• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.4
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• pp.98-106
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• 2000

A conceptual design of propulsion system for a geosynchronous communication satellite with 12 years design life is presented in this paper. Propellant mass budget for the design life is calculated using total velocity increment ($\Delta$V) flowed-down from mission requirement analysis. Sizes of the fuel and oxidizer tank are derived based on the calculated propellant mass budget, and mass of the pressurant as well as the size and Pressure of pressurant tank are calculated too. Thruster positioning, number of rocket engines, and position of tank are determined through trade-off study with Structure & Mechanical Subsystem. Propulsion system configuration and its schematics are presented finally.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.4
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• pp.47-58
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• 2002

The pressure regulator has been developed as a pressure-control device of propellant tank in KSR-III. The pressurization system of KSR-III is a basic pressurization system composed of pressurant, He tank and propellant tank. The pressure-control regulator is the most important part of gas-pressurized feed system along with He tank, pyrovalve and He fill valve. The first model of the regulator is tested to satisfy in leakage, strength and basic performance. The second model is tested in the overall test of the KSR-III propulsion system using water. From the test result of the second model, we conclude that the capacity of valve(Cv) must be increased in real system. The third model is modified and tested in the overall test of KSR-III propulsion system using propellant. Finally, the pressure-control regulator is qualified from firing test.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1171-1175
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• 2017

Cryogenic helium gas is used as the pressurant for the oxidizer pressurization of DR(Damper Receiver) sphere in the PSD(Pogo Suppression Device) system and liquid oxygen is used as the oxidizer for the propellant in Korea Space Launch Vehicle-II. The helium gas is stored in pressurant cylinders inside the cryogenic liquid oxygen tank and liquid oxygen is stored in the oxidizer tank. In this study, the performance test of PSD liquid oxygen drain valve for KSLV-II was considered.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.185-191
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• 2016

The Hybrid Safety Injection Tank is a passive safety injection system that enables the safety injection water to be injected into the reactor pressure vessel throughout all operating pressures by connecting the top of the SIT and the pressurizer(PZR). In this study, the condition for balancing the pressure between the Hybrid SIT and PZR was derived theoretically. The pressure balancing condition was set at the point where the velocity of the Hybrid SIT coolant injected into the Direct Vessel Injection(DVI) line was at or above zero. If the condition was derived from a pressure network for the Hybrid SIT, pressurizer, and reactor pressure vessel, the pressure difference between the pressurizer and SIT is less than 0.07 MPa.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.5-10
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• 2005

The geostationary satellite propulsion system has thermistors which can measure liquid propellant temperature at tanks, pipes and etc. In the satellite propulsion system with several tanks, the propellant in the tanks is moved by temperature change and this temperature pattern is constant. In this paper, the temperature change pattern of KOREASAT 1 propulsion system is compared and the prediction study of pressurant inflow using temperature change of geostationary satellite propulsion system is described.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.4
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• pp.1-10
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• 2006

In this paper, a calculation method of the thermodynamic parameters of cryogenic propellant is proposed when a cryogenic propellant tank is pressurized by gaseous helium(GHe) bubbling. Temperature of cryogenic propellant and mass of dissolved GHe into propellant were analyzed at the various operation of pressurization of tile liquid oxygen(LOX) and hydrogen($LH_2$) tank using helium bubbling. It was evaluated how the GHe bubbling influences to the thermodynamic parameters of LOX and $LH_2$ with results of the analysis. With the proposed calculation method, It will be able to confirm the feasibility of GHe bubbling as a pressurization system of cryogenic propellant tank and to optimize the pressurization system using GHe bubbling.

• Proceedings of the KAIS Fall Conference
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• 2012.05b
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• pp.637-639
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• 2012

본 논문에서는 대형 공조기기에서 냉매의 회수시간을 단축하기 위해 진공과 가압방식을 겸용하면서 작업 시 이동이 손쉽게 소형으로 회수 및 충전이 가능할 수 있는 냉매 회수 및 충전 전용기 개발을 하고자 한다. 냉매회수시스템의 작업과정은 냉매회수 장치와 냉동기의 증발기 하부에 충진용 밸브를 호스로 연결하고 진공펌프를 운전하여 저장 탱크 내에 부착된 압력계가 진공상태가 될 때까지 액냉매를 회수 한 후, 자체적으로 증발, 흡입, 액화시켜 탱크내의 온도와 압력을 낮추어 액화된 냉매를 저장탱크로 회수하는 장치로 구성되어 있다.

• 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.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.90-90
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• 2003

한국항공우주연구원은 액체추진기관 시스템을 이용한 3단형과학로켓(이하 KSR-III)을 국내 최초로 개발하여 비행시험을 수행하였다. 액체추진기관 로켓의 비행시험을 위해서는 이전의 고체 추진기관을 이용한 과학로켓 1, 2와는 달리 비행시험 조건에 부합하게 액체추진제 및 가압제 등을 공급하는 지상설비가 필요하다. 이에 한국항공우주연구원은 독자적으로 비행시험에 필요한 제반 설비를 갖춘 발사장을 구축하였다. KSR-III는 압축 헬륨가스(GHe)를 이용하여 연료(Jet A-1)와 산화제(LOx)를 가압하여 추력을 얻는 액체추진기관 시스템이다. 따라서 발사장에서의 지상공급설비는 유공압 설비와 발사시나리오에 따라 해당 부품을 제어하고 자료를 저장하는 제어/계측 설비 및 기타설비들로 구성되어 있다. 지상공급설비 중 유공압 설비는 LOx의 저장 및 기체 내 산화제 탱크의 충전을 위한 산화제 공급설비, Jet A-1의 저장 및 기체 내 연료 탱크의 충전을 위한 연료 공급 설비, 지상설비용 밸브구동 및 기체 내부 퍼지 등에 필요한 질소($N_2$)를 저장/공급하는 설비, 기체내부 밸브 구동 및 가압제로 사용되는 기체헬륨(He)을 저장/공급하는 설비들로 구성되어 있다. 이러한 구축된 공급설비는 기능시험, 연계시험 등의 각종 입증시험을 통해 그 성능을 검증한 후 단인증모델(SQTM)을 이용하여 발사 시나리오에 따른 추진제 공급능력을 입증한 후 KSR-III의 비행시험을 성공적으로 수행하였다. 수행된 연구결과는 향후 건설되어질 우주센터내의 발사장 기반설비 설계의 기초 자료로 활용할 수 있을 것이다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.2
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• pp.93-102
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• 1994

It is the goal of this study to provide the essential data for design and operation of optimum water supply system. Experimental and theoretical analyses have been conducted for various parameters, for example, volume and air percent of pressurizing tank, pump speed and pressure range inside tank, etc. Pressure inside tank with time, flow rate, energy consumption rate and pump operation time have been obtained for design and operating parameters to optimize the components and to establish the operating method of system, and therefore to contribute to the development of technology from a point of view of the improvement of quality, the enhancement of system efficiency and the reduction of construction cost.