• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.928-929
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• 2017

A 75 ton class liquid rocket engine has been developed for KSLV II. Ground firing tests of the rocket engine were conducted to characterize and quantify its structural vibration under combustion testing environments. In this study, evaluation of dynamic response characteristics of the engine system was presented to verify its structural integrity and structural design during ground firing tests.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.140.1-140.1
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• 2014

인공위성은 지상에서 발사된 후 로켓에 의해 임무궤도에 안착을 한 뒤 위성 내부에 탑재된 추진시스템에 의하여 자세 및 궤도제어를 수행한다. 특히, 저궤도 관측위성의 경우 정확한 이미지 촬영을 위해서는 자세제어가 매우 중요하고, 추진체의 잔여량에 따라 인공위성의 수명이 결정되기도 하므로 추진시스템의 역할이 매우 중요하다. 특히, 추진체의 무게에 따라 위성 전체 중량이 좌우되어 발사중량에도 영향을 미치게 되므로 고성능, 저질량의 추진계가 요구되며, 추진계는 극히 미세한 누설도 허용되지 않는다. 개발된 인공위성 추진계 내부의 누설 여부 확인을 위하여 우주환경을 모사한 진공챔버 내부에서 고압으로 충진된 추진 탱크의 누설탐지 시험을 수행하게 된다. 본 논문에서는 지상에서 모사된 우주환경 하에서 인공위성 추진계의 누설 탐지 기법에 대해 알아보고자 한다.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.1
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• pp.21-29
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• 2002

Hybrid propulsion systems provide many advantages in terms of stable operation and safety. However, classical hybrid rocket motors have lower fuel regression rate and combustion efficiency compared to solid propellant rocket motor. The recent research efforts are focused on the improvement of volume limitation and regression rate in the hybrid rocket engine. The present study has numerically investigated the combustion processes in the hybrid rocket engine. The turbulent combustion is represented by the eddy breakup model and Hiroyasu and Nagle and Strickland-Constable model are used for soot formation and soot oxidation. Radiative heat transfer is modeled by finite volume method. To reduce the uncertainties for convective heat transfer near solid fuel surface having strong blowing effect, the Low Reynolds number $\kappa-\varepsilon$ turbulent model is employed. Based on numerical results, the detailed discussion has been made for the turbulent combustion processes in the vortex hybrid rocket engine.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.781-783
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• 2011

The oxidizer filling system, ground facility of the launch complex, should accept difficult requirements from the launcher sufficiently. The launcher do not have unnecessary insulators for mass reduction and manages liquid oxygen mass fastidiously to satisfy the mission requirement. So, the ground facility should be able to accept its requirements, then we should make the operating process being adjusted. In this paper, the operating process design and verification results on the oxidizer filling ground facility for liquid rocket is demonstrated.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.4
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• pp.25-35
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• 2002

A calculation procedure for designing LRE regenerative cooling system is introduced. In LRE thrust chamber, heat is transfered from the hot gas to the wall by convection and radiation, then conduction through the wall and finally convection to the liquid coolant. A cooling channel is designed on the basis of heat transfer rate calculated by using criterial method and integral method. The result is compared with existing Russian cooling channel design code. Also a design logic and quantitative effect of various parameters were introduced to help better understanding for those who is not familiar to LRE system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.750-755
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• 2011

The ignition characteristics of liquid rocket engine thrust chambers which have been developed by domestic technology were analyzed. Analysis results showed that low frequency fluctuation appeared in a partial ignition range according to different temperature profiles and vaporous state in the oxidizer manifold with startup sequences. This low frequency fluctuation wasn't developed as a malfunction factor, but this fluctuation is thought to be taken a continuous concern considering interfaces with engine system and launch vehicle.

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.200-206
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• 2013

A performance sensitivity of liquid rocket engine to propellant density or supply pressure change was studied. The analysis program was verified to have 1% error comparing with the measured data of a turbopump-gas generator system. The engine combustion pressure decreases as fuel supply pressure increases due to decreased mixture ratio which reduces the turbine power. The engine combustion pressure increases as fuel density increases because the total propellant flow rate is increased substantially even though mixture ratio is slightly decreased. The engine combustion pressure increases when the oxidizer density or supply pressure increases.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.913-914
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• 2017

Structural analyses of a engine system is required in development stage for increasing structural reliability and reducing weight. Attitude of a launch vehicle during flight is controlled by combustion chamber rotation varying with TVC (thrust vector control) actuator displacements. In this study nonlinear static analysis is performed for a 75 tonf-class liquid rocket engine using before and after the TVC actuation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2000.11a
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• pp.31-31
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• 2000

초음속 충돌제트(impinging jet)의 열 및 운동량 전달(heat and momentum transfer)은 로켓의 이ㆍ착륙, 다단 로켓의 분리, 로켓의 방향조절을 위해 배기 노즐에 부착되는 제트 베인(jet vane)이나 스포일러 탭(spoiler tab), 수직/단거리 이착륙기의 발진, 미사일 발사시스템, 전투기 동체, 날개, 후미 부분에서 발사되는 미사일의 배기가스가 주변장치 등에 충돌할 때 발생되는 문제점 등을 사전 예측하여 관련장비의 설계 둥에 유용한 자료로 이용된다. 따라서 이에 대한 기초 연구로서 초음속 유동 실험장치를 이용하여 마하수(Mach Number) 1.0 및 1.8인 경우에 대하여 수직/경사평판에서 팽창 비, 거리, 경사각에 따른 충돌 면에서의 단열 벽면온도를 측정하였다. (중략)

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.322-325
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• 2007

This paper shows the development procedure of the low pressure LOX feed system which is used in the liquid rocket with a turbopump. Korean Air has cooperated with KARI in developing the LOX feed system to turbopump. The LOX feed system is characterized with cryogenic temperature and the thin-thickness tube for weight saving. The system in this project is composed with a main feed line and a recirculation line for the LOX temperature conditioning. Each piping system has many components, namely, bellows, filter, orifice, valves, flange and support. In this paper, system design & manufacturing, structural & thermal analyses, and component tests are explained. Finally, the system was assembled to the KARI's PTF test facility and functioned well to meet its required performance.