• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.721-724
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• 2011

A system to pressurize propellants stored in propellant tanks is necessary to feed liquid-propellants into combustion devices at the required pressure and flowrate without having cavitation in turbo-pumps. A pressurization system can be categorized into pre-pressurization stage and main-pressurization stage. This report is regarding to a main-pressurization system. Pressurization methods for propellant tanks are divided into pressurant gas generating method and pressurant gas feeding method. One of pressurant gas generating methods uses the vaporized oxygen gas from cryogenic liquid oxygen and non-flammable gas. In this report, both advantages and disadvantages for pressurization methods and types of pressurization systems are compared. Especially the characteristics and principle of pressurization system using impulsive control strategy applied in launch vehicles are introduced. Additionally the structure, schematics, and specifications of heat exchanger, which is one of main units in pressurization system are also discussed. This paper can be utilized to generate the conceptual requirements and to design preliminary configuration of pressurization system during the development of launch vehicle.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2001년도 춘계 학술대회논문집
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• pp.116-120
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• 2001

The impactive Pressure wave induced by pyro valve in the pressurization system of KSR-III may result in fatal failure or malfunction of valves, so it is important to know the pressure wave characteristic in the pressurization system. An unsteady flow analysis in the simplified pressurization system was peformed by Finite difference method.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 한국추진공학회 2005년도 제24회 춘계학술대회논문집
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• pp.168-175
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• 2005

The pressurization system in a liquid rocket propulsion system provides a controlled gas pressure in the ullage space of the vehicle propellant tanks. It is advantage to employ a hot gas heat exchanger in the pressurization system to increase the specific volume of the pressurant and thereby reduce over-all system weight. A significant improvement in pressurization-system performance can be achieved, particularly in a cryogenic system, where the gas supply is stored inside the cryogenic propellant tank. The temperature characteristic of cryogenic pressurant is very important to develop some components in pressurization system. Numerical modeling and Test data were studied using SINDA/FLUINT Program and PTF(Propellant-feeding Test Facility).

• Journal of the Korean Society of Propulsion Engineers
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• 제9권3호
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• pp.66-73
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• 2005

The pressurization system in a liquid rocket propulsion system provides a controlled gas pressure in the ullage space of the vehicle propellant tanks. It is advantage to employ a hot gas heat exchanger in the pressurization system to increase the specific volume of the pressurant and thereby reduce over-all system weight. A significant improvement in pressurization-system performance can be achieved, particularly in a cryogenic system, where the gas supply is stored inside the cryogenic propellant tank. In this study liquid nitrogen was used instead of liquid oxygen as a simulant. The temperature characteristic of cryogenic pressurant is very important to develop some components in pressurization system. Numerical modeling and test data were studied using SINDA/FLUINT Program and PTF(Propellant-feeding Test facility).

• Proceedings of the KSME Conference
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1709-1714
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• 2004

Pressurization system of a 50m unmanned airship was manufactured according to the detailed design. In this paper. the whole procedures including system design. simulation and fabrication were described. The fabricated part were ground tested to check compliances with design requirements. Ground tests include operational tests, leakage tests, endurace tests and low temperature environmental tests. Results shows pressurization system of a 50m unmanned airship meets design requirements. Currently. pressurization system is installed to the KARI airship, Via 50m and performance verification through the flight tests are being conducted.

• Proceedings of the KSME Conference
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• 대한기계학회 2003년도 추계학술대회
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• pp.1384-1387
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• 2003

Pressurization test is usually required in aircraft full-scale static test. There are several test conditions including pressurization of cockpit, fuselage fuel tank, air inlet duct for T-50 full-scale static test. In this paper, the test conditions, equipment, piping analysis for the pressurization test are introduced. Tank simulation test is performed to verify the validity of piping analysis and to find good tuning parameters for the pressurization channel in the servo controller. Several test setup for pressurization of T-50 test is introduced. Test article volume is filled by form, $60%{\sim}80%$ volume is reduced for the T-50 full-scale static test. Pressurization system is connected to servo controller which also controls hydraulic actuator. Load and pressure control is synchronized by using the same servo controller during T-50 test. Typical control result for pressurization test condition is shown. Pressurization tests of T-50 full-scale static test was completed successfully.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제34권11호
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• pp.70-75
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• 2006

