• 설비공학논문집
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• 제12권3호
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• pp.227-234
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• 2000

An experimental study was performed for understanding the limiting power and heat transfer characteristics of an MHP having the diameter of 3 or 4 mm which could be applied to cooling of miniature electronic equipment such as the notebook PC CPU etc. The experimental parameters which are inclination, structure of the wick, the length of the condenser and the total heat pipe were considered. The MHP with a woven-wired wick has the advantages of the improvement in capillary limit, the effective attachment tightly toward wall and the convenience in construction of wick. Cooling performance of the present MHP was compared with that of MHP with grooved, fine fiber and sintered type wick which were applied by existing enterprises. With respect to the inclination of$ -5^{\circ}$ , an MHP having the diameter of 3 or 4 mm shows the limiting power of 6~14 W. Therefore, it is expected that the MHP of the present study has sufficient applicability of cooling of notebook PC of which the amount of heat generated is about 12 W.

• 한국추진공학회지
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• 제8권4호
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• pp.16-25
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• 2004

구리분말 소결윅 히트파이프의 열수송 한계를 예측하는 이론적 해석을 수행하였다. 히트파이프의 직경은 8 mm이고 물을 작동유체로 사용하였다. 입자의 직경을 대표적인 5 가지로 분류하여 각각의 유효 모세관 반경($r_c$) 기공률($\varepsilon$), 투파율(K)을 토대로 작동온도와 윅 두에 그리고 경사각에 따른 모세관압력과 열수송 한계, 열저항을 분석하였다. 소결윅의 모세관한계는 입자 직경이 크고 윅 두께가 증가하며 작동온도가 높을수록 증가했다 기공률과 모세관 반경이 증가할수록 열수송 한계가 높아졌으며, 윅 두께가 증가함에 따라 열저항이 크게 상승하였다.

• 한국지반공학회지:지반
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• 제11권4호
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• pp.13-24
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• 1995

5가지의 토질을 대상으로 하여 심지배수가 존재하는 경우와 그렇지 않은 경우에 있어서 진공압밀실험을 실시하여 진공압밀에서의 시간에 따른 침하량을 측정하였다. 이에 앞서 기초실험을 통하여 토질의 특성을 파악하고 아울러 일차원 압밀실험을 행하여 심지배수가 존재하지 않은 경우의 진공압밀이 진행되는 동안 기존의 압밀 실험이 토질의 거동을 예측할 수 있는지를 검토하여 보았다. 본 연구결과 기존의 일차원 압밀실험은 심지배수가 존재하지 않는 경우의 진공압밀 실험과정을 예측하는데 부적절하였으나 최종침하량은 적절하게 예측하였음이 밝혀졌다. 진공압밀의 실험결과에서는, 실트질토에 있어서 심지배수의 존재가 압밀의 속도에는 커다란 영향을 미쳤으나 최종 침하량은 심지배수의 존재에 상관없이 동일하였음이 밝혀졌으며 심지배수의 존재는 시료의 깊이에 대해 함수비와 밀도를 일정하게 한다는 것은 규명되었으나 점토질토에서의 심지배수의 존재는 압밀의 속도 뿐만 아니라 최종침하량도 증가시킴이 밝혀졌다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1052-1057
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• 2004

A small-scale loop heat pipe with polypropylene wick was fabricated and tested for its thermal performance. The container and tubing of the system was made of stainless steel and several working fluids were used to see the difference in performance including methanol, ethanol, acetone, R134a, and water. The heating area was 35 mm ${\times}$ 35 mm and there were nine axial grooves in the evaporator to provide a vapor passage. The pore size of the polypropylene wick inside the evaporator was varied from 0.5 m to 25 m. The size of condenser was 40 mm (W) ${\times}$ 50 mm (L) in which ten coolant paths were provided. The inner diameter of liquid and vapor transport lines were 2.0 mm and 4.0 mm, respectively and the length of which were 0.5 m. The PP wick LHP was operated with methanol, acetone, and ethanol normally. R134a was not compatible with PP wick and water was unsuitable within operating limit of $100^{\circ}C$. The minimum thermal load of 10 W (0.8 W/cm2) and maximum thermal load of 80 W (6.5 W/cm2) were achieved using methanol as working fluid with the condenser temperature of $20^{\circ}C$ with horizontal position.

