scholarly journals Natural Convection in a Square Cavity in the Presence of Heated Plate

2007 ◽  
Vol 12 (2) ◽  
pp. 203-212 ◽  
Author(s):  
P. Kandaswamy ◽  
J. Lee ◽  
A. K. Abdul Hakeem
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Aspect Ratio ◽  
Thin Plate ◽  
Convection Heat Transfer ◽  
Working Fluid ◽  
Heated Plate ◽  
Square Cavity ◽  
Aspect Ratios ◽  
Alternating Direction

Natural convection heat transfer in a square cavity induced by heated plate is studied numerically. Top and bottom of the cavity are adiabatic, the two vertical walls of the cavity have constant temperature lower than the plate’s temperature. The flow is assumed to be two-dimensional. The discretized equations were solved by finite difference method using Alternating Direction Implicit technique and Successive OverRelaxation method. The study was performed for different values of Grashof number ranging from 103 to 105 for different aspect ratios and position of heated plate. Air was chosen as a working fluid (Pr = 0.71). The effect of the position and aspect ratio of heated plate on heat transfer and flow were addressed. With increase of Gr heat transfer rate increased in both vertical and horizontal position of the plate. When aspect ratio of heated thin plate is decreased the heat transfer also decreases. For the vertical situation of thin plate heat transfer becomes more enhanced than for horizontal situation.

Numerical Prediction of Heat Transfer from Heated Thin Plate in a Square Cavity by Using LBM

2013 ◽  
Vol 315 ◽  
pp. 531-535 ◽  
Author(s):  
E.P. Kermani ◽  
Arman Safdari ◽  
C.S. Nor Azwadi
Keyword(s):  
Heat Transfer ◽  
Lattice Boltzmann ◽  
Numerical Scheme ◽  
Convection Heat Transfer ◽  
Working Fluid ◽  
Heated Plate ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Square Cavity ◽  
Volume Method

In this paper, natural convection heat transfer from heated plate positioned in square cavity vertically and horizontally was studied. Thermal BGK lattice Boltzmann numerical scheme was applied. The simulation was launched for different aspect ratio A=0.4 and 0.6 at Grasshof numbers and . Air was chosen as working fluid (Pr=0.71). Good arrangement was obtained between the present work and pervious approach using finite volume method. It is found that convection upper side of plate is increase as Grasshof number is increased.

Natural Convection Heat Transfer Through Inclined Longitudinal Slots

1984 ◽  
Vol 106 (4) ◽  
pp. 824-829 ◽  
Author(s):  
J. G. Symons ◽  
M. K. Peck
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Aspect Ratio ◽  
Convective Flow ◽  
Convection Heat Transfer ◽  
Flow Measurements ◽  
Transfer Rates ◽  
Isothermal Surface ◽  
Aspect Ratios ◽  
The Difference

The convective rates of heat transfer through inclined longitudinal slots is studied for the case where heat is transferred from a lower heated isothermal surface, through the slots, to an upper cooled isothermal surface. Experimental data are given for longitudinal slots having aspect ratios from 6–12, slot heights of 25–60 mm, inclinations from horizontal to vertical, and Ra < 107. Data are also given for a transverse slot of aspect ratio 6, for inclinations from horizontal to vertical, and Ra < 107. It is shown that convective heat transfer rates are essentially independent of slot orientation for inclinations up to 15 deg from the horizontal, but longitudinal slots are more effective in suppressing natural convection than transverse slots with the same aspect ratio, for inclinations from 24 to 75 deg from the horizontal. The difference in heat transfer rates for longitudinal and transverse slots inclined between 24 and 75 deg from the horizontal are shown to be due to different convective flows occurring in each slot. The heat flow measurements are supported by convective flow visualization experiments which demonstrate the modes of convective flow within slots.

