Generalized thermal resistance for convective heat transfer and its relation to entransy dissipation

2008 ◽  
Vol 53 (23) ◽  
pp. 3753-3761 ◽  
Author(s):  
Qun Chen ◽  
JianXun Ren
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Entransy Dissipation

Microchannel Optimization for Heat Dissipation From a Solid Substrate

2008 ◽  
Author(s):  
C. B. Sobhan ◽  
P. S. Anoop ◽  
Kuriyan Arimboor ◽  
Thomas Abraham ◽  
G. P. Peterson
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Thermal Resistance ◽  
Computational Model ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Heat Dissipation ◽  
Three Dimensional ◽  
Solid Substrate ◽  
Nusselt Numbers

A computational model was developed to analyze and optimize the convective heat transfer for water flowing through rectangular microchannels fabricated in a silicon substrate. A baseline case was analyzed by solving the nondimensional governing equations. Using a quasi three-dimensional computational model, the velocity and temperature distributions were obtained and the numerical results were then used to determine the overall dimensionless thermal resistance for the convective heat transfer from the substrate to the fluid. To validate the numerical model, the average Nusselt numbers as determined by the numerical model were compared with experimental results available in the literature, for channels with comparable hydraulic diameters. The procedure for arriving at an optimum geometric configuration and arrangement of microchannels on the substrate, subject to given design constraints, so that the thermal resistance is at a minimum, is described and demonstrated using the computational model.

Thermal Behavior of Nominally Flat Silicon-Based Heat Spreaders

2005 ◽  
Vol 128 (4) ◽  
pp. 370-379
Author(s):  
Ta-Wei Lin ◽  
Ming-Chang Wu ◽  
Cheng-Hsien Peng ◽  
Po-Li Chen ◽  
Ying-Huei Hung
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Thermal Resistance ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Heat Spreader ◽  
Heat Spreaders ◽  
Silicon Based ◽  
Maximum Thermal Resistance ◽  
Effect Of Surface

Thermal characteristics for a horizontal heated chip mounted with three types of nominally flat silicon-based heat spreaders have been systematically investigated. They include the natural convective and radiative heat transfer from the top surface of the heat spreaders to the external ambient, external thermal resistance, and maximum overall thermal resistance. In the aspect of natural convection, an axisymmetric bowl-shaped profile of local Nusselt number is achieved, and the highest convective heat transfer performance occurs at the location near the rim of the heat spreader. The effect of surface roughness on both local and average natural convective heat transfer behaviors from nominally flat silicon-based spreader surfaces to the external ambient is not significant. Two new generalized correlations of local and average Nusselt numbers for various heat spreader surfaces are presented. The contributions of convection and radiation on the total heat dissipated from the top surface of the heat spreader to the ambient are about 72% and 28%, respectively. The effect of surface roughness on external thermal resistance for nominally flat silicon-based surfaces is not significant. The influence of the conductive thermal resistance within the silicon-based heat spreader on the maximum thermal resistance is not significant. The maximum thermal resistance is mainly dominated by external thermal resistance for flat nominally silicon-based heat spreaders.

A Study on the Convective Heat Transfer Coefficient and Thermal Resistance of Clothing under Cross Ventilation

2011 ◽  
Vol 10 (2) ◽  
pp. 155-162
Author(s):  
Keiko Sato ◽  
Takashi Kurabuchi ◽  
Takeshi Ogasawara ◽  
Masaaki Ohba ◽  
Shizuo Iwamoto ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Resistance ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Convective Heat Transfer Coefficient

Thermal Performance of Triangular Folded Fin Heat Sinks in a Duct

2003 ◽  
Author(s):  
Seo Young Kim ◽  
Taeho Ji ◽  
Dong Gyu Choi ◽  
Byung Ha Kang
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Flow Velocity ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Thermal Performance ◽  
Heat Sink ◽  
Base Plate ◽  
Heat Sinks ◽  
Heat Transfer Characteristics

Experiments have been carried out to investigate the convective heat transfer characteristics from triangular folded fin heat sinks in a suction-type fan duct. The dimension of the triangular folded fin heat sinks is 62 mm in height with a 12 mm thick base plate, 292 mm in width, and 447 mm in length. The inlet flow velocity is varied in the range of 0.6–5.3 m/s. Thermal performance of triangular folded fin heat sinks is evaluated in terms of thermal resistance of heat sinks according to flow velocity and fan power. The results obtained show that the present triangular folded-fin heat sink shows a higher thermal performance compared to a conventional extruded plate-fin heat sink. Especially, a perforated slit folded-fin heat sink displays a lower thermal resistance. As the number of slit fabricated on the perforated folded fins increases, thermal performance is more pronounced.

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