• 대한수학회지
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• 제33권4호
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• pp.993-1008
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• 1996

The white noise analysis, initiated by Hida [3] in 1975, has been developed to an infinite dimensional distribution theory on Gaussian space $(E^*, \mu)$ as an infinite dimensional analogue of Schwartz distribution theory on Euclidean space with Legesgue measure. The mathematical framework of white noise analysis is the Gel'fand triple $(E) \subset (L^2) \subset (E)^*$ over $(E^*, \mu)$ where $\mu$ is the standard Gaussian measure associated with a Gel'fand triple $E \subset H \subset E^*$.

• International Journal of Air-Conditioning and Refrigeration
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• 제10권2호
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• pp.72-78
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• 2002

Woven wire wick is a very effective structure because of its easiness to insert inside of pipe for a miniature heat pipe. The present study was conducted to predict the porosity and the effective thermal conductivity of liquid-saturated woven wire wick. The porosity and the effective thermal conductivity of the evaporator region indicate different values from those of the condenser region due to the existence of non-flow region. The minimum value of the effective thermal conductivity indicates on condition of the $\theta$=$45^{Wcirc}$ and the values of the effective thermal conductivity increases symmetrically centering around the minimum value. The values of the effective thermal conductivity in the evaporator region at the angle of $45^{Wcirc}$ indicate about 60~80% higher than those in the condenser region for various combinations of copper, and stainless with water and ethanol.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.48-53
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• 2001

This experimental study is to research heat transfer characteristics in copper-water heat pipes with screen wick, the 150 and 200-mesh. Recent advances in the miniaturization and large capacity of electronic devices have had a major impact on the design of electronic equipment. As a result, a high-performance cooling system is needed. Experimental variables are inclination angle, number of layer and temperature of cooling water. The distilled water was used for the working fluid. At a inclination angle $6^{\circ}$, the 200-mesh screen wick 3-layer is shown the best heat transfer performance.

• 한국에너지공학회:학술대회논문집
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• 한국태양에너지학회, 한국에너지공학회 1993년도 춘계 공동학술발표회 초록집
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• pp.70-78
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• 1993

Heat pipes, applied to flat plate solar collectors, have a long and slender configuration with relatively low heat flux on the evaporator. Such a heat pipe has a tendency to build-up a liquid pool at the lower half of evaporator zone, and at this pool occurs such complicated phenomena of evaporation and fluid dynamics as superheat, sudden generation of bubble, its likely explosive growth process and flooding etc. In the present study, we tried to solve those problems by means of adjusting the two principle design parameters, liquid fill charge and wick length, using 4 heat pipes and 3 thermosyphons, with different values of parameter respectively. The corresponding results can be summarized as followings, - The thermal conductance of heat pipes was largely improved by el eliminating wick from adiabatic and condenser zone. - But on evaporator zone wick is inevitable to reduce behavior of the build -up of liquid pool , where arise diverse internal complex phenomena. - The liquid fill charge should have to be increased by 10∼20％ more than the quantity to saturate the wick.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2137-2143
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• 2008

This paper investigates the plate loop heat pipe system with an evaporator mounted with fin-wick structure to dissipate effectively the heat generated by the electronic components. The heat transfer formulation is modeled and predicted through thermal resistance analysis of the fin-wick structure in the evaporator. The experimental approach measures the thermal resistances and the operating characteristics. These results gathered in this investigation have been used to the objective of the information to improve the LHP system design so as to apply as the future cooling devices of the electronic components.

• 태양에너지
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• 제6권2호
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• pp.76-85
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• 1986

The study on the characteristics of heat transfer by various working fluid and wick structure is an important subject in order to design low temperature heat pipe. The purpose of this research was to study the heat transfer characteristics of heat pipe according to various working fluid and wick thickness by ADI method and experimental results. As the results the heat transfer by various working fluid could improve by good heat conductivity of fluid and small ratio t/k. The working fluid could be selected in close vicinity to boiling temperature among fluid properties the value of ratio little influenced heat transfer of heat pipe. In case of distilled water, the response of the effect in heat recovery was more rapidly showed than response of other working fluid. The maximum heat flux increased in proportion to the characteristics of working fluid but the pore and wick permeability among wick characteristic was little effect in the wetting state.