• Title/Summary/Keyword: Heatpipe

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Comparison of Collecting Performance according to Contact Types of Heatpipe in Vacuum Tube Type Solar Collector (진공관형 집열기 히트파이프 접촉방식에 따른 집열성능 비교)

  • Yun, Ji-Hun;Jeong, In-Guk;Yi, Chung-Seob;Chung, Kyung-Teak;Suh, Jeong-Se
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.6
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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.

Thermal characteristics of Nanofluidic Heatpipe Hot Chuck (나노유체를 이용한 히트파이프 핫척의 열적 특성)

  • Lim, Taek-Kyu;Rhi, Seok-Ho;Kim, Dae-Hyun;Lee, Chung-Gu
    • Proceedings of the KSME Conference
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    • 2008.11b
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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.

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An Experimental Study for Apply Solar System on Thermal Performance of Heat Pipe Type Solar Collector using a Glass Concentric Evacuated Tube in a Summer (하절기 태양열 시스템 적용을 위한 이중진공관 히트파이프형 집열기 열성능의 실험적 연구)

  • Kang, C.H.;Bae, C.H.;Hong, J.K.;Suh, J.S.
    • Proceedings of the KSME Conference
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    • 2004.11a
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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.

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An Experimental Study of KTP Crystal Growing by TSSG Method (TSSG 법에 의한 KTP 단결정 성장의 실험적 연구)

  • 김형천;윤경구
    • Korean Journal of Crystallography
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    • v.4 no.1
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    • pp.42-48
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    • 1993
  • KTP(KTiOPO4) single crystals were grown by the TSSG(top seeded solution growth) method using the Ksp401s flux. A heat-pipe based growing furnace was used, and the temperature stability and the homogenity of the growing solution in the platinum crucible were within the level of It 0.5℃ and ±0.9℃, respectively. The effects of some operating variables such as operating temperature range, initial cooling rate, forced stirring, reuse of the flux were investigated. As the initial cooling rate was decreased to the degree of 0.1℃/hr and some proper stirring effect by the crystal rotation was introduced to the present experimental condition, bigger and better crystals without inclusion grew. A single crystal with the maximum sixte of 44 ×39 ×17mm3 was obtained and showed the SHG conversion efficiency of 21.39) even without the anti-refilection coating.

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A Numerical Analysis of Convective Heat Transfer in Air Flow Channels of a Plate Fin-tube Matrix for Heat Pipe Heat Sinks (히트파이프 히트싱크에서 평판 휜-관으로 구성된 공기유동 냉각채널의 대류 열전달 특성에 관한 수치해석)

  • Kim Sung-Hoon;Shin Hyun-Myung;Kim Chul-Ju
    • Journal of Advanced Marine Engineering and Technology
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    • v.29 no.8
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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.

A Study on the Condensation Heat Transfer Characteristics of a Loop Heat Pipe Heat Exchanger for High Speed Rotary Shaft Cooling (고속 회전축 냉각용 루우프 히트파이프 열교환기의 응축열전달 특성에 관한 연구)

  • Cho, Dong-Hyun;Lee, Jong-Sun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.4
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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.