• Title/Summary/Keyword: Oscillating Capillary Tube Heat Pipe

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Flow Visualization of Oscillation Characteristics of Liquid and Vapor Flow in the Oscillating Capillary Tube Heat Pipe

  • Kim, Jong-Soo;Kim, Ju-Won;Jung, Hyun-Seok
    • Journal of Mechanical Science and Technology
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    • v.17 no.10
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    • pp.1507-1519
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    • 2003
  • The two-phase flow patterns for both non-loop and loop type oscillating capillary tube heat pipes (OCHPs) were presented in this study. The detailed flow patterns were recorded by a high-speed digital camera for each experimental condition to understand exactly the operation mechanism of the OCHP. The design and operation conditions of the OCHP such as turn number, working fluid, and heat flux were varied. The experimental results showed that the representative flow pattern in the evaporating section of the OCHP was the oscillation of liquid slugs and vapor plugs based on the generation and growth of bubbles by nucleate boiling. As the oscillation of liquid slugs and vapor plugs was very speedy, the flow pattern changed from the capillary slug flow to a pseudo slug flow near the annular flow. The flow of short vapor-liquid slug-train units was the flow pattern in the adiabatic section. In the condensing section, it was the oscillation of liquid slugs and vapor plugs and the circulation of working fluid. The oscillation flow in the loop type OCHP was more active than that in the non-loop type OCHP due to the circulation of working fluid in the OCHP. When the turn number of the OCHP was increased, the oscillation and circulation of working fluid was more active as well as forming the oscillation wave of long liquid slugs and vapor plugs in the OCHP. The oscillation flow of R-142b as the working fluid was more active than that of ethanol and the high efficiency of the heat transfer performance of R -142b was achieved.

Development of Micro Cooling System for Telecommunication System using Oscillating Heat Pipe (진동 세관형 히트파이프를 이용한 통신 기기용 마이크로 냉각시스템의 개발)

  • Ha, Soo-Jung;Bae, Nae-Soo;Park, Chul-Min;Kim, Jung-Soo
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1499-1505
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    • 2003
  • Rapid development of electronic technology requires small size, high density packaging and high power of electronic devices. So, in this paper, characteristics on oscillating heat pipe according to operating conditions(environment temperature, charging ratio of working fluid, inclination) based on experimental study was investigated. From the experimental results, $25^{\circ}C$environment temperature), R-141b(working fluid)40%(charging ratio) was best performace at others of inclination angle and The top heating mode of OCHP performed 80% efficiency of the bottom heating mode.

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An Experimental Study on the Hydration Heat Control of Mass Concrete Using Heat Pipe (히트파이프를 이용한 매스콘크리트의 수화열 제어에 관한 실험 연구)

  • BaeK, Dong-Il
    • Journal of Ocean Engineering and Technology
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    • v.21 no.6
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    • pp.81-86
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    • 2007
  • In order to eliminate the hydration heat of mass concrete, this paper reports the results of hydration heat control in mass concrete using the OCHP (Oscillating capillary tube heat pipe). In the summarized results of the mock up experiments, distributing the heat pipe at 300 mm intervals based on the center of the test specimen was the most effective. A 200 mm turn interval for the heat pipe was measured to be the most appropriate, taking into account the reinforcement placing at the actual site. Therefore, when the hydration heat control method using the heat pipe developed in this study is applied, not only canconstruction efficiency & a reduction in the necessary construction time be expected, but so can outstanding economical effects.

An Experimental Study on the Dispersion Effect of Hydration Heat in the Mass Concrete Using OCHP (OCHP를 이용한 매스콘크리트 수화열 분산효과에 관한 실험적 연구)

  • Kim, Myung-Sik;Baek, Dong-Il;Kim, Kang-Min;Yum, Chi-Sun;Bae, Won-Mahn
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05b
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    • pp.437-440
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    • 2006
  • In process of the mass concrete structure, the heat of hydration may cause serious thermal cracking. In order to eliminate hydration heat of mass concrete, this paper results of hydration heat control of mass concrete using the Oscillating Capillary tube Heat Pipe(OCHP). There were the several molds which shows a difference as compared with each other. One was not equipped with OCHP. Other were laid with OCHP, and the other were laid in 100cm, and exposed out 50cm. All of them were cooled with natural air convection. The OCHP was composed of copper pipe(outer diameter : 4mm, inner diameter : 2.8mm) and heat type was non-looped type. The working fluid was R-22 and its charging ratio was 40% by volume. The core of the concrete temperature was approximately $53^{\circ}C$ without OCHP. But the concrete temperature with OCHP was reduced its difference in temperature with the outdoor temperature to $12{\sim}15^{\circ}C$. Finally we saw the index figure of the thermal crack of the structures were varied from 0.6 to 1.6.

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Performance Characteristics of a Loop Thermosyphon for Heat Source Cooling (열원 냉각용 루프 써모사이폰의 작동 특성)

  • Choi, Du-Sung;Song, Tae-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.12
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    • pp.1475-1483
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    • 2004
  • Loop thermosyphon(LTS) has many good characteristics such as low thermal resistance, no power consumption, noiseless operation and small size. To investigate the overall performance of LTS, we have performed various experiments varying three parameters: input power of the heater, working fluid(water, ethanol, FC3283) and filling ratio of the working fluid. At a combination of these parameters, temperature measurements are made at many locations of the LTS. The temperature difference between the evaporator and the condenser is used to obtain the thermal resistance. In addition, flow visualization using a high speed camera is carried out. The thermal resistance is not constant. It is lower at higher input power, which is one of the distinct merits of LTS. Flow instabilities are frequently observed when changing the working fluid, the input power and the filling ratio. The results show that the LTS can be readily put into practical use. Future practical application in electronic cooling is recommended.