• 한국기계가공학회지
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• 제10권6호
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• pp.122-127
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• 2011

In this study, it was compared collecting performance according to contact types between heatpipe and manifold of vacuum tube type solar collector. Between two types, direct contact type is better in collecting performance. On the other hand, Indirect type have advantage in maintenance. In the result of numerical analysis, As the temperature of heatpipe and flow rate of working fluid increased, difference of outlet mean temperature of two types became large. Also, it could be confirmed, as contact resistance between heatpipe and copper tube in indirect type increased, the difference increased too. Useful data in selection and design in vacuum tube type solar collector were proposed by the results of numerical analysis.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2110-2115
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• 2008

In this study, We disigned and manufactured the Hot Chuck which can be operated until $120^{\circ}C$. Its shape is circular, wide is 300mm and depth is 15mm. Two types working fluid was used as working fluid(distilled water, 0.1%-$TiO_2$ nanofluid). The experimental results were compared to each working fluid. The effect of various working fluid, charging volume ratio was investigated. Also we investigated heat transfer rate against each working fluid. By using nanofluid, heat transfer rate can be enhanced and the wick structure can be constructed automatically on smooth surface. The experiment of 40% charged 0.1%-$TiO_2$ nanofluid showed the best performance of thermal accuracy and uniformity. To improve performance of Hot Chuck, more study is needed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1646-1651
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• 2004

This paper has been carried out to find the thermal efficiency and operating characteristics of heatpipe type solar collector using a glass concentric evacuated tube(CETC) during summer. In an experiment the flow rate of water in collector are 1.5l/min. Collector efficiency is $50{\sim}60%$ during time. The solar radiation appeared in a clear day is efficiency high. Efficiency curve fitted first order polynomial show that $F_{R}$$({\tau}{\alpha})$ and $F_{R}U_{L}$=1.316 is 0.601 and 1.316 respectively.

• 한국결정학회지
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• 제4권1호
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• pp.42-48
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• 1993

K6P4Ol3 응제를 사용하여 TSSG법에 의해 KTP(K Tiop04) 단결정을 성장시켰다. 가열로의 내부에 heatpipe와 복사방열판을 설치하여 도가니 내의 온도 안정성 및 균일도를 향상시켰다. 크고 양질의 단결정을 얻기 위한 목적으로 조업온도 구간,초기 냉각속도, 강제교반, 융제의 재사용과 같은 몇 가지 조업변수들에 따른 영향을 비교 고찰하였다. 본 융제의 조건하에서(0.6g KTP/lg flux), 초기 냉각속도가 0.1℃/hr 이하까지 느릴수록, 적절한 결정 회전이 수반될수록 양질의 단결정성장에 유리하였다. 최대 44 × 39 ×17체 크기의 KTP단결정을 얻을 수 있었으며, 단순가공 상태하에서도 21.3% SHG 변환효율을 나타내었다.

• Journal of Advanced Marine Engineering and Technology
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• 제29권8호
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• pp.862-869
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• 2005

A study on convective cooling characteristics has been done in the channels with heat pipes and associated Plane fins Analysis with FLUENT V5.0 lies its Purpose on the possible enhancement of heat transfer capability between an existing three in-line arrayed heatpipes and an extending four in-line arrayed heatpipes with increasing channel width. Numerical analysis is limited to the laminar flow in an isolated flow channel by employing cyclic boundary conditions for calculation purposes. Friction factors for three and four in-line arrayed heatpipes are compared with experimental results. In addition, temperature behavior at the plate fin for the three in-line arrayed heatpipes is compared with experiment. Friction factors and overall channel heat transfer coefficients (and/or Nusselt numbers) are presented as a function of Reynolds number. An increase of number of heatpipes and channel width reults in a decrease of the friction factor and doesn't not result in an increase of heat transfer performance. However. considering the 25$\%$ increase of heat load accompanies with maximum 8$^{\circ}C$ rise of average temperature of heat pipes, the four in-line array with the increase of channel width of heat pipe heat sink can be considered appropriate.

• 한국기계가공학회지
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• 제16권4호
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• pp.147-152
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• 2017

In the present study, we used a loop thermosyphon heat exchanger consisting of condensers with internal fins and external plate fins which are 480 mm wide, 68 mm long, and 1,000 mm high. The heat transfer pipes in the heat exchanger were 15 mm in diameter and 1,000 mm in length, and 98 heat transfer pipes were installed in the heat exchanger. According to the experimental results, as the spaces between the internal discontinuous pins decreased, the frequency of pressure drops increased and changes in temperature at the outlet of the condenser were shown to be a little smaller. Therefore, we can see that as the spaces between internal discontinuous pins decreased, the heat transfer performance increased. For the loop heat pipe heat exchanger consisting of a condenser with internal and plate fins, as the temperature of the air flowing into the condenser increased, the condensation heat transfer rate also increased, and as the condenser refrigerant inflow temperature increased, the condensation heat transfer rate increased as well.