scholarly journals Natural-convection heat transfer enhancement of aluminum heat sink using nanocoating by electron beam method

2019 ◽  
Vol 23 (5 Part B) ◽  
pp. 3129-3141
Author(s):  
Senthil Pongiannan ◽  
Velraj Ramalingam ◽  
Latha Nagendran
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Electron Beam ◽  
Natural Convection ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Convection Heat Transfer ◽  
Safety Level ◽  
X Ray ◽  
Beam Method

The high power density and compactness of the next generation electronic devices necessitate efficient and effective cooling methods for heat dissipation in order to maintain the temperature at an acceptable safety level. In the present work, aluminum nanocoating was employed in a heat sink to study the heat transfer performance under natural-convection conditions. The nanocoating was achieved using an electron beam method while the characteristics of nanocoated surfaces were analysed using SEM, an energy dispersive X-ray spectroscopy, surface roughness profilometry equipment and by X-ray diffraction techniques. The heat dissipation from heat sink with and without nanocoating under natural-convection has been experimentally studied at different controllable surrounding temperatures. A uniform increase in the surface roughness by the nanocoating was seen in all cases. The conclusion from several experimental results was that the effect of nanocoating in augmenting the heat transfer is more pronounced only when there is a sufficient temperature driving potential.

A Study on Improving in Natural Convection Heat Transfer for Heat Sink of High Power LEDs

2011 ◽  
Vol 383-390 ◽  
pp. 6834-6839 ◽  
Author(s):  
Xiang Rui Meng ◽  
Xin Ling Ma ◽  
Ji Fu Lu ◽  
Xin Li Wei
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Transfer Performance ◽  
Stagnation Zone ◽  
Convection Heat ◽  
Symmetry Center

In this paper the natural convection heat transfer performance of horizontal heat sink was studied by numerical simulation and experiment. The numerical simulation results show that there are some interesting features in the flow field of heat sink model. 1) Among the fins, the air vertically flows only through the fins in the symmetry center of heat sink while it horizontally flows through the fins in other area. 2) There is an air stagnation zone located at the fin root in the symmetry center of heat sink. These features both caused the decrease in heat transfer temperature difference and heat transfer area in fact. The natural convection heat transfer performance of heat sink is affected at last. In order to eliminate the air stagnation zone and change in the flow way of air, some holes were perforated at the fin root. These holes play its role. In this test, the heat transfer power of heat sink with seven holes has increased by 16.7% compared with the prototype.With the increase in the number of holes, the natural convection heat transfer power of heat sink also increases. But when the number of holes reaches to a value, the increase in the number of holes will not function properly.

Effect of Synthetic Jets Over Natural Convection Heat Sinks

2008 ◽  
Author(s):  
Mehmet Arik ◽  
Yogen Utturkar ◽  
Murat Ozmusul
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Operating Conditions ◽  
Heat Sinks ◽  
Junction Temperature ◽  
Allowable Limit

In moderate power electronics applications, the most preferred way of thermal management is natural convection to air with or without heat sinks. Though the use of heat sinks is fairly adequate for modest heat dissipation needs, it suffers from some serious performance limitations. Firstly, a large volume of the heat sink is required to keep the junction temperature at an allowable limit. This need arises because of the low convective film coefficients due to close spacing. In the present computational and experimental study, we propose a synthetic jet embedded heat sink to enhance the performance levels beyond two times within the same volume of a regular passive heat sink. Synthetic jets are meso-scale devices producing high velocity periodic jet streams at high velocities. As a result, by carefully positioning of these jets in the thermal real estate, the heat transfer over the surfaces can be dramatically augmented. This increase in the heat transfer rate is able to compensate for the loss of fin area happening due to the embedding of the jet within the heat sink volume, thus causing an overall increase in the heat dissipation. Heat transfer enhancements of 2.2 times over baseline natural convection cooled heat sinks are measured. Thermal resistances are compared for a range of jet operating conditions and found to be less than 0.9 K/W. Local temperatures obtained from experimental and computational agreed within ± 5%.

scholarly journals Comparative Analysis of Free Natural Convection Heat Transfer on Rectangular and Triangular Fins with and without Perforation

