Heat Transfer Around a Circular Cylinder Near a Plane Surface

1985 ◽  
Vol 107 (4) ◽  
pp. 916-921 ◽  
Author(s):  
S. Aiba
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Experimental Study ◽  
Reynolds Number ◽  
Circular Cylinder ◽  
Boundary Layer Thickness ◽  
Plane Surface ◽  
Cross Flow ◽  
Nusselt Numbers ◽  
Characteristic Features

An experimental study has been conducted on the effect of the clearance (c) between a circular cylinder and a plane surface on the heat transfer from the cylinder to a cross flow of air. The test cylinder diameters (d) were 10.1, 15.2, and 25.2 mm. The turbulent boundary layer thickness (δ) along the wall with no cylinder present was varied from 15 to 19 mm. The Reynolds number (Re) based on the undisturbed uniform flow velocity above the wall ranged from 104 to 6.6×104. Variations of the characteristic features of the local and mean Nusselt numbers are discussed in relation to the values c/d, δ/d, and Re investigated.

Heat Transfer Around a Tube in In-Line Tube Banks Near a Plane Wall

1990 ◽  
Vol 112 (4) ◽  
pp. 933-938 ◽  
Author(s):  
S. Aiba
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Reynolds Number ◽  
Boundary Layer Thickness ◽  
Plane Wall ◽  
Circular Cylinders ◽  
The Third ◽  
Compact Expression ◽  
Characteristic Features ◽  
Tube Banks

Heat transfer in the third cylinder of four circular cylinders above a plane wall has been investigated in a crossflow of air. The turbulent boundary layer thickness along the wall with no cylinder present was about 21 mm. The cylinder diameter (d) was 15 mm, the clearance (c) between the cylinders and the wall was 0.75 ~ 60 mm (c/ d = 0.05 ~ 4.0), and the pitch (p) (which denotes the longitudinal spacing between cylinder centers) was 18 ~ 66 mm (p/d = 1.2 ~ 4.4). The Reynolds number (Re) based on the undisturbed uniform flow velocity above the wall ranged from 0.8 × 104 ~ 4 × 104. Variations in the characteristic features of local and mean Nusselt number Num are discussed in relation to c/d, p/d, and Re. Num yielded the compact expression Num = 0.103 (p/d)−0.12(c/d)0.23Re0.74, with a spread of ±5 percent in the ranges c/d = 0.18 ~ 0.61, p/d = 1.2 ~ 3.2, and Re = 0.8 × 104 ~ 4 × 104, except for the case with c/d = 0.18, p/d = 3.2.

Effect of Sound on Heat Transfer from a Horizontal Circular Cylinder at Large Wavelengths

1965 ◽  
Vol 7 (2) ◽  
pp. 127-130 ◽  
Author(s):  
B. H. Lee ◽  
P. D. Richardson
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Circular Cylinder ◽  
Layer Thickness ◽  
Boundary Layer Thickness ◽  
Sound Field ◽  
Practical Relevance ◽  
Local Effects ◽  
Horizontal Circular Cylinder ◽  
Standing Sound

The practical relevance of investigations of the effect of oscillations on convective heat transfer is discussed. Some experiments on overall heat transfer from a horizontal heated circular cylinder in a transverse, horizontal standing sound field are reported. Observations of local effects of sound on boundary layer thickness and heat transfer are described, and a correlation of heat transfer spanning all sound intensities is suggested in the light of these observations. The correlation is fitted well by the data, and thus provides adducive evidence for the explanation of the phenomena observed.

Flow and Heat Transfer in Convectively Cooled Underground Electric Cable Systems: Part 2—Temperature Distributions and Heat Transfer Correlations

1978 ◽  
Vol 100 (1) ◽  
pp. 36-40 ◽  
Author(s):  
R. S. Abdulhadi ◽  
J. C. Chato
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Reynolds Number ◽  
Cross Section ◽  
Thermal Boundary Layer ◽  
Electric Cable ◽  
Nusselt Numbers ◽  
Temperature Distributions ◽  
Cable Systems ◽  
Heat Transfer Correlations

