• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1651-1656
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• 2003

The present study has been conducted to analytically investigate the thermal control performance of variable conductance heat pipe(YCHP) with axial grooves. The condenser port of the YCHP is occupied by a inert gas in which the concentration of gas is varied with the operation temperature and the heat transport capacity is thus varied with the operating temperature due to the variation of inert gas concentration. In this study, numerical evaluation for the thermal control of the YCHP with axial grooves is made from the 1st order diffusion model that considers the diffusive expansion of inert gas by concentration gradient. Ammonia is used as a working fluid and Nitrogen as a control gas in the Aluminum tube. As a result, the thermal performance of YCHP based on diffusion model has been compared with that of YCHP from flat front model. Additionally, it is found that the concentration of inert gas is distributed in the condenser region of YCHP with axial grooves.

• 설비공학논문집
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• 제15권1호
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• pp.1-8
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• 2003

An analytical and experimental study of the thermal performance of axial heat pipe with axial groove is conducted to determine the optimal mass of working fluid for the maximum heat transport capacity of heat pipe with axial grooves. Generally, the mass of working fluid has been fully charged by considering only a geometrical shape of axial grooves embedded in a heat pipe. When the heat pipe is operated in a steady state, the meniscus re-cession phenomena of working fluid is occurred in the evaporator region. In this work, the optimal mass of working fluid was obtained from the axial variation of capillary pressure, the radius of curvature and wetting angle of meniscus of liquid-vapor interface. Experimental results were also obtained by varying the mass of working fluid within a heat pipe, and presented for the maximum heat transport capacity corresponding to the operating temperature and the elevation of heat pipe. Finally, the analytical results of the optimal mass of working fluid were compared with those of the experimental mass of working fluid.

• 태양에너지
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• 제11권1호
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• pp.78-86
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• 1991

내부에 삼각형 핀을 갖는 회전형 히트파이프의 작동유체로 물-에탈올 2성분 유체를 사용하였을때 Nusselt의 막응축이론을 기초로 하여 핀 및 그루브의 전열특성을 유한요소법에 의한 수치해석을 하였으며 또한 실험을 행하여 비교하였다. 히트파이프의 회전수가 증가할수록, 내부 증기압이 높을수록 전열량은 완만하게 증가하지만 에탄올 농도가 커 질수록 전열량은 감소하였다. 그리고 순수 에탄올만을 작동유체로 하는 경우는 증류수만을 작동유체로 하는 경우의 전열량의 $0.75{\sim}0.85$정도로 나타났다. 또한 에탄올 농도가 0. 2전후에서 전열효과 및 작동온도 범위 등이 가장 유리하게 나타났다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.333-338
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• 2006

This study is a research on Dual Bore heat pipe to investigate the ability of heat transport ability, heat resistance and difference of heat transport ability according to the type of heat pipes. As the result of this research, we got several conclusions. Each pipe of Dual Bore in one section has a similar heat transfer capability. In the range between $-20^{\circ}C$ and $60^{\circ}C$ the heat transfer capability is double than single bore which was analyzed by menas of GAP program. Heat resistance is below $0.05^{\circ}C$/W at every point, and it tells aluminum-ammonia heat pipes are proper for satellite.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.30.2-30.2
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• 2005

• 설비공학논문집
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• 제13권5호
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• pp.363-363
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• 2001

• 설비공학논문집
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• 제14권8호
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• pp.664-670
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• 2002

A heat sink (HS) system using heat pipes for electronics systems was studied. The experimental results indicate that a cooling capacity of up to 150w at an overall temperature difference of $50^{\circ}C$ can be attainable. The heat sink design program also showed that a computer simulation can predict the most of the parameters involved. To do so, however, the interior temperature distribution had to be verified by experimental results. The current simulation results were close to the experimental results in acceptable range. The simulation study showed that the design program can be a good tool to predict the effects of various parameters involved in the optimum design of the heat sink.

• 에너지공학
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• 제12권1호
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• pp.17-22
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• 2003

본 연구는 소형 CPL히트파이프의 제작 및 작동 특성에 대한 기초 지식을 얻기 위하여 수행되었다. CPL 히트파이프는 중력장 내에서 먼 거리까지 효과적으로 열을 이송할 수 있는 능력을 가지고 있다. 컴퓨터 칩에서 발생되는 열을 냉각하기 위하여 원판형 증발부로 구성된 소형 CPL을 설계 및 제작하여 그 작동 성능을 실험하였다. 두께 3mm, 직경 50mm의 원판형 청동 분발 소결 (equation omitted)를 사용하여 작동유체를 순환하기 위한 압력 구배를 얻을 수 있었으며 작동유체는 에탄올을 사용하였다. 실험은 응축부의 주위온도를 13$^{\circ}C$로 고정시킨 후 각각 다른 열부하에서의 CPL 작동 상태를 확인해 보았다.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 추계학술발표논문집 2부
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• pp.941-943
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• 2010

근래 LED 조명기기 연구는 출력이 낮은 조명기기에서 고출력 전원을 이용한 고휘도 제품 개발로 바뀌는 추세이다. 고출력을 이용할 경우 단순히 히트싱크 형상, PCB 배치 및 물성 변경을 통한 방열문제 해결 방법으로는 LED 조명기기의 수명감소 문제를 해결하는데 한계가 있다. 따라서 방열능력을 더욱 향상시킬 수 있는 히트파이프(heat pipe)의 필요성이 대두되었다. 본 연구에서는 히트파이프를 이용해 고출력 LED 조명기기 개발을 위한 연구를 수행하였다.

• 대한기계학회논문집B
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• 제25권12호
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• pp.1711-1720
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• 2001

In this study, the heat transfer characteristics of a U-shape heat pipes were investigated. Heat is supplied to the U heat pipe through its middle zone(evaporator), and is released to the environment through its both arms(condensers). Both heat transfer coefficients and heat transport limitations were measured and compared with correlations previously developed for straight type heat pipes. Special concerns were focused to the cases, when each of condensers were submitted to a different cooling conditions, relatively. As a result. the heat transfer limitation of a U-shape heat pipe was found out to be 10∼15% less than the value for a straight heat pipe with an equivalent size.