The cabin pressurization system response should be consistent with the design limits such as the cabin pressure schedule, the pressure regulation tolerance, the maximum rate of pressure change during normal and abnormal operation and the maximum cabin air inflow rate change. In this paper, the results of pressure loss analysis and flight test for cabin pressurization system of T-50 advanced trainer are introduced. The pressure tolerance at unpressurized condition using calculated exit area of pressurization components through pressure loss analysis is predicted. Pressurization components of D company are selected and the predicted pressure tolerance is in good agreement with flight test results. Finally, T-50 pressurization system is verified by some flight tests of T-50 advanced trainer to comply with various pressurization design criteria of MIL-E-18927.

• Journal of the Korean Society of Propulsion Engineers
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• 제27권1호
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• pp.49-57
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• 2023

The autogenous pressurization has been widely adopted for propulsion systems of next-generation reusable rockets due to its low cost and high reliability. The autogenous pressurization has a simple structure, but an understanding of the heat and mass transfer occurring inside the tank is essential. For this reason, a simulation test of the autogenous pressurization was conceived. The experiment equipment was constructed based on overseas pressurization test facilities cases and expert advice. Unlike the actual autogenous pressurization system, the propellant tank was insulated to exclude external influences. The pressurized gas supply line and the propellant pipe were separated. Using the manufactured autogenous pressure experiment equipment, it is possible to evaluate the condensation phenomenon of pressurants in cryogenic propellants, comparison of the efficiency of pressurization using helium and evaporated gas and the pressurization capacity according to the temperature of pressurant.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.401-404
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• 2008

Pressurization system in a liquid-propellant launcher supplies the controlled gas into the ullage volume of propellant tanks to feed propellants to combustion chamber by pressurizing propellants stored in propellant tanks. The ullage part of propellant tank should be constantly pressurized to supply the propellants stored in propellant tanks to turbo-pump or combustion chamber by pressurant pressurization system. Pressurant used to pressurize propellants is generally stored in a series of tanks at cryogenic temperature and high preassure inside an oxidizer tank. The reason is to store the quantity of pressurant as much as possible and to make pressurant tanks as small as (i.e. as light as) possible. However for test convenience pressurant tank is located at STP (standard temperature and pressure) environment in this study. Orifices are widely adapted to several pressurization systems in liquid rocket propulsion systems. Discharge coefficients of orifices are essentially needed for the optimized design of pressurization system in liquid rocket propulsion system. For this study gaseous nitrogen was served as pressurant and rounded entry orifices were employed. The forty-two (42) rounded entry orifices (the radii of curvatures are 0.5 and 1.0) have been tested experimentally in the supersonic flow region. The discharge coefficients of rounded entry orifices with inside diameters ranging from about 1.4 to 5.0mm was measured with 0.95 ${\sim}$ 0.99.

• International Journal of High-Rise Buildings
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• 제2권4호
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• pp.341-344
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• 2013

During a building fire, smoke can flow through elevator shafts threatening life on floors remote from the fire. Many buildings have pressurized elevators intended to prevent such smoke flow. The computer program, CONTAM, can be used to analyze the performance of pressurization smoke control systems. The design of pressurized elevators can be challenging for the following reasons: (1) often the building envelope is not capable of effectively handling the large airflow resulting from elevator pressurization, (2) open elevator doors on the ground floor tend to increase the flow from the elevator shaft at the ground floor, and (3) open exterior doors on the ground floor can cause excessive pressure differences across the elevator shaft at the ground floor. To meet these challenges, the following systems have been developed: (1) exterior vent (EV) system, (2) floor exhaust (FE) system, and ground floor lobby (GFL) system.