• 제목/요약/키워드: Working Fluid Quantity

검색결과 31건 처리시간 0.025초

히트 파이프의 작동유체 충전량이 성능에 미치는 영향 (Effect of Quantity of Working Fluid on Performance of a Heat Pipe)

  • 신동렬;노승탁
    • 설비공학논문집
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    • 제1권4호
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    • pp.313-318
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    • 1989
  • Experiments have been performed to find an optimum filling quantity of working fluid in a heat pipe. The optimum operation has been defined to give a minimum temperature difference between evaporator and condenser. The experimental results show that there exists an optimum filling quantity which is slightly smaller than that calculated by the well known formula from the geometry of the wick. When the concaved vapor-liquid interface at the wick is taken into account to calculate the required quantity of working fluid, the computed value agrees with the experimentally determined quantity.

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PFC 작동유체 사용 U형 히트파이프의 열전달특성 연구 (Heat Transfer Characteristics of the U-shape Heat Pipe using Working Fluid of PFC)

  • 이기우;박기호;전원표
    • 설비공학논문집
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    • 제13권8호
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    • pp.796-802
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    • 2001
  • The purpose of the present study is to examine the heat transfer characteristics of the U-shape heat pipe for the cooling of semiconductor in subway train. Perflouro-carbon(PFC) was used as working fluid. Temperature distribution on the surface and heat transfer coefficients were investigated according to the working fluid volume percent and heating rate. The results were as follows; Optimum volumetric percent of working fluid was from 80% to 90%, and hat transfer coefficients of evaporation and condensation were as follows, respectively. $\hbar_ie=0.37\times(\frac{P_i}{P_O})$l_c}^0.3$,$\hbar_ic-4.2(\frac{\kappa_l^3p_l^2gh_fg}{\mu_lq_c_l_c}^\frac{1}{3}

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밀폐형 2상 열사이폰의 열전달 특성에 관한 실험적 연구 (An Experimental Study on the Heat Transfer Characteristics of Two-phase closed Thermosyphon)

  • 조기현;백이;정형길
    • 한국산업융합학회 논문집
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    • 제5권3호
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    • pp.165-171
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    • 2002
  • The thermosyphon has been used as a heat transmission device in the heat recovery of low level energy and cooling for heat generating equipments. Many studies on the working fluids and wicks have been reported to improve the heat transfer efficiency of the thermosyphon. A low temperature heat pipe with acetone is chosen in the present study to compare the heat transfer characteristics due to pouring amount of working fluid, magnitude of power supplied and tilt angles. The thermosyphon made ⵁ$15.88{\times}0.8t{\times}600mm$ of copper, evaporation section 200mm, insulation section 25mm, condensation 375mm. Heat transfer rate of the thermosyphon increase as magnitude of power supplied increase and observe dry out phenomenon at 5~10% of pouring amount of working fluid. So thermosyphon at the 150kJ/s judged to need 12% or more. Heat transfer rate of the thermosyphon have nothing to do with tilt angles. Dry out phenomenon of the thermo syphon makes it possible that a low temperature thermosyphon may be used to control temperature and heat transfer of a system when the critical quantity of a working fluid is supplied in the thermosyphon.

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고발열 전자부품 냉각용 써모사이폰의 냉각특성에 관한 연구 (Experimental study on the cooling characteristics of thermosyphon for the high power electronic components)

  • 김광수;김원태;송규섭;이기백
    • 설비공학논문집
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    • 제10권2호
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    • pp.137-146
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    • 1998
  • The experimental study is concerned with two-phase closed thermosyphons, (i.e., wickless heat pipes) for the cooling of high power electronic components in telecommunication system. The thermosyphon which can deal with a high heat flux of up to $4.9W/cm^2$ is developed, and the cooling characteristics of thermosyphon is analyzed according to design parameters which are the types of and quantity of working fluid, number of pipes, wire insertion in pipe, inclination angle of thermosyphon, and cooling air velocity. Using water as working fluid is superior cooling performance compared to using acetone, and cooling performance is improved as the number of thermosyphon becomes larger, inserting wires in the pipes, and inclination of $30~60^{\circ}$.

