Orientation effects on thermal performance of radial heat sinks with a concentric ring subject to natural convection

Author(s):  
Bin Li ◽  
Chan Byon
Author(s):  
Bin Li ◽  
Chan Byon

Numerical study is carried out on natural convection heat transfer from three radial heat sinks subject to the influence of orientation. A finite volume method (FVM) numerical model was used to analyze the thermal performance of the radial heat sinks under upward, sideward and downward orientations. The effects of orientation with respect to gravity, fin number (15–30), the thickness of concentric ring (0.15–0.60) and Elenbaas number (15–55) on Nusselt number are investigated. Numerical results indicate that radiation is non-negligible in this study due to its high influence on thermal performance. The Nusselt number is relatively insensitive to the smaller ring thickness. The sideward facing orientation yields the worst thermal performance despite fin number changing. It is found that the thermal performance of heat sinks in upward and downward orientations depend on the number of fins significantly.


Author(s):  
Fernando Cano-Banda ◽  
Ana Gallardo-Gutierrez ◽  
Jesus Garcia-Gonzalez ◽  
Abel Hernandez-Guerrero ◽  
Luis Luviano-Ortiz

A radial design of a passive heat sink for cooling LED illumination devices is analyzed numerically in order to identify the geometric shape that promotes better heat dissipation rates. Natural convection with the surrounding is considered during the operation of the heat sink. Due to the fact that natural convection is the main mechanism of heat transfer, the shape of the heat sink has a high influence in the heat dissipated. An analysis of the influence of different parameters of a heat sink is conducted in the presented study. The radial heat sink under analysis consists in a flat disc with rectangular fins on it, and the fins are distributed with a radial longitudinal orientation in a circular row arrangement. The number of rows can vary but there is a constant relation of two times the number of fins between the number of fins in an inner row and the next outer row. In order to find a correct configuration to improve the dissipation of heat, parameters like the number of fins, the length of the fins and the separation between fins are studied. The average Nusselt number and thermal resistance for each geometric configuration are compared. The output analysis provides the best shape for a maximum heat transfer.


2019 ◽  
Vol 7 (1) ◽  
pp. 43-53
Author(s):  
Abbas Jassem Jubear ◽  
Ali Hameed Abd

The heat sink with vertically rectangular interrupted fins was investigated numerically in a natural convection field, with steady-state heat transfer. A numerical study has been conducted using ANSYS Fluent software (R16.1) in order to develop a 3-D numerical model.  The dimensions of the fins are (305 mm length, 100 mm width, 17 mm height, and 9.5 mm space between fins. The number of fins used on the surface is eight. In this study, the heat input was used as follows: 20, 40, 60, 80, 100, and 120 watts. This study focused on interrupted rectangular fins with a different arrangement and angle of the fins. Results show that the addition of interruption in fins in various arrangements will improve the thermal performance of the heat sink, and through the results, a better interruption rate as an equation can be obtained.


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