• Advances in aircraft and spacecraft science
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• v.6 no.5
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• pp.427-442
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• 2019

Small satellites represent an emerging opportunity to realize a wide range of space missions at lower cost and faster delivery, compared to traditional spacecraft. However, small platforms, such as CubeSats, shall increase their actual capabilities. Miniaturized electric propulsion systems can provide the satellite with the key capability of moving in space. The level of readiness of miniaturized electric propulsion systems is low although many concepts have been developed. The present research intends to build a flexible test platform for the assessment of selected small propulsion systems in relevant environment at laboratory level. Main goal of the research is to analyze the mechanical, electrical, magnetic, and chemical interactions of propulsion systems with the modern CubeSat-technology and to assess the performance of the integrated platform. The test platform is a 6U CubeSat hosting electric propulsion systems, providing mechanical, electrical and data interfaces, able to handle a variety of electric propulsion systems, thanks to the ability to regulate and distribute electric power, to exchange data according to several protocols, and to provide different mechanical layouts. The test platform is ready to start the first verification campaign. The paper describes the detailed design of the platform and the main results of the AIV activities.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.3
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• pp.56-60
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• 2017

In hypersonic aircraft, increase of aerodynamic heat and engine heat leads heat loads in airframe. It could lead structural change of aircraft's component and malfunctioning. Endothermic fuels are liquid hydrocarbon fuels which are able to absorb the heat load by undergoing endothermic reactions. In this study, exo-tetrahydrodicyclopentadiene was selected as a model endothermic fuel and experiments were investigated in endothermic fuel cooling system with zeolite catalyst. Three shapes of catalysts have been manufactured and endothermic characteristics were recovered. Bineded catalyst showed higher heat absorption and conversion than other two zeolite catalysts. In product distribution, binded catalyst showed higher aromatics composition.

• Journal of Advanced Marine Engineering and Technology
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• v.10 no.3
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• pp.94-106
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• 1986

Since the oil shock of '70s the engine makers have developed new types of diesel engine with low fuel consumption. There is an obvious tendency towards the use of poorer quality fuels, such as the residual oil from chemical processes of refinery. The shaft driving generators is also widely adopted on behalf of the auxiliary diesel engines, which are driving on the expensive diesel oil and have high fuel oil consumption rates, and some mania propulsion diesel engines are equipped with reduction gear systems to get better propulsive efficiency by slower propeller revolutions. The propulsion shafting system equipped with the shaft driving generator or the geared diesel engine shafting system has flexible couplings, and it requires extensive investigations of the torsional vibration and torque fluctuation in order to ensure the acceptable operation range in service. The characteristics of misfiring must be especially examined for the high viscosity fuels to be used. Both torsional vibration and fluctuating torque resulted from misfiring, should be examined for thier effects on the flexible coupling and propulsion shafting system. This paper is to investigate and solve the above mentioned problems which must be predicted on the design-stage of marine propulsion shafting system. A computer program is developed to calculate the indicated diagram, fluctating torque and torsional vibration for both normal and misfiring conditions.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.4
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• pp.19-26
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• 2002

A chamber enduring 3,000 bars and an electrical high voltage power system have been designed and installed for studying the characteristics of the plasma produced in electro-thermal chemical propulsion system. In order to test the structural characteristics, polyethylene injectors were used which have 4 or 6 mm inner diameter and several lengths from 15 to 70 mm. The capacitors were charged at the voltages of 5.2, 7.3 and 10.4 kV which correspond to 5.58, 11 and 22.3 kJ in charging energy. The observed resistivities of the plasma injector are close to those predicted by a theoretical model that describes the plasma resistivity according to high current density.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.6
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• pp.86-100
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• 2022

In this paper, the concept and characteristics of the nuclear propulsion system were introduced and the state of the art for the nuclear-powered space propulsion in abroad were summarized. Since uranium used in nuclear propulsion has a very high energy density per unit mass, it has exceptional specific impulse performance compared to the existing chemical propulsion method and can reduce the amount of fuel loaded, thereby having advantage for long-distance exploration. For this reason, advanced countries in space development are recently spurring to the research of nuclear propulsion technology, and it is judged that the development of a propulsion engine using nuclear power is absolutely necessary in order to gain an competitive edge on the space development.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.5
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• pp.95-100
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• 2014

In hypersonic aircraft, increase of aerodynamic heat and engine heat leads heat loads in airframe. It could lead structural change of aircraft's component and malfunctioning. Endothermic fuels are liquid hydrocarbon fuels which are able to absorb the heat load by undergoing endothermic reactions. In this study, exo-tetrahydrodicyclopentadiene was selected as a model endothermic fuel and experiments on endothermic properties were investigated with pore structure controlled zeolite catalyst using metal deposition. We secured the catalyst that had better endothermic performance than commercial catalyst. The object of this study is inspect catalyst properties which have effect on heat absorption improvement. Synthetic catalyst could be applied to system that use exo-THDCP as endothermic fuel instead of other commercial catalyst.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.179-182
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• 2007

COMS (Communication, Ocean and Meteorological Satellite) is a geosynchronous satellite and has been developing by KARI and Astrium for Ka-band communication, ocean observation and meteorological observation. COMS Chemical Propulsion System (CPS) uses a bipropellant propulsion subsystem, which is applied for transferring COMS from GTO to GEO (mission orbit) and implementing station-keeping manoeuvres. In this paper COMS CPS is briefly introduced for understanding. A few of mathematical thermodynamic modelings of bipropellant propulsion system in literatures are reviewed and authors has studied those models for developing a computer program, which predicts variations of thermodynamic properties such as temperature and pressure histories in the helium pressurant tank, MMH propellant tank and NTO propellant tank during LAE firing and on-orbit manoeuvrings. The CPS thermodynamic model may be used to compute pressurant and propellant masses and to size tank volumes.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.10
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• pp.1048-1053
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• 2009

It proposes an simple and intuitive method that calculates the equilibrium pressures of a propellant tank by appling the mass conservation principle on the helium in the liquid propellant and in an ullage volume of the propellant tank. A propellant loading analysis program is developed and validated against the existing reference data. And it has applied to the present developing program, COMS Chemical Propulsion Subsystem and the results are compared, it may use to develop a technology of the next geostationary complex satellite's propulsion system.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.3
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• pp.88-95
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• 2019

The hydrogen torch ignition system has been widely used to ignite a pure aluminum for aluminum powder combustion system because of its simple ignition method. However, the conventional hydrogen torch ignition system has a disadvantage that requires a high-pressure tank to supply hydrogen, which leads to the increase of the weight. In order to solve this problem, a hydrogen ignition system using $NaBH_4$, a solid chemical hydride, was designed in this study. The thermal decomposition of $NaBH_4$ was initiated approximately at $500^{\circ}C$ and hydrogen was generated. The parameters affecting the thermal decomposition characteristics of $NaBH_4$ were analyzed and the aluminum combustion test was carried out using $NaBH_4$-based hydrogen ignition system to study the applicability to a practical aluminum-combustion propulsion system.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.2
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• pp.12-20
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• 2000

The numerical analysis, including chemical reaction of an entire ramjet engine is studied to understand the ignition transient mechanism and the dynamic characteristics of the Integrated Rocket Ramjet System comprehensively. Details of how a subsonic combustion environment is established from the supersonic ram air after removal of the inlet port cover, are examined during the ignition transient. Various physical processes are investigated systemically, including ignition, flame propagation, flame dynamics, and vorticity evolution.