NATURAL CONVECTION HEAT TRANSFER IN A NANOFLUID-FILLED HORIZONTAL LAYER WITH SINUSOIDAL WALL TEMPERATURE AT THE BOTTOM BOUNDARY

2018 ◽  
Vol 49 (11) ◽  
pp. 1059-1076
Author(s):  
G. Wang ◽  
Z. L. Fan ◽  
Min Zeng ◽  
Qiu-Wang Wang ◽  
H. Ozoe
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Wall Temperature ◽  
Convection Heat Transfer ◽  
Horizontal Layer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Bottom Boundary ◽  
Sinusoidal Wall

Effect of spatial side-wall temperature variation on transient natural convection of a nanofluid in a trapezoidal cavity

2017 ◽  
Vol 27 (6) ◽  
pp. 1365-1384 ◽  
Author(s):  
Ammar I. Alsabery ◽  
Ishak Hashim ◽  
Ali J. Chamkha ◽  
Habibis Saleh ◽  
Bilal Chanane
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Temperature Variation ◽  
Wall Temperature ◽  
Convection Heat Transfer ◽  
Side Wall ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Content Type ◽  
Transient Natural Convection

Purpose This paper aims to study analytically and numerically the problem of transient natural convection heat transfer in a trapezoidal cavity with spatial side-wall temperature variation. Design/methodology/approach The governing equations subject to the initial and boundary conditions are solved numerically by the finite difference scheme consisting of the alternating direction implicit method and the tri-diagonal matrix algorithm. The left sloping wall of the cavity is heated to non-uniform temperature, and the right sloping wall is maintained at a constant cold temperature, while the horizontal walls are kept adiabatic. Findings It is shown that the heat transfer rate increases in non-uniform heating increments, whereby low wave number values are more affected by the convection. The best heat transfer enhancement results from larger side wall inclination angle; however, trapezoidal cavities require longer time compared to that of square to reach steady state. Originality/value The study of natural convection heat transfer in a trapezoidal cavity filled with nanofluid and heated by spatial side-wall temperature has not yet been undertaken. Thus, the authors of the present study believe that this work is valuable.

Pseudo-Steady-State Natural Convection Heat Transfer Inside a Vertical Cylinder

1986 ◽  
Vol 108 (2) ◽  
pp. 310-316 ◽  
Author(s):  
Y. S. Lin ◽  
R. G. Akins
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Wall Temperature ◽  
Convection Heat Transfer ◽  
Vertical Cylinder ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Constant Wall Temperature ◽  
Stream Functions

The SIMPLER numerical method was used to calculate the pseudo-steady-state natural convection heat transfer to a fluid inside a closed vertical cylinder for which the boundary temperature was spatially uniform and the temperatures throughout the entire system were increasing at the same rate. (Pseudo-steady state is comparable to the steady-state problem for a fluid with uniform heat generation and constant wall temperature.) Stream functions, temperature contours, axial velocities, and temperature profiles are presented. The range of calculation was 0.25 < H/D < 2, Ra < 107, and Pr = 7. This range includes conduction to weak turbulence. A characteristic length defined as 6 × (volume)/(surface area) was used since it seemed to produce good regression results. The overall heat transfer for the convection-dominated range was found to be correlated by Nu = 0.519 Ra0.255, where the temperature difference for both the Nusselt and Rayleigh numbers was the center temperature minus the wall temperature. Correlations using other temperature differences are also presented for estimating the volumetric mean and minimum temperatures.

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