Temperature distributions and heat transfer correlations have been obtained experimentally for a wide range of physical, flow and thermal parameters in three models of oil-cooled underground electric cable systems. The results show that in the laminar range, with the oils used, the thermal boundary layer thickness around the heated cables is only of the order of 2–3 mm over the entire length of the test section. Consequently, the best correlation of the heat transfer results is obtained if the Nusselt number, based on the cable diameter, is plotted against Re·Pr0.4, where the Reynolds number is based on the overall hydraulic diameter of the cross section of the flow. For laminar flows, the oil temperatures in the restricted flow channels between three cables or two cables and the pipe wall are about 11°C higher than corresponding bulk temperatures. As the flow becomes turbulent, the thermal boundary layer tends to vanish and the oil temperature becomes uniform over the entire flow cross section. Laminar Nusselt numbers are independent of the skid wire roughness ratio and the flow Reynolds number, but increase with increasing Rayleigh number and axial distance from the inlet, indicating significant natural convection effect. The range of laminar Nusselt numbers was 5–16. Turbulent Nusselt numbers increase with increasing roughness ratios. The Nusselt numbers at Re = 3000 are 30 and 60 for roughness ratios of 0.0216 and 0.0293, respectively.

scholarly journals Unconfined laminar nanofluid flow and heat transfer around a rotating circular cylinder in the steady regime

2017 ◽  
Vol 38 (2) ◽  
pp. 3-20
Author(s):  
Rafik Bouakkaz ◽  
Fouzi Salhi ◽  
Yacine Khelili ◽  
Mohamed Quazzazi ◽  
Kamel Talbi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Circular Cylinder ◽  
Rotation Rate ◽  
Volume Fraction ◽  
Steady Regime ◽  
Volume Fractions ◽  
Nusselt Numbers ◽  
Rotating Circular Cylinder ◽  
Flow And Heat Transfer

AbstractIn this work, steady flow-field and heat transfer through a copper- water nanofluid around a rotating circular cylinder with a constant nondimensional rotation rate α varying from 0 to 5 was investigated for Reynolds numbers of 5–40. Furthermore, the range of nanoparticle volume fractions considered is 0–5%. The effect of volume fraction of nanoparticles on the fluid flow and heat transfer characteristics are carried out by using a finite-volume method based commercial computational fluid dynamics solver. The variation of the local and the average Nusselt numbers with Reynolds number, volume fractions, and rotation rate are presented for the range of conditions. The average Nusselt number is found to decrease with increasing value of the rotation rate for the fixed value of the Reynolds number and volume fraction of nanoparticles. In addition, rotation can be used as a drag reduction technique.

Premature boundary layer transition caused by surface static pressure tappings

1988 ◽  
Vol 92 (912) ◽  
pp. 63-68 ◽  
Author(s):  
P. E. Roach ◽  
J. T. Turner
Keyword(s):  
Boundary Layer ◽  
Surface Roughness ◽  
Reynolds Number ◽  
Circular Cylinder ◽  
Static Pressure ◽  
Cross Flow ◽  
Boundary Layer Transition ◽  
Layer Transition ◽  
Wide Range ◽  
Boundary Layer Interaction

Summary Experiments have been performed to study the influence of multiple surface static pressure tappings on transition of the boundary layer on a circular cylinder in cross-flow. A wide range of tapping and cylinder dimensions have been examined to demonstrate that the tappings can act in the same way as trip wires or other surface roughness to reduce the Reynolds number at which transition occurs. Hence, the pressure distribution around the cylinder may be influenced by the presence of the tappings, leading to incorrect measurements. Examination of the data has resulted in a correlation which should make it possible to avoid this tapping/boundary layer interaction in future experiments involving similar cylindrical bodies.

Enhanced Forced Convection Heat Transfer From a Cylinder Using Permeable Fins

2003 ◽  
Vol 125 (5) ◽  
pp. 804-811 ◽  
Author(s):  
Bassam A/K Abu-Hijleh
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Forced Convection ◽  
Convection Heat Transfer ◽  
Cross Flow ◽  
Horizontal Cylinder ◽  
Convection Heat ◽  
Transfer Rates ◽  
Forced Convection Heat Transfer ◽  
Nusselt Numbers

The problem of cross-flow forced convection heat transfer from a horizontal cylinder with multiple, equally spaced, high conductivity permeable fins on its outer surface was investigated numerically. The heat transfer characteristics of a cylinder with permeable versus solid fins were studied for several combinations of number of fins and fin height over the range of Reynolds number (5–200). Permeable fins provided much higher heat transfer rates compared to the more traditional solid fins for a similar cylinder configuration. The ratio between the permeable to solid Nusselt numbers increased with Reynolds number and fin height but tended to decrease with number of fins. This ratio was as high as 4.35 at Reynolds number of 150 and a single fin with a nondimensional height of 3.0. The use of 1–2 permeable fins resulted in much higher Nusselt number values than when using up to 18 solid fins. Such an arrangement has other benefits such as a considerable reduction in weight and cost.

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