• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.538-541
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• 2009

소형엔진의 성능을 결정하는 흡기시스템 중 흡기포트는 매우 중요한 설계인자이다. 본 연구는 흡기포트에 대한 성능실험 및 CFD(Computaional Fluid Dynamics) 해석을 통하여 흡기 성능을 파악하고, 이러한 일련의 실험과정을 학습하여 제품의 성능 평가 절차를 정립하고 성능을 개선하는데 그 목적이 있다. 흡기 성능평가를 위해 리그를 구성하여 실험과 해석을 진행하였으며 이를 통하여 공기유량계수 값을 획득하였다. 공기유량계수 값은 밸브 리프트 변화에 따른 표준 밸브리프트로 환산한 값을 사용하였다. 실험적 연구를 통하여 기존 소형엔진 흡기 포트의 평가에 대한 기준을 제시하였고, 이는 소형엔진 흡기포트 설계 후 성능 평가를 위한 중요한 지표로 사용될 수 있을 것으로 판단된다.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.6
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• pp.35-41
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• 2007

The rate of loading in motor operated valve(MOV) can be defined as a variation of correlation between the actuator torque and the thrust upon the variation of operating load. This paper contains the analysis of characteristic and the validity of loading rate in the opening stroke of gate type motor operated valve. Also, this paper describes the evaluation result of loading rate for 40 MOVs' opening stroke using newly derived methodology in this study. Author has found a result that loading rate of opening stroke gets a negative value when the differential pressure is higher than 150 psi and this value goes up depending on the amount of the differential pressure.

• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.84-90
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• 2012

Fuel shutoff valve of a combustion chamber controls propellant mass flowrate of a rocket engine, by using pilot pressure and spring force. The developing fuel shutoff valve can be self sustained even though pilot pressure is removed in an actuator. Therefore, it is necessary to analyze the characteristics of the forces with respect to the opening and closing of the valve in order to evaluate its performance. In light of this, the valve has been designed to adjust the control pressure for the opening of the poppet and to determine the working fluid pressure at which the valve starts to close. This paper also has been predicted flow coefficient of the valve by Fluent(ver. 12.0) CFD analysis. Various results from the prediction and the analysis have been compared with experiments.

• 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.

• 기계와재료
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• v.26 no.1
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• pp.50-62
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• 2014

원전발전소에 납품되는 원전용 안전밸브의 성능은 ASME나 KEPIC와 같은 기술기준코드에 따라 설정압력, 블로우다운(blowdown), 풀리프트(Full lift), 누설(leakage), 방출용량(discharge flow rate)등과 같은 특성인자로 평가된다. 그 중에서도 방출용량은 ASME SEC III NB 7000 코드에 따라 ASME 용량인증이 요구되지만, 아직 국내에는 국제적으로 공인되니 압력방출장치 용량시험기관이 부재하여 외화유출 및 국내 PRD 기술개발에 많은 어려움이 있어왔으며, 이에 따라 원전 PRD 인증기관 개발을 통하여 세계적인 인프라 구축의 필요성이 부각되고 있다. PRD 인증기관 구축은 국내 원전 핵심기자재의 고급기술 국산화에 이바지 할 수 있고, PRD 성능 및 용량시험지원을 통하여 국내 밸브기술 경쟁력 확보하는 데 기여할 것으로 기대된다.

• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.83-83
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• 2004

상용프로그램인 AMESim을 이용하여 제어밸브 성능시험설비에 대한 Transient 구간에서 문제점 발생 확인과 동시에 시스템에 최적화를 통한 비용 절감효과를 위해 본 Simulation을 수행하였다. 가압 자동 조절 시스템은 직렬식과 병렬식 두 가지에 대해 고려했을 경우 직렬식이 더 타당함을 확인하였고, 특히 Tank Ullage의 압력 분포를 보면 직렬식에서 Fluctuation이 약 $\pm$0.2%이고, 병렬식에서 약 $\pm$0.7%가 됨을 보았다. (중략)

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.3-6
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• 2007

In this study, we described the Pyrovalve used in the propulsion system. It is very important to ensure its reliablity of operation because Pyrovalve is a pyrotechnic device for controlling fuel and air line of propulsion system. so we focused on improving operational reliability through several analyses and tests.

• Journal of the KSME
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• v.30 no.6
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• pp.564-571
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• 1990

최근의 기관은 DOHC 또는 SOHC로 4밸브나 5밸브를 채용하여 흡기계의 효율향상을 시도하고 있다. 그러나 고속성능에 중점을 두고 기관제원을 설정하게 되면서 저속 실용역에서 토크의 저하를 초래하는 경우가 많아지고 있으며 금후 이러한 문제의 해결에 많은 노력이 계속될 것으로 전망된다. 또한 전자기술의 발전과 자동차에 대한 적용 기술이 향상됨에 따라 앞으로 가변흡기 시스템, 가변밸브 타이밍, 가변 터보, 가변 기통수, 가변 압축비등 가변기술에 대한 연구개발이 더욱 활발히 이루어질 것이다.

• Aerospace Engineering and Technology
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• v.11 no.2
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• pp.109-116
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• 2012

A vent-relief valve performs as a safety-valve assembly for liquid propellant feeding system of space launch vehicle, which relives pressurant propellant tanks during the filling and the flight. At vent mode, valve is opened and closed by driving pneumatic pressure, and at relief mode, valve is automatically operated to set relief pressure. In this study, we have analyzed a basic layout of vent-relief valve which is designed using foreign LVs(Saturn) to satisfy requirements of Korean Space Launch Vehicle. The simulation model of vent-relief valve is designed by using the AMESim code to verify design parameters and evaluate pneumatic behaviors of valve. In this study, we performed dynamic characteristic simulations on design parameters. And we could predict opening/closing time and pressures, operating performances on design parameters. Using this results, we could suggest detail design and boundary conditions of design.

• 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.