• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.180-183
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• 2006

엔진 밸브와 밸브시트의 마모는 엔진 성능에 영향을 미치는 가장 중요한 요소 중에 하나이다. 엔진 밸브와 밸브시트는 엔진 구동 과정에서 발생하는 고온의 배기가스, 밸브 스프링의 빠른 움직임, 엔진 폭발 과정의 고압, 균일하지 못한 냉각시스템으로 발생하는 실린더 헤드의 뒤틀림이 만들어 내는 극한 환경을 이겨내야 한다. 본 연구에서는 밸브 및 밸브시트의 마모율과 마모 메카니즘을 명확하게 규명하기 위해서 실제 자동차 엔진 내부의 조건인 온도, 밸브와 밸브시트간의 충돌, 스라이딩 등에 관한 것들을 고려하여 밸브 및 밸브시트가 충돌 시험할 수 있는 전용마모 시험기를 사용하였다. 본 연구에 사용된 시편은 현재 실차에 사용되고 있는 밸브와 밸브시트를 사용하였다. 그 종류는 STR35 밸브, STL #6 및 STL #32이다. 밸브시트는 HVS1-2 재질을 사용하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.15-20
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• 2017

The main purpose of the ball valve ball is to be moved by the rotation of the stem when fully open or completely closed. In this study the heat of the initial model, which used a structure interaction analysis technique, tried to examine the structural safety of the high temperature for the ball valve. In the initial model the stress of the exiting sheet was more than the yield strength. We selected two design shapes with variables of length and thickness for the optimization of the sheet. The Kriging interpolation method was applied to a meta-model-based optimization technique. As a result, it was possible to find a thickness and length for the sheet within the yield strength. This was done by measuring the value of the capacity coefficient of the valve and evaluating the performance of the ball valve.

• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.56-58
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• 2001

본 논문은 수두증 환자의 체내에 삽입하는 파릴린 막체크 밸브의 제작과 시험에 관한 것이다. 파릴린 막 체크밸브는 세 가지 특징을 가지고 있다. 박막의 초기 인장응력에 따라 특정한 압력 이상에서 밸브가 열리고, 막과 밸브 입구의 크기에 따라 순방향과 역방향 특성을 서로 다르게 하며, 앤티사이폰 역할을 한다. 파릴린 체크 밸브는 상부 기판과 하부 기판으로 구성되어 있다. 하부 기판은 입구, 출구, 유로, 두 개의 완충챔버로 이루어져 있고, 상부 기판은 입구 박막과 두 개의 완충 챔버 박막으로 이루어져 있다. 하부 기판에는 밸브 구멍 주위에 밸브 시트를 두어 두 기판을 조립할 때 밸브 시트가 막을 변형시키면서 박막에 초기 인장 응력을 주도록 되어 있다. 또, 하부 기판에 특정한 각을 가진 유로 및 완충 챔버를 형성하여 역류 발생시 유체를 완충 챔버 쪽으로 흐르게 한다. 유한요소법(FEM)을 이용하여 박막과 밸브 입구의 크기, 박막의 두께 등을 변화시켜가며 박막의 응력과 변형을 해석하였고 해석 결과로부터 밸브 시트의 높이를 결정하였다. 마이크로머시닝으로 두 기판을 제작하고 조립한 후, 순방향과 역방향의 압력에 대한 유량을 측정하여 파릴린 체크 밸브의 특성을 시험하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.215-215
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• 2014

현재 가장 많이 사용되고 있는 스프링식 안전밸브는 스프링과 설정치 드리프트, 누설 취약성, 채터링에 의한 시트 파손등의 문제점을 지니고 있다. 안전밸브 디스크에서 발생하는 유체 누설은 안전밸브 설정압력 개방에 영향을 주며, 시트(Seat)면의 이물질 삽입, 균열 및 유체에 의한 침식(Erosion) 등에 의해 밸브 핵심 부품이 쉽게 손상되어 기기 성능 저하를 초래하게 된다. 따라서 유체 누설을 조기에 탐지하고 정량화하여 해당 기기의 상태정보 제공을 통한 누설 감지 기법 연구가 요구된다. 원자력 발전소의 경우 밸브에서 유체가 누설되면 밸브의 오작동 및 운전 안정성 저해 요인이 된다. 따라서 본 연구에서는 음향방출법을 이용하여 안전밸브의 유체 누설을 평가하고, 안전밸브의 음향신호 측정 위치 선정 및 누설량에 따른 음향신호를 분석하고자 한다.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.6
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• pp.113-119
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• 2013

