for RG60. The angular profiles of the Nusselt number N u are measured in the production regions of these two grids and are compared to those obtained in the decay regions, where T u decreases with x. This comparison is made at locations with approximately same T u. It is found that, for SSG, N u/Re 0.5 on the front of the cylinder (boundary layer region) is lower in the production region than in the decay region. This is explained by the presence of clear and intense vortex shedding in the production region of SSG which reduces the turbulent fluctuations which are "effective" in enhancing the heat transfer across a laminar boundary layer. For higher Re ∞ , the values of N u/Re 0.5 on the front of the cylinder are higher in the production region of FSG17 than in that of SSG, despite T u being higher for SSG. This is consistent with a lower intermittency of the flow for FSG17 caused by the presence of the fractal geometrical iterations. The recovery of N u on the back of the cylinder (wake region) is appreciably higher in the production region than in the decay region for both FSG17 and for SSG. This can be due to the lower integral length scale ratio L u /D in the production region and suggests, for the same Re ∞ , a reduction of the vortex formation length downstream of the cylinder, possibly promoted by the interaction between the wakes of the bars of the grid and the wake of the cylinder. At a large distance from the grids, the heat transfer enhancement is higher and it is more efficient for FSG17 and for SSG than for RG60. For high values of x in the turbulence decay region of the grids, the values of N u (circumferential average of N u) are similar for FSG17 and for SSG and they are both appreciably higher than for RG60. This happens despite both FSG17 and SSG having a lower blockage ratio than RG60. The use of FSG17 has the practical advantage of combining high heat transfer rates on the cylinder with a weak vortex shedding from the grid.Keywords: forced convection; circular cylinder; grid-generated turbulence * Email address for correspondence: g.melina13@imperial.ac.uk 1 Nomenclature a 1 Strain rate parameter

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Local heat-transfer coefficients on a uniformly heated cylinder

Cited by 70 publications

References 11 publications

Fluid Flow And Heat Transfer from a Cylinder Between Parallel Planes

Fluid Flow And Heat Transfer from a Cylinder Between Parallel Planes

Effects of Reynolds and Prandtl numbers on heat transfer from a square cylinder in the unsteady flow regime

Heat Transfer Enhancement by Grid-Generated Turbulence for a Cylinder in Crossflow

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