Natural Convection Heat Transfer in Moderate Aspect Ratio Enclosures

1979 ◽  
Vol 101 (4) ◽  
pp. 655-659 ◽  
Author(s):  
B. A. Meyer ◽  
J. W. Mitchell ◽  
M. M. El-Wakil
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Aspect Ratio ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Aspect Ratios

Local and average heat transfer coefficients for natural convection between parallel plates separated by slats to create enclosures of moderate aspect ratio have been experimentally determined using an interferometric technique. The effects of Rayleigh number, tilt and slat angle, and aspect ratio on the Nusselt number have been determined. The Rayleigh number range tested was up to 7 × 104, and the aspect ratio (ratio of enclosure length to plate spacing) varied between 0.25 and 4. The angles of tilt of the enclosure with respect to the horizontal were 45, 60 and 90 deg. Slat angles of 45, 60, 90 and 135 deg were studied. The results obtained in a previous investigation [1] for aspect ratios of 9 to 36 are included to show continuity. The results indicate that the convective heat transfer is a strong function of the aspect ratio for aspect ratios less than 4. For aspect ratios in the range of 0.5 to 4, spacers between the plates increase, rather than decrease, natural convection heat transfer compared to that for long enclosures. Slat angles less than 90 deg (i.e., oriented downward) reduce convective heat transfer.

Laminar Natural Convection Heat Transfer in a Differentially Heated Square Cavity Due to a Thin Fin on the Hot Wall

2003 ◽  
Vol 125 (4) ◽  
pp. 624-634 ◽  
Author(s):  
Xundan Shi ◽  
J. M. Khodadadi
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Computational Study ◽  
Convection Heat Transfer ◽  
Square Cavity ◽  
Left Wall ◽  
Flow Modification ◽  
Laminar Natural Convection ◽  
Rayleigh Numbers ◽  
Blockage Effect

A finite-volume-based computational study of steady laminar natural convection (using Boussinesq approximation) within a differentially heated square cavity due to the presence of a single thin fin is presented. Attachment of highly conductive thin fins with lengths equal to 20, 35 and 50 percent of the side, positioned at 7 locations on the hot left wall were examined for Ra=104,105,106, and 107 and Pr=0.707 (total of 84 cases). Placing a fin on the hot left wall generally alters the clockwise rotating vortex that is established due to buoyancy-induced convection. Two competing mechanisms that are responsible for flow and thermal modifications are identified. One is due to the blockage effect of the fin, whereas the other is due to extra heating of the fluid that is accommodated by the fin. The degree of flow modification due to blockage is enhanced by increasing the length of the fin. Under certain conditions, smaller vortices are formed between the fin and the top insulated wall. Viewing the minimum value of the stream function field as a measure of the strength of flow modification, it is shown that for high Rayleigh numbers the flow field is enhanced regardless of the fin’s length and position. This suggests that the extra heating mechanism outweighs the blockage effect for high Rayleigh numbers. By introducing a fin, the heat transfer capacity on the anchoring wall is always degraded, however heat transfer on the cold wall without the fin can be promoted for high Rayleigh numbers and with the fins placed closer to the insulated walls. A correlation among the mean Nu, Ra, fin’s length and its position is proposed.

Natural Convection of Cu-Gallium Nanofluid in Enclosures

2011 ◽  
Vol 133 (12) ◽  
Author(s):  
Cong Qi ◽  
Yurong He ◽  
Yanwei Hu ◽  
Juancheng Yang ◽  
Fengchen Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Nusselt Number ◽  
Natural Convection ◽  
Aspect Ratio ◽  
Convection Heat Transfer ◽  
Low Velocity ◽  
Grashof Number ◽  
Aspect Ratios ◽  
Wide Range ◽  
Temperature Dependent Properties

In this work, the natural convection heat transfer of Cu-gallium nanofluid in a differentially heated enclosure is investigated. A single-phase model is employed with constant or temperature-dependent properties of the fluid. The results are shown over a wide range of Grashof numbers, volume fractions of nanoparticles, and aspect ratios. The Nusselt number is demonstrated to be sensitive to the aspect ratio. It is found that the Nusselt number is more sensitive to thermal conductivity than viscosity at a low velocity (especially for a low aspect ratio and a low Grashof number), however, it is more sensitive to the viscosity than the thermal conductivity at a high velocity (high aspect ratio and high Grashof number). In addition, the evolution of velocity vectors, isotherms, and Nusselt number for a small aspect ratio is investigated.

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