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동관-알루미늄 휜 회전형 히트파이프 열교환기의 성능에 관한 연구 (A Study on the Performance of Rotary Heat Exchanger using Aluminum Finned Copper Tube Heat Pipe)

  • 박기호;이기우;이계중;전원표
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집B
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    • pp.7-12
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    • 2000
  • The purpose of this study is to develop heat transfer analysis program of heat pipe elements and design a revolving heat pipe exchanger by the performance experiment of hot air production by means of middle-temperature waste heat. Experimental variables are the revolution per minute, normal velocity of inlet air and the temperature of waste heat. The revolving heat exchanger has designed as $2^{\circ}$ in inclination angle of heat pipe bundle and as 20% in working fluid quantity and as water in working fluid. Experimental value of the total heat transfer coefficient was $20w/m^2-^{\circ}C$

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절삭유 공급 방식의 신뢰성 평가 기술 (Reliability Evaluation Technology of Metal Working Fluids Supply Method)

  • 강재훈;송준엽;이승우;박화영;박종권
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2002년도 춘계학술대회 논문집
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    • pp.206-208
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    • 2002
  • Metalworking fluids (MWFs) are fluids used during machining and grinding to prolong the life of the tool , carry away debris, and protect the surfaces of work pieces. These fluids reduce friction between the cutting tool and the work surface, reduce wear and galling, Protect surface characteristics, reduce surface adhesion or welding and carry away generated heat. Workers can be exposed to MWFs by inhaling aerosols (mists) and by skin contact with the fluid. Skin contact occurs by dipping the hands into the fluid, splashes, or handling workpieces coated with the fluids. The amount of mist generated (and the result ins level of exposure) depends on many factors. To reduce the potential health risks associated with occupational exposures to MWFs, it is required to establish optimum MWFs supply method and condition with minimum Quantity in all over the mechanical machining field including high speed type heavy cult ing process.

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Study on load tracking characteristics of closed Brayton conversion liquid metal cooled space nuclear power system

  • Li Ge;Huaqi Li;Jianqiang Shan
    • Nuclear Engineering and Technology
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    • 제56권5호
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    • pp.1584-1602
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    • 2024
  • It is vital to output the required electrical power following various task requirements when the space reactor power supply is operating in orbit. The dynamic performance of the closed Brayton cycle thermoelectric conversion system is initially studied and analyzed. Based on this, a load tracking power regulation method is developed for the liquid metal cooled space reactor power system, which takes into account the inlet temperature of the lithium on the hot side of the intermediate heat exchanger, the filling quantity of helium and xenon, and the input amount of the heat pipe radiator module. After comparing several methods, a power regulation method with fast response speed and strong system stability is obtained. Under various changes in power output, the dynamic response characteristics of the ultra-small liquid metal lithium-cooled space reactor concept scheme are analyzed. The transient operation process of 70 % load power shows that core power variation is within 30 % and core coolant temperature can operate at the set safety temperature. The second loop's helium-xenon working fluid has a 65K temperature change range and a 25 % filling quantity. The lithium at the radiator loop outlet changes by less than ±7 K, and the system's main key parameters change as expected, indicating safety. The core system uses less power during 30 % load power transient operation. According to the response characteristics of various system parameters, under low power operation conditions, the lithium working fluid temperature of the radiator circuit and the high-temperature heat pipe operation temperature are limiting conditions for low-power operation, and multiple system parameters must be coordinated to ensure that the radiator system does not condense the lithium working fluid and the heat pipe.

내부 그루브를 가진 열사이폰의 작동유체 봉입량 변화에 따른 열전달 성능에 관한 연구 (A Study on Heat Transfer Performance with the Changes of Working Fluid Filling Ratio for Thermosyphon with Internal Groove)

  • 예석수;한규일
    • 동력기계공학회지
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    • 제4권3호
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    • pp.19-24
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    • 2000
  • This study concerns the performance of the heat transfer of the thermosyphon having 80 internal groove in which boiling and condensation occur. Distilled water has been used as a working fluid. The liquid filling as the ratio of working fluid volume to total volume of thermosyphon has been used as the experimental parameters. The heat flux and heat transfer coefficient at the condenser are estimated from the experimental results. The experimental results have been assessed and compared with the existing theories. As a result of the experimental investigation, the maximum heat flow rate in the thermosyphon is proved to be dependent upon the liquid fill quantity. relatively high rates of heat transfer have been achieved operating in the thermosyphon with the internal groove. Also, a thermosyphon with the internal groove can be used to achieve some inexpensive and compact heat exchangers in low temperature. In addition, overall heat transfer coefficients and the characteristics as an operating temperature are obtained for the practical applications.

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