• 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.1
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• pp.27-33
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• 2013

To ensure proper functioning of electrical and mechanical systems, cooling devices are of great importance. A heat sink is the most common cooling device used in many industries such as the semiconductor, electronic instrument, LED lighting, and automotive industries. To design an optimal heat sink, the required surface area for heat radiation should be calculated based on an accurate expectation of the heat flow rate in the target environment. In this study, the convective heat flow characteristics were numerically investigated for a vertically installed typical heat sink and a horizontally installed one in free convection using ANSYS CFX. Comparative experiments were carried out to reveal the quantitative effect of the installation direction on the cooling performance. Moreover, the result was analyzed using the dimensionless correlation with the Nusselt number and Rayleigh number and compared with well-known theories. Finally, it was observed that the cooling performance of the vertically installed heat sink is approximately 10~15% better than that of the one in natural convection.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.2
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• pp.179-184
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• 2010

This experimental study investigated the effect of tip clearance and bypass flow on the cooling performance of a straight fin heat sink. Both the horizontal and vertical directions of the bypass flow were studied by using a mass flow controller and test sections. The thermal resistance of a heat sink was obtained to elucidate the response of the cooling performance to tip clearance and bypass flow. The thermal resistance of a straight fin heat sink gradually increases with increasing tip clearance. A flow guide unit was employed to reduce the bypass flow. An optimal distance from the leading edge of the heat sink to the flow guide unit was found for the fixed volume flow rate. The contribution of the flow guide unit to the thermal performance of a heat sink increases with increasing volume flow rate.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.556-557
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• 2010

본 논문은 하이브리드 자동차의 구동모터용 인버터에 적용되는 수랭 히트싱크의 설계 타당을 수치해석을 통해 검증하는 방법을 제시한다. 전력변환장치의 손실 계산, 발열체 모델링, 히트싱크 형상 모델링, 수랭 조건 입력, 히트싱크상의 열적 분포 해석, 유체 거동 시뮬레이션의 과정을 거치며, 본 논문에서는 650Vdc, 150kW급의 시리즈 하이브리드 차량의 구동 모터용 인버터를 예로 그 과정을 설명하고자한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.4
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• pp.343-350
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• 2015

The natural convection heatsink is the most commonly used cooling device, especially for high-power LED lights, because of its reliability and low long-term cost. High power LED lights are generally used in an inclined configuration for street lamps and security lamps. However, it was difficult to estimate the thermal performance of an inclined heatsink, because the results from previous studies are not applicable to the inclined configuration. In this study, we measured the thermal performance of an inclined cylindrical heatsink with plate fins. Various fin numbers, fin heights, base temperatures, and inclination angles ($30^{\circ}$ and $60^{\circ}$) were examined. Based on the experimental results, the Nusselt number correlation is presented. This correlation is applicable when the Rayleigh number, ratio of the fin height to cylinder diameter, and fin number are in the ranges 100,000-600,000, 1/6-1/2, and 9-72, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.6
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• pp.571-578
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• 2012

In this paper, an experimental investigation is performed to estimate the thermal performance of a natural convective heat sink with plate fins subject to the uniform wall temperature condition. Extensive experiments are performed with various input powers, fin spacings, and heights of the natural convective heat sinks with plate fins. In particular, the effect of the inclination angle on the thermal performance of the heat sink is studied. In order to validate the experimental data, the experimental results are compared with results from previous studies. Based on the experimental results, the appropriate ranges of the previous correlations between the input power, the fin spacing, the fin height, and the inclination angle for the natural convective heat sink with plate fins are evaluated.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.539-541
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• 2006

전력 반도체의 방열 특성은 수명 및 소손과 관계가 있다. 전력 반도체 자체의 열전달 특성 및 전력 반도체가 취부 되는 방열판의 전도, 대류, 방사의 열전달 특성을 고찰하기 위하여 본 논문에서는 실시간으로 방열판의 온도를 관측하여 전력 반도체의 손실을 확인하였고, 프로파일별 히트 싱크 온도 상승 측정 평균 전류와 전류 프로파일과 의 상관 관계를 분석 하여 방열판 최적화 및 히트 싱크 온도 관측 시 히트 싱크의 모델을 제시하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.1
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• pp.35-39
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• 2013

This paper reports numerical study results with respect to the thermal behavior of a natural convection cooled hybrid fin heat sink (HFH). The HFH consists of hybrid fins, hollow pin fins integrated with plate fins. The thermal performance of the HFH was numerically investigated by employing a commercial CFD software package and compared with that of the pin fin heat sink (PFH). Numerical study has found that array-based and mass-based heat transfer coefficients of the HFH are 12% and 37% greater than those of the PFH, respectively. Extended surface area and lighter weight may explain the better thermal performance of the HFH than the PFH.

• The Magazine for Energy Service Companies
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• s.62
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• pp.58-65
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• 2010

최근 가정용 컴퓨터와 노트북 등의 중앙처리장치(CPU) 속도가 급격히 빨라지고 있다. 더욱이 화석 에너지 고갈 위기에 따라 제품의 발열량은 급속도로 늘어날 전망이라는 관측이 나왔다. 때문에 에너지절약에 대한 해결이 동반된 연구가 이뤄져야 한다는 목소리가 커지고 있다. 이러한 문제를 해결하기 위해 발열원에 히트싱크를 직접 부착하는 강제대류 방식에 대한 연구가 진행되고 있고, 최근 들어 열전소자를 이용한 냉각방식과 히트파이프를 이용한 방식도 대두되고 있다. 그 중 열저항 특성 연구에 집중했던 기존 방식에서 벗어나 Pulsating Heat Pipe(PHP)를 열확산기로 적용시킨 연구방식을 소개한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.4
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• pp.385-390
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• 2012

A radial heat sink, adopted to LED(light emitting diode) downlight, was optimized. Discrete transfer radiation model (DTRM) was used to calculate radiation heat transfer, and numerical model was verified with experimental results. The effects of number of fin, long fin length and middle fin length on overall thermal resistance and radiation heat transfer were analyzed. As the emissivity increased, thermal resistance decreased due to the increment of radiation heat transfer. The radial heat sink was optimized and optimum number of long fins is 19~28, optimum length of long fin is about half of radius of heat fink and optimum fin ratio is 0.4~0.7.