scholarly journals Natural Convection in a Vertical Annulus with Constant Heat Flux on the Inner Wall.(Dept.M)

2021 ◽  
Vol 23 (2) ◽  
pp. 1-15
Author(s):  
M. El-Kady ◽  
F. Araid
Keyword(s):  
Heat Flux ◽  
Natural Convection ◽  
Constant Heat Flux ◽  
Constant Heat ◽  
Vertical Annulus

Natural Convection of Cold Water in a Vertical Annulus With Constant Heat Flux on the Inner Wall

1990 ◽  
Vol 112 (1) ◽  
pp. 117-123 ◽  
Author(s):  
C. J. Ho ◽  
Y. H. Lin
Keyword(s):  
Heat Flux ◽  
Fluid Flow ◽  
Natural Convection ◽  
Boundary Conditions ◽  
Cold Water ◽  
Flow Behavior ◽  
Constant Heat Flux ◽  
Flow Structures ◽  
Constant Heat ◽  
Vertical Annulus

A numerical solution for steady laminar natural convection of cold water in a vertical annulus with a constant-heat-flux heated inner wall and an isothermally cooled outer wall is examined. Results are generated for flow in annuli with aspect ratio 0.5 ≤ A ≤8, the radius ratio varying between 1.2 and 10, and the density inversion parameter ranging from −2 and 1 for 103 ≤ Ra* ≤ 106. The heat and fluid flow structures of cold water are vividly visualized by means of contour maps of heatlines and streamlines. The results clearly indicate that the mixed boundary conditions considered can have a significant influence on the geometric dependence of heat transfer characteristics and fluid flow structures in comparison with those reported for isothermal boundary conditions. Multicellular flow behavior of cold water can arise in a tall annulus of A = 8.

Effects of Viscous Dissipation and Radiation on MHD Natural Convection in Oblique Porous Cavity with Constant Heat Flux

2017 ◽  
Vol 9 (2) ◽  
pp. 463-484 ◽  
Author(s):  
Ammar I. Alsabery ◽  
Habibis Saleh ◽  
Ishak Hashim
Keyword(s):  
Heat Flux ◽  
Natural Convection ◽  
Viscous Dissipation ◽  
Inclination Angle ◽  
Hartmann Number ◽  
Constant Heat Flux ◽  
Governing Equations ◽  
Constant Heat ◽  
Left Wall ◽  
Porous Cavity

AbstractEffects of viscous dissipation and radiation on MHD natural convection in oblique porous cavity with constant heat flux is studied numerically in the present article. The right inclined wall is maintained at a constant cold temperatureTcand the left inclined wall has a constant heat fluxqwith lengthS, while the remainder of the left wall is adiabatic. The horizontal walls are assumed to be adiabatic. The governing equations are obtained by applying the Darcy model and Boussinesq approximations. COMSOL's finite element method is used to solve the non-dimensional governing equations together with specified boundary conditions. The governing parameters of this study are Rayleigh number (Ra=10,100,200,250,500 and 1000), Hartmann number (0≤Ha≤20), inclination angle of the magnetic field (0° ≤ω≤π/2), Radiation (0≤R≤15), the heater flux length (0.1≤H≤1) and inclination angle of the sloping wall (–π/3≤ϕ≤π/3). The results are considered for various values of the governing parameters in terms of streamlines, isotherms and averageNusselt number. It is found that the intensity of the streamlines and the isotherm patterns decrease with an increment in Hartmann number. The overall heat transfer is significantly increased with the increment of the viscous dissipation and the radiation parameters.

Three-Dimensional Numerical Analysis for Convection of Air in a Bore Space of a Superconducting Magnet

2003 ◽  
Author(s):  
G. Tomita ◽  
M. Kaneda ◽  
T. Tagawa ◽  
H. Ozoe
Keyword(s):  
Magnetic Field ◽  
Heat Flux ◽  
Natural Convection ◽  
Numerical Analysis ◽  
Strong Magnetic Field ◽  
Three Dimensional ◽  
Superconducting Magnet ◽  
Constant Heat Flux ◽  
Constant Heat ◽  
Magnetizing Force

Three-dimensional numerical computations were carried out for the natural convection of air in a horizontal cylindrical enclosure in a magnetic field, which is modeled for a bore space of a horizontal superconducting magnet. The enclosure was cooled from the circumferential sidewall at the constant heat flux and vertical end walls were thermally insulated. A strong magnetic field was considered by a one-turn electric coil with the concentric and twice diameter of the cylinder. Without a magnetic field, natural convection occurs along the circumferential sidewall. When a magnetic field was applied, magnetizing force induced the additional convection, that is, the cooled air at the circumferential wall was attracted to the location of a coil. Consequently, the temperature around the coil decreased extensively.

Natural Convection Local Heat Transfer on Constant-Heat-Flux Inclined Surfaces

1969 ◽  
Vol 91 (4) ◽  
pp. 511-516 ◽  
Author(s):  
G. C. Vliet
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Natural Convection ◽  
Plate Theory ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Constant Heat Flux ◽  
Constant Heat ◽  
Transfer Data ◽  
Inclined Surfaces

Experimental local heat transfer data are presented for natural convection on constant-heat-flux inclined surfaces using water and air. The data extend to Grz* Pr = 1016, cover angles from the vertical to 30 deg with the horizontal, and include the laminar, transition, and turbulent regimes. In the laminar regime the data correlate well with vertical plate theory when the gravitational component parallel to the surface is used. Transition is strongly affected by inclination, the transition Grz* Pr decreasing from near 1013 for vertical surfaces to approximately 108 for a surface at 30 deg to the horizontal. The turbulent local heat transfer data correlate using the actual gravity rather than the parallel component, and indicates a change in the Grz* Pr exponent from near 0 22 for a vertical surface to approximately 1/4 as the inclination decreases. The turbulent data can be correlated quite well by Nuz = 0.30(Grz* Pr)0.24.

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