2018 ◽  
Vol 3 (5) ◽  
pp. 60
Author(s):  
Ogie Nosa Andrew ◽  
Joel Oluwayomi Oyejide
Keyword(s):  
Heat Transfer ◽  
Comparative Analysis ◽  
Natural Convection ◽  
Heat Dissipation ◽  
Nuclear Reactors ◽  
Research Work ◽  
Temperature Drop ◽  
Convection Heat Transfer ◽  
Engineering Application ◽  
Cylindrical Pipe

The importance of heat transfer by free natural convection can be found in many engineering application such as energy transfer in buildings, solar collectors, nuclear reactors and electronic packaging.  In this research work, we carried out the investigation and comparative analysis of heat transfer by natural convection on rectangular and triangular fins with and without circular perforation. A total of six (6) specimens were used.  Other materials that were used in this research work include four digital thermometers, one heating element, four thermocouple K-type and a power source.   The fins used in this research work were welded to a cylindrical pipe which served as the heat sink. The heat supplied was maintained at 2500C and the temperature drop through the fin was recorded for duration of 30minutes with intervals of 5minutes. It was observed that the temperature dropped more rapidly with the triangular fins than the rectangular fin. Also, the rate of heat dissipation increase with a corresponding increase in the number of perforation.

scholarly journals The Effect of Circular Perforation on a V-Corrugated Fin Performance under Natural Convection

2018 ◽  
Vol 24 (7) ◽  
pp. 19
Author(s):  
Maha Ali Hussein
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Heat Transfer Coefficient ◽  
Steady State ◽  
Natural Convection ◽  
Transfer Coefficient ◽  
Flat Plate ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Past Research

An experimental investigation has been made to study the influence of using v-corrugated aluminum fin on heat transfer coefficient and heat dissipation in a heat sink. The geometry of fin is changed to investigate their performance. 27 circular perforations with 1 cm diameter were made. The holes designed into two ways, inline arrangement and staggered in the corrugated edges arrangement. The experiments were done in enclosure space under natural convection. Three different voltages supplied to the heat sink to study their effects on the fins performance. All the studied cases are compared with v-corrugated smooth solid fin. Each experiment was repeated two times to reduce the error and the data recorded after reaching the steady state conditions. The results showed that the v-corrugated fin dissipate heat twice and triple times than flat plate mentioned in past research with the same dimension. Also, the inline perforated fin gave higher enhancement percentage than solid one by 15, 32 and 36% for 110, 150 and 200 V voltages supplied. Finally, the staggered perforation arrangement gave the higher enhancement percentage with 22, 42 and 45% for the same voltages supply.  

Natural Convection Heat Transfer With Horizontal Rectangular Fin Array Using Straight Knurling Patterns on Fins: An Experimental Study

2018 ◽  
Author(s):  
R. C. Chikurde ◽  
B. S. Kothavale ◽  
N. K. Sane
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Natural Convection ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Convection Heat Transfer ◽  
Flow Characteristics ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Heat Transfer Augmentation

Natural Convection heat transfer from horizontal rectangular fin array with various knurling patterns is studied experimentally to find the effect of varying surface roughness on the heat transfer rate. The experimental parametric study is performed to investigate the effect of knurl produced surface roughness of fin on heat transfer rate. The parameters like knurling height from base, knurling depth and fin spacing might affect the flow characteristics and hence it is investigated to find the effect on heat transfer coefficient. The knurling is usually accomplished using one or more very hard rollers that contain the reverse of the pattern to be imposed. The result of this study shows that there are some important geometric factors related to knurling affecting the design of fin arrays and also heat transfer augmentation of natural convection heat transfer is observed.

Enhanced Heat Transfer in Radial Heat Sinks for LED Lamps

2018 ◽  
Author(s):  
Fernando Cano-Banda ◽  
Ana Gallardo-Gutierrez ◽  
Jesus Garcia-Gonzalez ◽  
Abel Hernandez-Guerrero ◽  
Luis Luviano-Ortiz
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Heat Sinks ◽  
Output Analysis ◽  
Maximum Heat ◽  
Maximum Heat Transfer ◽  
Longitudinal Orientation ◽  
Radial Heat

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.

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