scholarly journals CONJUGATE CONDUCTION-FREE CONVECTION HEAT TRANSFER FROM A HORIZONTAL CYLINDER

2013 ◽  
Vol 36 (2) ◽  
pp. 155-166
Author(s):  
M. K. Bassiouny ◽  
F. M. Mahfouz ◽  
S. A. Wilson ◽  
Gamal H. Badawy
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Convection Heat Transfer ◽  
Horizontal Cylinder ◽  
Convection Heat ◽  
Free Convection Heat ◽  
Conjugate Conduction

A Comparison Between the Local Free Convection Heat Transfer Coefficients of Horizontal Cylinders in Vertical and Inclined Arrays

2006 ◽  
Author(s):  
Mehdi Ashjaee ◽  
Tooraj Yousefi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Rayleigh Number ◽  
Free Convection ◽  
Convection Heat Transfer ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Horizontal Cylinder ◽  
Convection Heat ◽  
Free Convection Heat

Laminar free convection heat transfer from vertical and inclined arrays of horizontal isothermal cylinders in air was investigated experimentally and numerically. Experiments were carried out using Mach-Zehnder interferometer and the FLUENT code was used for numerical study. Investigation was performed for vertical and horizontal cylinder spacing from 2 to 5 and to 2 cylinder diameter respectively. The Rayleigh number based on the cylinder diameter varied between 103 and 3×103. The effect of vertical and horizontal cylinder spacing and Rayleigh number on the local heat transfer from each individual cylinder was investigated. It was seen that the local heat transfer coefficient of each cylinder strongly depends on its position relative to the others. This variation of the local heat transfer coefficient was explained by the interaction of plume’s temperature and velocity profiles.

On Gaseous Free-Convection Heat Transfer With Well-Defined Boundary Conditions

2000 ◽  
Vol 122 (4) ◽  
pp. 661-668 ◽  
Author(s):  
M. R. D. Davies ◽  
D. T. Newport ◽  
T. M. Dalton
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Free Convection ◽  
Boundary Conditions ◽  
Convection Heat Transfer ◽  
Boussinesq Approximation ◽  
Horizontal Cylinder ◽  
Convection Heat ◽  
Variable Property ◽  
Free Convection Heat

The scaling of free convection heat transfer is investigated. The nondimensional groups for Boussinesq and fully compressible variable property free convection, driven by isothermal surfaces, are derived using a previously published novel method of dimensional analysis. Both flows are described by a different set of groups. The applicability of each flow description is experimentally investigated for the case of the isothermal horizontal cylinder in an air-filled isothermal enclosure. The approach taken to the boundary conditions differs from that of previous investigations. Here, it is argued that the best definition of the boundary conditions is achieved for heat exchange between the cylinder and the enclosure rather than the cylinder and an arbitrarily chosen fluid region. The enclosure temperature is shown both analytically and experimentally to affect the Nusselt number. The previously published view that the Boussinesq approximation has only a limited range of application is confirmed, and the groups derived for variable property compressible free convection are demonstrated to be correct experimentally. A new correlation for horizontal cylinder Nusselt number prediction is presented. [S0022-1481(00)01604-2]

scholarly journals Experimental Investigation of Free Convection Heat Transfer from Horizontal Cylinder to Nanofluids

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2909
Author(s):  
Dorota Sawicka ◽  
Janusz T. Cieśliński ◽  
Slawomir Smolen
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Heat Transfer Performance ◽  
Convection Heat Transfer ◽  
Correlation Equation ◽  
Horizontal Cylinder ◽  
Al2o3 Nanoparticles ◽  
Convection Heat ◽  
Number Range ◽  
Free Convection Heat

The results of free convection heat transfer investigation from a horizontal, uniformly heated tube immersed in a nanofluid are presented. Experiments were performed with five base fluids, i.e., ethylene glycol (EG), distilled water (W) and the mixtures of EG and water with the ratios of 60/40, 50/50, 40/60 by volume, so the Rayleigh (Ra) number range was 3 × 104 ≤ Ra ≤ 1.3 × 106 and the Prandtl (Pr) number varied from 4.4 to 176. Alumina (Al2O3) nanoparticles were tested at the mass concentrations of 0.01, 0.1 and 1%. Enhancement as well as deterioration of heat transfer performance compared to the base fluids were detected depending on the composition of the nanofluid. Based on the experimental results obtained, a correlation equation that describes the dependence of the average Nusselt (Nu) number on the Ra number, Pr number and concentration of nanoparticles is proposed.

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