• Aerospace Engineering and Technology
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• v.4 no.2
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• pp.135-141
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• 2005

The procedure of conceptual and detailed design of sub-scale combustor using bipropellant swirl or impinging injector with external or internal mixing for a liquid rocket engine are described in this paper. The sub-scale combustor uses liquid oxygen(LOx) and kerosene as propellants and has a injector head, an ablative material combustor wall and a water cooled nozzle. The injector head has LOx manifold, fuel manifold, fire face plate, one center swirl or impinging injector and 18 main swirl or impinging injectors.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.100-106
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• 2020

Turbopumps for liquid rocket engines are exposed to various cavitation instabilities under their operating conditions. The instabilities affect the stability of the turbopumps. To make sure of the stability of the turbopump of KSLV-II, the present work examined the characteristics of the cavitation instabilities during the turbopump assembly test. In the test, the LOx pump was operated under super-synchronous rotating cavitation and attached to uneven cavitation. In the vibration analysis of the fuel pump, the characteristic frequency by the super-synchronous cavitation of the LOx pump was clearly shown.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.4
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• pp.76-81
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• 2003

To investigate the convective heat transfer phenomena inside the Lox/Kerosene liquid rocket combustion chamber, hot fire tests were performed by using a water-cooled calorimetric chamber. The calorimetric chamber consists of one cylindrical section and nozzle section with independent cooling passage. To measure the heat flux, thermocouples were installed inlet and outlet of cooling passage of each section. The investigated range of combustion chamber pressure is from 100 psi to 300psi at fixed O/F ratio of 2.0 and radiation heat transfer from the hot gas to the surface is not considered. The measured heat flux was almost linearly depended on the chamber pressure.

• Natural Product Sciences
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• v.22 no.4
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• pp.225-230
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• 2016

Phytochemical investigation from the stem bark of Beilschmiedia pulverulenta resulted in the isolation of five lignans, (+)-yangambin (1), (+)-sesartemin (2), (+)-excelsin (3), (+)-sesamin (4), and (+)-syringaresinol (5), together with lupeol (6), lupenone (7), ${\beta}-sitosterol$ (8), and ${\beta}-sitostenone$ (9). Their structures were established by the analysis of their spectroscopic (1D and 2D NMR) and spectrometric (MS) data, as well as by comparison with those reported in the literature. The isolated lignans were tested for their anticholinesterase (AChE: acetylcholine esterase and BChE: butyryl cholineesterase) and anti-inflammatory (COX-2: cyclooxygenase-2 and LOX: lipoxygenase) activities. All the isolated lignans (1 - 5) exhibited significant inhibition activities in AChE/BChE and COX-2/LOX assays with $IC_{50}$ values ranging from $168.8-504.2{\mu}M$ and $21.0-59.4{\mu}M$, respectively.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.6
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• pp.71-75
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• 2005

An experimental study was carried out to investigate the effect of film cooling in the lab-scale dump-cooled liquid rocket engine using LOX and kerosene as propellants. The nozzle of the rocket engine was film cooled with water as coolant. A special film cooling adapter was fabricated to introduce the film-coolant into the thrust chamber. The flow rates of film coolant was approximately 15~19 percent of the total propellant. The nozzle heat flux was determined from the measured temperature rise and flow rate of the coolant(water). Large reductions in the nozzle heat flux was resulted when film cooling adapter located directly upstream of the nozzle.

• 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.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.477-480
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• 2011

The stress analyses of the 'U'-shaped multi-ply reinforced gimbal bellows under high pressure and rotational displacement loadings are performed at the room and cryogenic temperatures. The bellows are used for the Lox pipe line which connects the combustion chamber with the turbopump of a liquid rocket engine. The distributions of the stress, the strains and the contact pressures are obtained from the finite element analysis considering the geometric non-linearities of the contacts between the plies and the material one of the isotropic plasticity. Those are compared with the stress results from EJMA (Expansion Joint Manufacturing Association) standard. Also, the effects of the operating temperature and the reinforcing ring on the stresses are investigated.

• YAKHAK HOEJI
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• v.56 no.2
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• pp.80-85
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• 2012

Previously, we have reported that arachidonic acid (AA) appears to be involved in the induction of apoptosis in HepG2 human hepatoblastoma cells. In this study we investigated the possible role of the NADPH oxidase, a membranebound enzyme generating reactive oxygen species (ROS), in the mechanism of AA-induced apoptosis in HepG2 cells. Apoptotic cell death induced by AA was significantly suppressed by various inhibitors of the NADPH oxidase, diphenylene iodonium (DPI), apocynin (Apo) and neopterine (NP). In addition, these inhibitors of the NADPH oxidase completely blunted the AA-induced ROS elevation. Next, we investigated the implication of metabolic pathway of AA in these AA actions. Both apoptosis and ROS production induced by AA were not significantly altered by treatment with indomethacin (Indo) or nordihydroguaiaretic acid (NDGA), selective inhibitors of cyclooxygenase (COX) and lipoxygenase (LOX), respectively, suggesting that AA metabolites produced by COX or LOX may not have an essential role in the AA-induced apoptosis and ROS generation. Collectively, these results suggest that the NADPH oxidase may be a key player in the mechanism of AA-induced apoptosis in HepG2 cells. These results further suggest that NADPH oxidase may be a good target for the management of human hepatomas.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.150-153
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• 2006

Gas generator should be adopted either fuel rich or oxidizer rich combustion because of the temperature restriction to avoid any possible thermal damages to turbine blade. This study focuses to model the non-equilibrium chemical reaction of kerosene/LOx with detailed kinetics developed by Dagaut using Perfectly stirred reactor(PSR) assumption. To predict more reliable species fraction and other gas properties, Frenklach's soot model was added to Dagaut's detailed kinetics.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.107-110
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• 2009

A basic design for a Technical Development Model (TDM) of liquid oxygen lines from the turbopump exit to the oxidizer valves of the combustion chamber and the gas generator was conducted to develop a turbopump-fed liquid rocket engine. The TDM is composed of straight lines, elbows, bellows, a branch, an orifice, flanges and a heat insulator. Materials were determined by consideration of operation conditions, weight constraint and manufacturing procedures. The size and the location of each component were determined by flow analysis of the required flowrate and the pressure loss. Basic designs of the components were conducted by consideration of the operating temperature and the maximum expectation operating pressure. The safety factors were evaluated by structural analysis of design of each component.