• Title/Summary/Keyword: 루프히트파이프

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Analytical Modeling of a Loop Heat Pipe with a Flat Evaporator by Applying Thin-Film Theory (평판형 증발부를 갖는 루프히트파이프에 대해 박막이론을 적용한 해석적 모델링)

  • Jung, Eui-Guk;Boo, Joon-Hong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.12
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    • pp.1079-1085
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    • 2010
  • A steady-state analytical model was presented for a loop heat pipe (LHP) with an evaporator that has a flat geometry. On the basis of a series of reviews of the relevant literature, a sequence of calculations was proposed to predict the temperatures and pressures at each important part of the LHP: the evaporator, liquid reservoir (compensation chamber), liquid line, vapor line, and condenser. The analysis of the evaporator, which is the only part in the LHP that has a capillary structure, was emphasized. Thin-film theory is applied to account for the pressure and temperature in the region adjacent to the liquid-vapor interface in the evaporator. The present study introduced a unique method to estimate the liquid temperature at the interface. Relative freedom was assumed in the configuration of a condenser with a simplified liquid-vapor interface. Our steady-state model was validated by experimental results available in the literature. The relative error was within 3% on the absolute temperature scale, and reasonable agreement was obtained.

Theoretical Analysis of the Pressure Drop in Loop Heat Pipe by Sintered Porous Wick Structure (다공성소결윅구조에 따른 루프 히트파이프에서 압력손실의 이론적 분석)

  • Lee, K.W.;Lee, W.H.;Park, K.H.;Lee, K.J.;Chun, W.P.;Ihn, H.M.
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1225-1230
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    • 2004
  • In this paper, the pressure drops were investigated according to the sintered porous wick structure in loop heat pipe(LHP) by theoretical analysis. LHP has the wick only in evaporator for the circulation of working fluid, so utilizes porous wick structure which pore diameter is very small for large capillary force. This paper investigates the effects of different parameters on the pressure drops of the LHP such as particle diameter of sintered porous wick, wick porosity, vapor line diameter, thickness of wick and heating capacity. Working fluid is water and the material of sintered porous wick is copper. According to the these different parameters, capillary pressure, pressure drop in wick were analized by theoretical design method of LHP.

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A Study on the Miniature Loop Heat Pipe with Non-inverted Meniscus type Capillary Structure (Non-inverted Meniscus식 모세관 구조물을 이용한 소형 루프히트파이프에 관한 실험적 연구)

  • Chung, Won-Bok;Park, Soo-Yong;Doctarau, Viachaslau-V.
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2142-2147
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    • 2007
  • Experimental study was conducted to evaluate the performance of a miniature loop heat pipe (MLHP) with non-inverted meniscus type capillary structure. All parts of MLHP in this study were made of copper including the capillary structure and the distilled water was used as a working fluid of MLHP. The outer diameter of evaporator was 9 mm and its length was 119 mm. The effective pore size of the capillary structure was 30 micron and its porosity was 60%. The vapor transport line, the liquid transport line and the condenser were consisted of single 4.0 mm copper tube. The distance between the evaporator and the condenser region was 200 mm and the length of the loop was 969 mm. This MLHP was operated successfully at any orientation but the gravity highly influenced the thermal performance of the MLHP. The maximum thermal load was 130 watts at the bottom heat mode and the 20 watts at the top heat mode.

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Operating Characteristics of a Sintered-Metal Wick/Methanol Loop Heat Pipe Having a Bypass Line (소결금속 윅과 메탄올을 사용하며 바이패스라인이 부착된 루프히트파이프의 작동 특성)

  • Boo, Joon-Hong;Jung, Eui-Guk
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2130-2135
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    • 2007
  • Operating characteristics of a loop heat pipe (LHP) having a bypass line was investigated experimentally. The LHP had a sintered metal wick as a capillary structure and methanol as a working fluid. The sintered metal wick was made of stainless steel of which the average pore size was 5 ${\mu}m$and porosity of 47%. A bypass line of a small diameter was attached between the vapor escape passage and the liquid reservoir. The dimension of the flat evaporator was $50(L){\times}40(W){\times}30(H)$ mm and that of the condenser was $50(L){\times}40(W){\times}11(H)$ mm. Wall and pipe material of the LHP was stainless steel and heating area was 35(W) mm${\times}$35(L) mm. The inner diameters of vapor and liquid transport lines were 4.0 mm and 2.0 mm, and the lengths of the two lines were both 0.5 m. The LHP was tested for three different tilt angles of horizontal, favorite tilt, and adverse tilt. The thermal load range was up to 290 W at the condenser above evaporation position. Furthermore, the effect of a bypass line on the start-up transient as well as steady-state operation was presented and discussed.

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Thermal Performance of a Small-scale Loop Heat Pipe for Terrestrial Application (지상용 소형 루프히트파이프 성능에 관한 연구)

  • Chung, Won-Bok;Boo, Joon-Hong
    • Proceedings of the KSME Conference
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    • 2004.11a
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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.

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Heat Transfer Characteristics of Loop Type Capillary Heat Pipe using R141b as a Working Fluid (R141b를 이용한 루프 세관형 히트파이프의 열전달특성)

  • Kim, Hoon;Ha, Sung-Man;Kim, Tag-Yong;Jeon, Kyung-Whan;Choi, Jae-Hyuck;Yoon, Seok-Hun
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2005.11a
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    • pp.256-257
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    • 2005
  • This paper has been carried out to investigate heat transfer characteristics of loop type capillary heat pipe using R141b as a working fluid. In an experiment heat load are changed from 50W to 250W and the temperature of cooling water is fixed to 20$^{circ}C$ . The heat pipe is composed of 10 turns and outer diameter of heat pipe is 3.2mm. The results show that heat transport rate of this type heat pipe using R141b as a working fluid is good.

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LED Headlamp Thermal Characteristics by Looped Heat Pipe (루프형 히트파이프를 이용한 LED 헤드램프 열적 특성)

  • Noh H.C.;Park K.S.;Kang B.D.;Son S.M.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.443-444
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    • 2006
  • The influence of the heat sources on LED junction temperature are Engine room air, Back plate, Electric power device, and so on. LED lamp cooling system is considered to be an important subject fur high light efficiency. Because LED Chip will be problem When LED junction temperature be over $135^{\circ}C$, In this Study, The Looped Heat Pipe System is considered to prevent LED Chip fall. The LHPS is consist of evaporator part, condenser part, heat pipe part. The working fluid of LHPS is HCFC-123. In this study, to prevent LED Chipfall, we study thermal characteristics for Looped Heat Pipe System with LED lamp.

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