Natural Convection Heat Transfer in a Rotating Enclosure with Three Rows of Discrete Heat Sources

2006 ◽  
Vol 37 (5) ◽  
pp. 395-405 ◽  
Author(s):  
L. F. Jin ◽  
C. P. Tso ◽  
K. W. Tou
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Heat Sources ◽  
Convection Heat ◽  
Discrete Heat Sources

Use of Nanofluids for Enhanced Natural Cooling of Discretely Heated Enclosures

2013 ◽  
Vol 302 ◽  
pp. 422-428
Author(s):  
Rached Ben-Mansour ◽  
Mohammed A. Habib
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Convection Heat Transfer ◽  
Particle Dispersion ◽  
Natural Convection Heat Transfer ◽  
Heat Sources ◽  
Convection Heat ◽  
Discrete Heat Sources

Natural convection heat transfer from discrete heat sources to nanofluids is of great importance because of its application in the cooling of electronic components. The presence of the nanoparticles in the fluids increases appreciably the effective thermal conductivity of the fluid and consequently enhances the heat transfer characteristics. The present study is aimed to investigate numerically the natural convection heat transfer from discrete heat sources to nanofluids. The behavior of nanofluids was investigated numerically inside a heated cavity to gain insight into convective recirculation and flow processes induced by a nanofluid. A computational model was developed to analyze heat transfer performance of nanofluids inside a cavity taking into account the solid particle dispersion. The model was validated through the comparison with available experimental data. The results showed good agreement. The influence of the solid volume fraction on the flow pattern and heat transfer inside the cavity was investigated. The results show that the intensity of the streamlines increases with the volume fraction. It is also indicated that higher velocities along the centerline of the enclosure are achieved as the volume of nanoparticles increases. The influence of the loading factor is more distinguished at the upper heaters and in particular at the highest heater. The heat transfer increases as the volume fraction of the nanoparticles increases from 2 to 10%.

Influence of Discrete Heat Source Location on Natural Convection Heat Transfer in a Vertical Square Enclosure

1991 ◽  
Vol 113 (3) ◽  
pp. 268-274 ◽  
Author(s):  
G. Refai Ahmed ◽  
M. M. Yovanovich
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Source ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Heat Sources ◽  
Convection Heat ◽  
Square Enclosure ◽  
Discrete Heat Sources ◽  
Scale Length

A numerical study is carried out to investigate the influence of discrete heat sources on natural convection heat transfer in a square enclosure filled with air. The enclosure has two vertical boundaries of height H; one of them is cooled at Tc and the other has discrete heat sources [isoflux (q = c) or isothermal (Th = c)]. The enclosure has two horizontal adiabatic boundaries of length L. Results are reported for 0 ≤ Ra ≤ 106, Pr = 0.72, A = 1, aspect ratio ε, the relative size of the heat source to the total height, lies in the range 0.25 ≤ ε ≤ 1 and the discrete heat sources are located at the top or the bottom of the enclosure. Verification of numerical results is obtained at Ra = 0 (conduction limit) with analytical conduction solutions. In addition, a comparison with experimental and numerical data is made which also shows good agreement. The relationships between both Nu, ΔNu (change of thermal conductance) and Ra based on scale length (the size of the heat source S divided by the aspect ratio A) are also investigated here. A relationship Nu and Ra, based on scale length obtained from analytical solutions is correlated as Nu = Nu(Ra, ε). In addition, extrapolation correlations of Nu over the very high range of Rayleigh numbers (Ra ≥ 108) are developed.

Natural Convection From Protruding Heat Sources in a Channel

2003 ◽  
Author(s):  
Tunc Icoz ◽  
Qinghua Wang ◽  
Yogesh Jaluria
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Natural Convection ◽  
Rayleigh Scattering ◽  
Convection Heat Transfer ◽  
Separation Distance ◽  
Natural Convection Heat Transfer ◽  
Temperature Profiles ◽  
Heat Sources ◽  
Convection Heat

Natural convection has important implications in many applications like cooling of electronic equipment due to its low cost and easy maintenance. In the present study, two-dimensional natural convection heat transfer to air from multiple identical protruding heat sources, which simulate electronic components, located in a horizontal channel has been studied numerically. The fluid flow and temperature profiles, above the heating elements placed between an adiabatic lower plate and an isothermal upper plate, are obtained using numerical simulation. The effects of source temperatures, channel dimensions, openings, boundary conditions, and source locations on the heat transfer from and flow above the protruding sources are investigated. Different configurations of channel dimensions and separation distances of heat sources are considered and their effects on natural convection heat transfer characteristics are studied. The results show that the channel dimensions have a significant effect on fluid flow. However, their effects on heat transfer are found to be small. The separation distance is found to be an important parameter affecting the heat transfer rate. The numerical results of temperature profiles are compared with the experimental measurements performed using Filtered Rayleigh Scattering (FRS) technique in an earlier study, indicating good agreement. It is observed that adiabatic upper plate assumption leads to better temperature predictions than isothermal plate assumption.

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