A main oxidizer shut-off valve (MOV) controls the supply of cryogenic liquid oxygen to the combustion chamber of liquid rocket engines by on/off operations. The main subjects to be introduced are not only the valve transient response during valve on/off procedures but also the characteristics of pneumatic and seat/poppet parts as core technologies in the development of the MOV, which is expected to be adopted for the Korea Space Launch Vehicle II. It is shown that the analytical prediction of the transient valve travel is in good agreement with experimental results. Friction and elastic forces on the valve moving part are quantitatively evaluated by structural analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.1
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• pp.81-86
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• 2016

The valves used to control or shut off the flow through a pipeline can be divided into many different types, including gate valves, globe valves, and check valves. Globe valves, in particular, have excellent properties, and because they can easily control the flow under high-pressure conditions, they are generally used in LNG ship and steam pipelines. In this paper, a method for changing the shape of a seat was suggested to solve the valve leakage problem from a structural perspective. In addition, the stress distribution and directional deformation were compared for each model. The suggested models were thus validated, and the optimized seat structure, which includes a self-supporting capability for decreasing the amount of leakage, was determined.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.138-144
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• 2000

Degradation occurred at the 6 inch swing check valve in nuclear power plant. Valve replacement and maintenance were carried out during the plant O/H. This report examined the degradation mechanism of the 6 inch check valve by the experimental and theoretical study. Results shows that the degradation was caused by valve chattering which due to the structural and acoustic resonance.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.731-736
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• 2011

A pneumatic driving solenoid valve operates pneumatic control devices by opening/closing operating flow passage when the command is given by control system for the liquid-propellant feeding system of space launch vehicle. The simulation model of pneumatic driving solenoid valve is designed with AMESim to verify the designs and evaluate the dynamic characteristics and pneumatic behaviors of valve. To validate a valve simulation model, the simulation results of their operating durations of valve by AMESim analysis are compared with the results of experiments. In addition, the results of internal flow simulation with FLUENT are utilized to improve the accuracy of valve-modeling. Using the model, we analyze performance of valve; opening/closing pressure, operating time on various design factors; shape of control valve seat, drainage seat, rate of sealing diameter, volume of control cavity. This study will serve as one of reference guides to enhance the developmental efficiency of ventilation-relief valves with the various operating conditions, which shall be used in Korea Space Launch Vehicle-II.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.725-730
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• 2011

A 2-way solenoid valve regulates to maintain the pressure of ullage volume of propellant tanks when the command is given by control system for the liquid-propellant feeding system of space launch vehicle. The simulation model of solenoid valve for pressurization is designed with AMESim to verify the designs and evaluate the dynamic characteristics and pneumatic behaviors of valve. To validate a valve simulation model, the simulation results of their operating durations of valve by AMESim analysis are compared with the results of experiments. Using the model, we analyze performance of valve; opening/closing pressure, operating time on various design factors; shape of control valve seat, basic valve seat, rate of sealing diameter. This study will serve as one of reference guides to enhance the developmental efficiency of ventilation-relief valves with the various operating conditions, which shall be used in Korea Space Launch Vehicle-II.

• Journal of the Korean Institute of Gas
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• v.11 no.1 s.34
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• pp.34-39
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• 2007

In this paper, the FEM result has been presented for a sealing safety between a valve packing and a valve seat during a open and close operation in a LPG cylinder. The sealing operation of a LPG valve is completed when the valve packing in which is made by a nylon-66 polymer is to stop a LP gas flow, which flows out from the outlet of a brass pipe in a LPG cylinder. The contact sealing mechanism of the valve may be classified by a flat contact of an unused valve packing and a circular groove contact of an used valve packing in a current LPG valve. Based on the FEM and experimental investigations the sealing force, 4.9 MPa for a flat contact mode of the unused valve packing is a little high compared to that of the used valve packing, which shows a circular groove contact geometry against a valve seat. But these sealing pressures for two contact modes are very low compared to the ultimate strenath 83 MPa of the nylon-66 and this may be designed with a excess strength of the valve.