• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.10
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• pp.1083-1088
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• 2011

The effects of an impeller and floating ring seals on the performance of centrifugal pumps are investigated on the basis of their test results using water. The pumps are single-staged centrifugal pumps developed for 30-ton- and 75-ton-class liquid rocket engines, and are components of a turbopump that supplies propellants (liquid oxidizer and kerosene) to the combustion chamber. The exit width of the impellers and the numbers and exit angles of the impeller blades are found to have influences on the pump heads. In addition, the pumps have different efficiencies according to the gaps between the floating ring seals and the impellers, whereas the pump size seems to have less effect on the efficiency.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.61-68
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• 2020

7-tonf turbopump real-propellant tests in Naro Space Center were conducted and high-frequency signals from an accelerometer and pressure sensors installed on the casing and the inlet/outlet pipeline of LOX pump were analyzed to estimate the structural and hydrodynamic stabilities. Waterfalls, frequency spectrums and RMS(Root Mean Square) values of the measured signals were calculated and characteristic instability frequencies by the rotating cavitation and the rear floating ring seal(F.R.S) were investigated. Static pressures of the inlet/outlet pipeline and an acceleration of the pump casing are strongly affected on pressure fluctuation induced by the rear floating ring seal in the leakage path. Despite the acceleration RMS value seems totally small, the rotating-speed-related synchronous frequency affecting the shaft instability is distinctly observed in the frequency contour.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.159-162
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• 2008

In this study, various cycles of liquid rocket engines were surveyed and specifically gas generator after burning cycle was investigated for upper stage motors. The engines for the upper stage can be categorized into three group based on the cycles and propellants at the diagram. Kerosene engines which adapt the gas generator after burning cycle and are located in the region II, are characterized for high combustion pressure and complexity. This cycle usually needs more than two pumps to use the turbine power efficiently. The fuel line can be divided into the gas generator line and the combustor line, and only the gas generator line is need to be pressured more because the combustion pressure in the gas generator is much higher than that of the combustor. Basically, all the oxidizer goes into the gas generator and than to the combustor, thus the auxiliary LOx pump is not critically necessary. However, for the various reasons, the LOx line requires a booster pump. A gas generator after burning cycle engines produces relatively high specific impuls than that of the open cycle engines. Thus it is suitable for upper stages of launch vehicles.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.864-870
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• 2017

The propellants are burned in the pre-burner of the staged combustion cycle engine, and the resulting hot gas drives the turbine, and the turbine operates the turbo pump. The burned gas passing through the turbo pump is supplied to the combustor at high temperature and high pressure, where the gas is supplied in an excess of fuel or an excess of oxidant depending on the amount of fuel or oxidant. When the cycle works at oxidizer-rich staged combustion, its metal pipe can ignite or explode by the impact of even small particles. In this study, we develop the powder combinations for anti-oxidation coating through the analysis of other coating materials and establish the coating process.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.238-241
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• 2003

In case of liquid rocket using turbopump, the inner pressure of liquid oxygen tank is maintained low, so vaporization of LOX is generally occurred. This vaporization tendency increases as the inlet helium gas temperature is higher. For estimating the amount of helium in the rocket system, the LOX vaporization phenomena should be carefully considered. In this paper, Inner process of LOX tank is analyzed by two phase flow modeling. the vaporization rate and required Helium mass is investigated with varying inlet helium temperature and heat transfer coefficient.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.1
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• pp.35-44
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• 2011

Mathematical modelling for liquid rocket engine(LRE) main components were conducted to predict the dynamic characteristics when the LRE operates at the transient condition, which include engine start up, shut down, or thrust control. Propellant feeding system is composed of fuel and oxidizer feeding components except for regenerative cooling channel for the fuel circuit. Components modeling of pump, pipe, orifice, control valve, regenerative cooling channel and injector was serially made. Hydraulic tests of scale down component were made in order to validate modelling components. The mathematical models of engine components were integrated into LRE transient simulation program in concomitant with experimental validation.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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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.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.4
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• pp.104-111
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• 2019

Staged combustion cycle engines exhibit higher combustion performance compared with open cycle engines with a gas generator. An advanced research of the staged combustion cycle engine is going on for the next program following the KSLV-II program. Various experiments have been carried out for the technology demonstration model, TDM0A and TDM0B. The experiments on the combustion performance are aimed to understand the engine start condition and combustion characteristics. They also aim to develop the oxidizer-rich pre-burner and the combustor of the staged combustion cycle engine. The engine-shaped model, TDM1A is fabricated based on the experimental data. The combustion experiment of the TDM1A shows that the combustion pressure of the combustor is approximately 91 bar and the turbine rotation is approximately 28,00 rpm. The result is stable and satisfies the development requirements. The present paper reports on the development process and characteristics of engine models from TDM0A to TDM1A.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1080-1083
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• 2017

In the design of KSLV-II, there is a scenario in which supercooled liquid oxygen is supplied to prevent a geysering phenomenon in the oxidizer pipe and a cavitation phenomenon at the pump inlet. To verify this condition in the engine development test phase, a system that supplies supercooled liquid oxygen to the engine was applied in the engine combustion test facility. In this system, supercooling methods using a vacuum ejector and using helium injection to the tank were appied. Both tests were carried out for about 17 minutes. Supercooling results of about 3.3K for the ejector test and about 2.2K for the helium injection test were obtained at the 50% level of the tank.

• Journal of Biomedical Engineering Research
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• v.40 no.5
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• pp.197-205
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• 2019

The existing Extracorporeal membrane oxygenation(ECMO) and Cardiopulmonary bypass system(CPB) have been developed and applied to various devices according to their respective indications. However, due to the complicated configuration and difficult usage method, it causes inconvenience to users and there is a risk of an accident. Therefore, smart all-in-one cardiopulmonary circulation device is being developed recently. The smart all-in-one cardiopulmonary assist device consists of a blood pump for cardiopulmonary bypass, a blood oxidizer for cardiopulmonary bypass, a blood circuit for cardiopulmonary bypass, and an artificial cardiopulmonary device. It is an integrated cardiopulmonary bypass device that can be used for a variety of purposes such as emergency, intraoperative, post-operative intensive care, and long-term cardiopulmonary assist, combined with CPB used in open heart surgery and ECMO used when patient's cardiopulmonary function does not work normally. The smart all-in-one cardiopulmonary assist device does not exist as a standard and international standard applicable to advanced medical devices. Therefore, in this study, we will refer to the International Standard for Blood Components, the International Standard for Blood, the Guideline for Blood Products, and prepare applicable performance and safety guidelines to help quality control of medical devices, and contribute to the improvement of the health of people. The guideline, which is the result of conducted a survey of the method of safety and performance test, is based on the principle of all-in-one cardiopulmonary aiding device, related domestic foreign standards, the status of domestic and foreign patents, related literature, blood pump(ISO 18242), blood oxygenator (ISO 7199), and blood circuit (ISO 15676) for cardiopulmonary bypass.The items on blood safety are as follows: American Society for Testing and Materials ASTM F1841-97R17), and in the 2010 Food and Drug Administration's Safety Assessment Guidelines for Medical Assisted Circulatory Devices. In addition, after reviewing the guidelines drawn up through expert consultation bodies including manufacturers / importers, testing inspectors, academia, etc. the final guideline was established through revision and supplementation process. Therefore, we propose guidelines for evaluating the safety and performance of smart all-in-one cardiopulmonary assist devices in line with growing technology.