• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.4
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• pp.19-27
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• 2021

In this study, a high-pressure subsacle thrust chamber was developed to verify the core technology for KSLV-II performance enhancement. The core technologies are the design of an injector for high-pressure combustion, development of a combustion stabilization device using the additive manufacturing technique, and the design and fabrication of mixing head and regeneratively cooled combustion chamber. The core technologies, which have been verified through the development of high-pressure subscale thrust chamber, will be used to develop large engine liquid rocket engine thrust chamber in the future.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.574-577
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• 2012

Thrust measuring is one of the crucial factor to decide the performance of a liquid rocket engine when the engine development test, especially for the combustion chamber, is implemented. Calculating the thrust from a combustion pressure is used when direct measuring the thrust is impossible, but direct measuring the thrust is necessary and various methods for doing it more precisely should be considered. This paper introduces the preliminary design concept about the new thrust measurement system for the vertical firing test stand, which is introduced domestically for the first time, of a liquid rocket engine combustion chamber.

• International Journal of Aerospace System Engineering
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• v.5 no.2
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• pp.16-22
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• 2018

An analysis has been made on the performance variation due to pressure drop change at propellant supply pipes of liquid rocket engine. The objective is to compare the effectiveness of control variables to tune the liquid rocket engine performance. The mode analysis program has been used to estimate the engine performance for different modes which is realized by controlling the flow rate of propellant. The oxidizer of combustion chamber, the fuel of combustion chamber, the oxidizer of gas generator and the fuel of gas generator are the independent variables to control engine thrust, engine mixture ratio and temperature of gas generator product gas. The analysis program is validated by comparing with the powerpack test results. The error range of compared variables is order of 4%. After comparison of tuning effectiveness it is turned out that the pressure drop at oxidizer pipe of gas generator and pressure drop at combustion chamber fuel pipe and the pressure drop at the fuel pipe of gas generator can effectively tune the thrust of engine, mixture ratio of engine and temperature of product gas from gas generator respectively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.454-456
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• 2012

Conceptual design results of a thrust chamber for a 7 tonf-class liquid rocket engine of KSLV-II 3rd stage were described. The engine system for KSLV-II 3rd stage is pump-fed system, the thrust chamber has vacuum thrust of 6.9 tonf, vacuum specific impulse of 336.9 sec, chamber pressure of 70 bar, nozzle expansion ratio of 94.5, total propellant mass flow rate of 20.5 kg/s, mixture ratio(O/F) of 2.45. The thrust chamber consists of mixing head with 90 coaxial swirl injectors and regeneratively combustion chamber cooled by kerosene.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.25-28
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• 2010

The Cold flow and ignition tests have been performed for a technology demonstration model of 75-tonf liquid rocket engine thrust chamber which was designed and manufactured on the basis of the previous development experience of a 30-tonf liquid rocket engine thrust chamber. The hydrodynamic characteristics of the facility supply pipelines and the filling time of the cooling kerosene were obtained through the cold flow tests. The ignition cyclogram was determinded using the results and the ignition test was successfully carried out. The acquired data and test technique of present ignition test will be used in hot firing tests.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.54-58
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• 2017

A combustion instability has been one of the most serious problems in the development of combustion devices including rocket engine and gas turbine. In particular, a high-frequency combustion instability generated by resonant coupling between combustion phenomena and acoustic oscillations within thrust chamber causes severe damage to the hardware. Because it is accompanied by high amplitude pressure oscillations and excessive heat flux to the chamber wall. Therefore, combustion instability is one of the difficult problems that must be resolved in developing liquid rocket engine. This paper describes the cases of combustion instability encounted during the development of thrust chamber for KSR-III and KSLV-II.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.6
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• pp.73-78
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• 2012

The ignition characteristics of liquid rocket engine thrust chambers which have been developed by domestic technology were analyzed through hot-firing tests. Thrust chambers used in hot-firing tests have different characteristics in terms of the injector for ignition, film cooling method and the position of the oxidizer inlet. Also, these thrust chambers used their respective startup sequences. Analysis results showed that according to temperature profiles of the oxidizer manifold, low frequency fluctuation was appeared in ignition area. This low frequency fluctuation didn't give rise to violent malfunction of the thrust chamber, but the continuous observation as a concern parameter in the side of interfaces with engine system and launch vehicle should be demanded.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.750-755
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• 2011

The ignition characteristics of liquid rocket engine thrust chambers which have been developed by domestic technology were analyzed. Analysis results showed that low frequency fluctuation appeared in a partial ignition range according to different temperature profiles and vaporous state in the oxidizer manifold with startup sequences. This low frequency fluctuation wasn't developed as a malfunction factor, but this fluctuation is thought to be taken a continuous concern considering interfaces with engine system and launch vehicle.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.249-252
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• 2012

Structural design of the injector head part of a 7ton class thrust chamber was preformed. Structural stability of an injector head part is a very important factor for a thrust chamber of a liquid rocket engine because it is loaded by high pressure of liquid oxidizer and fuel in addition to thrust load. Structural design requirements were first defined to design the injector head part of the 7ton class thrust chamber and the basic configuration was designed on the basis of the design requirements. A high strength steel that has been locally developed was applied to the injector head part of the thrust chamber. A total of twelve design configurations have been analyzed to select structurally the most stable design configuration.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.4
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• pp.71-80
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• 2010

The KSLV-II(Korea Space Launch Vehicle-II) which being a successor of the KSLV-I is a space launch vehicle capable of delivering 1.5 ton-class satellite into a low earth orbit. The development of a 75 tonf-class liquid rocket engine(LRE) is planned on the basis of the technologies mastered through the preceded research of a 30 tonf-class LRE. The thrust chamber of the LRE is required to have higher combustion stability, structural integrity and thermal durability. This paper deals with the design requirements of the 75-tonf thrust chamber and a variety of technical considerations which have been conducted analytically in the course of the design for the realization of the requirements.