• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.8
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• pp.676-682
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• 2002

This paper has been made to investigate the thermal performance characteristics for the several types of heat sinks such as extruded heat sink, aluminum foam heat sink, layered heat sink. The various types heat sinks are prepared and tested for natural convection as well as forced convection. The experimental results for natural convection are compared to those for three types of heat sink so that the appropriate heat sink can be designed or chosen according to the heating conditions. The overall heat transfer performances for layered heat sink, extruded heat sink and aluminum foam heat sink are almost comparable to those under natural convection and forced convection. The forced convection of layered heat sink become 1.2 times as high as those of extruded heat sink, and the forced convection of extruded heat sink become 1.2 times as high as those of aluminum foam heat sink. This study shows that bar height, bar distance and number of bar for layered heat sink are important parameters, which have a serious influence on thermal performance for layered heat sinks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.523-528
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• 2013

In this experiment, we investigated the performance of two types of heat sink, swaged- and extruded-type, used in the inverter of industrial electricity generator. The swaged-type heat sink has 62 fins, and the extruded-type has 38 fins having the same dimension as that of the swaged-type. But the extruded-type heat sink maintains the same heat transfer area by the laterally waved surface which has 1 mm in radius. As a result, the swaged- and extruded-type heat sinks released 70.7% and 63.8% of the heat incoming to the heat sink, respectively. The other incoming heat were naturally convected and radiated to the ambient. In spite of 40% decrease in number of fins, the heat release performance of the extruded-type heat sink was lowered only 6.9% than that of the swaged-type. We believe that, this shows the increment of effective heat transfer area by the laterally waved surface of fins and the better heat transfer property of the extruded-type heat sink.

• Korean Journal of Materials Research
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• v.14 no.12
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• pp.870-875
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• 2004

Heat flow characteristics in the newly developed Wave Heat Sink were analyzed under natural and forced convections by Icepak program using the finite volume method. Temperature distribution and thermal resistance of Wave Heat Sink with/without air vent hole on the top of fin were compared with those of a commercial Al extruded heat sink(Intel Heat Sink). Under the natural convection, the maximum temperature was $45.1^{\circ}C$ in the air vent hole typed Wave Heat Sink, which was superior to that of Intel Heat Sink. The thermal resistance was $2.51^{\circ}C/W$ in the air vent hole typed Wave Heat Sink, and it changed to $2.65^{\circ}C/W\;and\;2.16^{\circ}C/W$ with changes of gravity direction and fin height, respectively. Under the forced convection, the maximum temperature became lower than that under the natural convection. In addition, the thermal resistance lowered in the air vent hole typed Wave Heat Sink with higher fin height and it decreased with increasing the air flux.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.3 no.2
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• pp.147-156
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• 1999

A numerical simulation has been carried out for the performance characterization of heat sinks in electronic equipment. Heat transfer characteristics have been analyzed for various design parameters including the shape of heat sink, thickness of fin base and fin pitches. A commercial program called Flotherm has been employed for the numerical calculation. Optimal design of the heat sink has been persued which is closely related with the reduction of heat resistance involved in conduction and convection of heat.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4749-4755
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• 2014

In this study, to maximize the heat release from the heat generating environment, such as a high-capacity inverter, the heat release performance of the extruded-type heat sinks with the variation of the base thickness were investigated using the experimental and numerical methods. The base thickness was varied from 5 to 14 mm. The heat release was characterized by the amount of heat released through the heat sink, the surface temperature of heat sink base between the heat sources, and temperature of heat sources. The surface temperatures between heat sources and the amounts of heat release were improved more as the base thickness was decreased. In contrast, the temperatures of the heat sources decreased with increasing base thickness. Based on the case study of these heat sinks, it is believed that a heat sink with a 9.5mm-thick base was optimized for the heat release.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.2
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• pp.119-126
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• 2016

In this study we investigated the effects of symmetrically arranged heat sources on the heat release performances of extruded-type heat sinks through experiments and thermal fluid simulations. Also, based on the results we suggested a high-efficiency and cost-effective heat sink for a solar inverter cooling system. In this parametric study, the temperatures between heaters on the base plate and the heat release rates were investigated with respect to the arrangements of heat sources and amounts of heat input. Based on the results we believe that the use of both sides of the heat sink is the preferred method for releasing the heat from the heat source to the ambient environment rather than the use of a single side of the heat sink. Also from the results, it is believed that the symmetric arrangement of the heat sources is recommended to achieve a higher rate of heat transfer. From the results of the thermal fluid simulation, it was possible to confirm the qualitative agreement with the experimental results. Finally, quantitative comparison with respect to mass flow rates, heat inputs, and arrangements of the heat source was also performed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.10
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• pp.933-940
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• 2013

In this study, we evaluated the heat release performance of two extruded-type and two swaged-type heat sinks used in an inverter for solar power generation. The number of fins and heat transfer areas of the two swaged-type heat sinks, namely S-62 and S-98, are 62 and 98 and $2.8m^2$ and $5.3m^2$, respectively. Those for the two extruded-type heat sinks, namely, E-38 and E-47, are 38 and 47 and $1.8m^2$ and $1.9m^2$, respectively. The heat release fractions of S-62 and S-98 were measured as 82.7 % and 86.3 %, respectively. Those of E-38 and E47 were measured to be 79.6 % and 81.6 %, respectively. In this experiment, despite the mass flow rates of air entering the heat sinks being almost the same, the heat release fractions increased with heat transfer area. Furthermore, despite S-62's heat transfer area being 47.4 % higher than that of E-47, its heat release fraction was higher by only 1.3 %. We believe that this indicates the better heat transfer property of the extruded-type heat sink. S-98's heat release is only 4.4 % higher than that of S-62, but its heat transfer area is 89.3 % higher; this suggests that its heat transfer area need to be optimized.

• Transactions of Materials Processing
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• v.13 no.5
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• pp.422-428
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• 2004

At present, the design of extrusion dies and operation in extrusion companies are primarily based on trial and error. The experience of the die designer, the press operator and the die corrector determine the performance of the extrusion die and the efficiency of the process. In order to produce defect-free products of desirable quality in terms of strength, surface quality and geometrical dimensions, it is important to obtain more knowledge of the processes that occur during extrusion. Recently, to reduce the costs of designing and manufacturing of extrusion dies, and to ensure the quality of the extruded products, numerical simulation for extrusion processes such as FEM (finite element method) is applied increasingly and becomes a very important tool for the design and development of new products. However, most of the studies about FE simulation have been accomplished for simple geometry and low extrusion ratio in the filed of steady metal flow conditions. The extruded products of AI alloy in industrial practice involve complicated sectional geometry. This study was designed to reduce the time of die design and manufacturing in the extrusion process using FEM simulation. FEM simulations of extrusion process were performed in non-steady states conditions by changing weld plate included in extrusion die set. Product which was employed in this study is heat sink that has been used in the parts of heat exchanger of electric circuits. It is generally applied for aluminum or its alloys due to heat efficiency and easy production of complicated shapes, and manufactured by extrusion process. The simulated results showed that weld plate shape in extrusion dies influences meta] flow and dimensional accuracy of products.