• 드라이브 ㆍ 컨트롤
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• 제12권4호
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• pp.1-7
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• 2015

In this study, a spiral valve which is used with a cryogenic linear expander and composed of plural plate coil shapes was examined. Generally, a spiral valve is well known for having excellent efficiency and low noise characteristics. In order to determine the movement characteristics and to investigate the limit of valve displacement, the stress variations according to the changes of operating pressure, displacement and workable temperature are discussed. From this examination, it is considered that the results of this study will significantly facilitate the design and development of a spiral valve for the cryogenic linear expander.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.463-467
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• 2004

This paper presents the fabrication possibility of the micro actuator which uses a micro-thermal bubble, generated b micro-heater under pulse heating. The valve-less micropump using the diffuser/nozzle is consists of the lower plate, he middle plate, the upper plate. The lower plate includes the channel and chamber are fabricated on high processability silicon wafer by the DRIE(Deep Reactive Ion Etching) process. The middle plate includes the chamber and diaphragm d the upper plate is the micro-heater. The Micropump is fabricated by bonding process of the three layer. This paper resented the possibility of the PCR chip operation by the fabricated micropump.

• 한국자동차공학회논문집
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• 제7권8호
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• pp.91-98
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• 1999

This paper describes the air flow characteristics inside the throttle valve. Tow-dimensional steady incompressible Navier-Strokes equation are solved numerically with embedding the conceopt of the artificial compressibility and adopting the Baldwin-Lomax turbulence model. With varying the valve opening angles(the Reynolds number )such as 15$^{\circ}$(5000) , 45$^{\circ}$(3000) , 75$^{\circ}$(7000) and 90$^{\circ}$(10000), respectively. tow cases, with a valve shaft and without one, are analysed. The pressure loss between the entrance and exit is severe at 15$^{\circ}$, 100 times as larger as that of 90$^{\circ}$ case, which also depends much on the existece of the valve shaft. The counter rotating vortices are formed over the valve plate with the shaft at only 75$^{\circ}$. They are smally and very large scale in front and back of the valve shaft , respectively. The velocity profiles of 15$^{\circ}$ and 90$^{\circ}$ at the exit are almost symmetric to the horizontal center line, however, the symmetricity is no longer maintained at 45$^{\circ}$ and 75$^{\circ}$ , and in addition, the flow at 75$^{\circ}$ is enforced a lot below center line. The pressure distribution on the walls is largely changed near the valve shaft, and its magnitude becomes great as the valve angle decreases.

• 대한기계학회논문집A
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• 제35권5호
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• pp.487-494
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• 2011

LNG / LNG-FPSO선박에 사용되는 안전밸브는 배관 시스템으로부터 유체를 방출하여 시스템의 압력을 일정하게 유지시키는데 중요한 역할을 한다. 이러한 안전밸브의 기능적 특성으로 인해 유출계수는 밸브의 성능 중 가장 큰 비중을 차지하며, 선급의 인정을 받기 위해서는 0.8이상의 유출계수가 요구되고 있다. 밸브 성능을 향상시키기 위해서 밸브 내부에서 발생하는 유동특성에 대한 정확한 이해가 필요함에도 불구하고 대부분의 밸브 설계의 경우 현장 작업자들의 경험과 실험에 의한 시행착오에 의존하고 있다. 본 논문에서는 안전밸브에 대한 유동해석을 통해 밸브 내부에 발생하는 압축성 유동현상을 고찰하였고, 실험과 해석에 의한 유출계수를 비교하여 유동해석의 타당성을 검증하였으며, 안전밸브를 지나는 공기의 질량유량을 예측하기 위한 유동해석 모델을 확립하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.320-320
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• 2000

In this paper, a temperature controller of a test plate for semiconductor is developed using LQG/LTR methodology. The liquid is heated or cooled in a tank by a heater of a cooler. The controller controls the flow of heated or cooled liquid in the plate by controling an electronic valve. The developed controller is applied to the plate designed for function test of a semiconductor under high or low temperature environment. As a result, control using the heater and the cooler together shows better control performance than using the heater or the cooler separately.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.704-709
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• 2003

The automobile air conditioning system generally consists of laminated type evaporator, swash plate type compressor, condenser, expansion valve and receiver drier. A swash plate type compressor has been used widely in automobile air conditioning system since 1955, because of wider operation range and better durability than other type compressors. In this study, the performance of an swash plate type compressor with variations of oil charging conditions has been investigated experimentally using the hot gas system. Further, the effects of varying compressor speed on the performance of the compressor has been discussed.

• 공업화학
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• 제10권3호
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• pp.415-418
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• 1999

튜브식 양극판과 겔전해액을 사용한 VRLA (valve regulated Iead-acid) 전지에 있어서 양극 활물질 (active material)의 충전 밀도에 따른 충 방전 싸이클 특성을 고찰하였다. VRLA전지에 사용된 양극 활물질의 밀도는 각각 3.2g/mL, 3.4g/mL 및 3.6g/ml 이었다. VRLA전지는 IU 방식 ($I_{max}=0.2C_{10}/10$, 상한 전압 2.40 v/cell)의 충전과, D.O.D 100%/C5의 방전 방법으로 충 방전 싸이클 수명 시험을 실시하였다. 시험은 $25{\pm}1^{\circ}C$의 항온항습기에서 실행하였다. 시험 결과 활물질 밀도별 VRLA전지의 초기 용량은 밀도와 무관하였다. 즉 3.4g/mL에서 가장 우수하였고, 3.6g/mL에서 가장 낮았다. 충 방전 싸이클에서의 특성은 3.6g/mL인 전지는 3.4g/mL와 거의 유사하였고, 3.2g/mL보다는 크게 우수하였다. 또한 VRLA 전지의 수분고갈 및 열화는 양극 활물질의 충전 밀도가 높을수록 적었다. 이상으로 충 방전 싸이클용 VRLA전지의 양극 활물질의 밀도는 3.4~3.6g/mL이 적절한 것으로 판단되었다.

• 동력기계공학회지
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• 제7권4호
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• pp.61-66
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• 2003

In this paper, the relation between displacement of piezoelectric material and electric field was proposed. FEA was introduced to predict the displacement and reaction force of plate spring attached in the piezoelectric material. The relation between displacement of piezoelectric material forced by plate spring and applied electric field were further verified by experimental investigation. Also, the flow rate of gas in piezoelectric valve was examined by experiment. Finally, the relation between electric field and gas flow was derived. Based on these results, these relations can be used in the design of mass flow controller.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2000년도 유체기계 연구개발 발표회 논문집
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• pp.45-49
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• 2000

Vibration and noise problem in a hydraulic system became one of very important factors in evaluating the performance of a hydraulic system. It is known that vibration and noise in a hydraulic system is directly related to flow pulsation in the hydraulic pump in the system. This study investigated a modeling and simulation technique for pulsating flow in a swash plate type axial piston pump. The key design factors of the pump related to flow pulsation phenomenon of the pump are the physical parameters for notches on the valve plate of the pump. By the numerical analysis, effects of the physical parameters of the notch on the flow pulsation was elucidated.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.101-102
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• 2006

The purpose of this paper is pulsation-analysis of the swash plate type axial piston pump for excavator and the method of side branch hose application, which is used normally in construction equipments. In this paper, draw the mathematical modeling for pressure pulsation mechanism of the swash plate type axial piston pump for excavator, expression the flow pulsation in the pipelines by transfer matrix method, programmed simulation for pulsation by AMEsim software, and the reliability of that was verified by the comparison with the experimental results.