• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.181-185
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• 2006

A liquid rocket fuel-rich gas generator developed for the first time in the country can produce combustion gas over the rate of 4 kg/s at 900 K and 58 bar. The gas can be used not only for driving a turbopump but also for providing heat source for propellant supply tanks. The final design of the gas generator has been fixed based on the concept and preliminary development tests, and was validated through structure and heat transfer analysis. The manufacturing involves precision machining, special surface finish, and welding techniques. The final assessment on the characteristics of ignition and combustion had been carried out through five combustion tests. This concluded that the present product satisfies the development requirements.

• Aerospace Engineering and Technology
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• v.4 no.1
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• pp.171-178
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• 2005

An acoustic analysis of a fuel-rich gas generator for the drive of a turbopump in a liquid rocket engine has been performed and the length of a simulating duct has been determined by comparing the resonant frequency of unstable acoustic modes to simulate an actual flight model gas generator. To simulate more realistically, a realistic short-length simulating duct has been determined by considering 1 or 2 wavelength of the unstable modes. Duct-length adjustment to turbopump can be a method to suppress a combustion instability problem by decoupling of acoustic mode and combustion characteristics. This method has been set up and validated with acoustic analysis and hot firing tests.

• Aerospace Engineering and Technology
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• v.6 no.2
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• pp.197-204
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• 2007

Effect of rotor tip geometry on the performance of supersonic impulse turbine was investigated experimentally. Using the shrouded supersonic impulse turbine of the 30ton class liquid rocket engine turbopump as a base model, the measured performance of de-shrouded rotor was compared. The effect of nozzle-rotor overlap also has been investigated. It has been found that the magnitude of turbine efficiency is largely affected by the existence of the rotor shroud. However, measured efficiency sensitivity of the de-shrouded supersonic impulse turbine with respect to turbine tip clearance was relatively smaller than that of high performance reaction turbine. It also has been found that there exists nozzle-rotor overlap value which results optimum efficiency in supersonic impulse turbine.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.820-823
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• 2017

This study experimentally investigate how the Reynolds number affect cavitation performance in a turbopump inducer using water. Cavitation performance has been determined by the static pressure measured at the inlet of the inducer. Reynolds number has been varied by varying water temperature and inducer rotational speed to maintain constant non-dimensional thermal parameter. At low non-dimensional thermal parameter, the critical cavitation number is insensitive to Reynolds number. However, at high non-dimensional thermal parameter, the critical cavitation number increased as Reynolds number increases. Thus, cavitation performance is deteriorated as Reynolds number increases when thermal effect exists.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.108-111
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• 2017

High performance upper stage engine is necessary for space launch vehicles of geostationary orbit, and staged combustion cycle engine is suitable due to high specific impulse. Technology demonstration model for 9 tonf class staged combustion cycle engine, which is consisted of turbopump, preburner, combustion chamber and supply system, was assembled, and hot-firing test was conducted for three seconds in Upper-stage Engine Test Facility of Naro Space Center. Ignition, combustion and shut down of engine system was performed normally, and its performance parameters were evaluated.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.382-386
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• 2009

The life of a component decreases when it was exposed at the extreme condition. A turbine blade of a turbopump used for a liquid rocket engine is operated under the environment of high temperature and pressure, and experienced high centrifugal force. Thus the durability of the turbopump operated under the these conditions become lower than expected because of the severe fatigue and creep influence. The damage of the turbine being considered the fatigue and the creep influence is estimated to ensure the durability of turbopump turbine. ABAQUS/CAE and MSC.Fatigue are used for the fatigue analysis, and Larson-Miller parameter and robinson's rule are used for the creep analysis. In this paper, comparison and analysis of the fatigue and the creep influence were performed to ensure the life expectancy of turbopump turbine.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.4
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• pp.54-63
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• 2022

A 3-tonf class liquid rocket engine that powers the upper stage of a small launcher and lifts 500 kg payload to 500 km SSO is designed. The small launcher is to utilize the flight-proven technology of the 75-tonf class engine for the first stage. A combination of liquid oxygen and liquid methane has been selected as their cryogenic states can provide an extra boost in specific impulse as well as enable a weight saving via the common dome arrangement. An expander cycle is chosen among others as the low-pressure operation makes it robust and reliable while a specific impulse of over 360 seconds is achievable with the nozzle extension ratio of 120. Key components such as combustion chamber and turbopump are designed for additive manufacturing to a target cost. The engine system provides an evaporated methane for the autogenous pressurization system and the reaction control of the stage. This upper stage propulsion system can be extended to various missions including deep space exploration.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.77-80
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• 2010

A series of hydraulic tests of a Lox pump are performed using water at a room temperature. According to the test results, the Lox pump satisfies its design requirement but both the head and the efficiency do not fully follow the conventional similarity rule. The deviation of the head from the rule is assumed to be due to the increased volute loss at high rotational speed. Furthermore, it is found that when the pump rotates with the flow ratio less then the design requirement the leakage flowrate seems to be increased.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.33-40
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• 2002

The hydraulic performance analysis of a pump system composed of an inducer and impeller for the application on turbopumps has been performed using three-dimensional Wavier-Stokes equations. A simple mixing-plane method and a full interaction method are used to simulate inducer/impeller interactions. The computations adopting two methods show almost similar results due to the weak interaction between the inducer and impeller since the inducer outlet blade angle is rather small. But, because the inducer and the impeller are closely spaced near the shroud region at the interface, flow angles at the impeller inlet show different results between two methods. Thus, the full interaction method predicted about $2\%$ higher pump performance than the mixing-plane method. And the effects of prewhirl at the impeller inlet are also investigated. As the inlet flow angle is increased, the head rise and the efficiency are decreased. The computational results are compared with experimental ones. The computational results at the design point show good agreements with experimental data. But the computation was found to under-predict the head rise at high mass flow rates compared to the experiment, further study must be followed in terms of the computation and experiment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.8
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• pp.99-106
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• 2003

Geometrical design variables are numerically investigated to improve aerodynamic performance of the supersonic impulse turbine of a turbopump in a liquid rocket engine. Aerodynamic redesign was performed for maximization of the blade power. Four design variables considered are blade angle, blade thickness and radii of upper and lower arc blade with appropriate constraints. A fast Navier-Stokes solver was developed and Chien's k-$\varepsilon$ turbulence modelling was used for turbulence closure. In initial shape, a flow separation was found in the middle of blade chord. However, it disappeared in final shape via its geometrical design variable change. About 3.2 percent of blade power was increased from this research.