• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.1
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• pp.103-115
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• 2013

Durability testing method trends of the thermal barrier coating(TBC) for the combustion chamber of the liquid-propellant rocket engine have been investigated. Many types of the durability testing method such as the mechanical tests to measure surface cohesion force, the thermal fatigue tests with laser, furnace, burner or plasma, the small scale combustion tests using injectors, and the thermo-mechanical fatigue tests were observed. The TBC with sufficient durability can be selected for the use of combustion chamber through such specimen-level tests and the durability can be verified by the tests using the real scale combustion chambers.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.259-264
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• 2004

The critical component of combustor having high combustion efficiency for high performance liquid rocket engine is injector. The results of design and hot firing tests of six sub-scale combustors which have respectively an impinging type injector(1ea.), an bi-propellant swirl closed injector(1ea.), and hi-propellant swirl mixed injector(4ea.) were described in this paper. The combustion test were successfully performed. The combustion efficiency have higher value than predicted value and high frequency combustion instability does not occur.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.603-615
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• 2012

Durability testing method trends of the thermal barrier coating(TBC) for the combustion chamber of the liquid-propellant rocket engine has been investigated. Many types of the durability testing method such as the mechanical tests to measure surface cohesion force, the thermal fatigue tests with laser, furnace, burner or plasma, the small scale combustion tests using injectors, and the thermo-mechanical fatigue tests were observed. The TBC with sufficient durability can be selected for the use of combustion chamber through such specimen-level tests and the durability can be verified by the tests using the real scale combustion chambers.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.91-99
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• 2020

A liquid rocket engine goes through many tests to prove its performance before liftoff. It means the tests for setting ignition and start-up conditions or a test on design condition, which verifies the design performance. However, the development process requires verification of performance under off-design conditions through tests involving different operating conditions, which affects the duration of engine development. The off-design performance test is performed by altering the conditions of the propellant supplied to the engine in conjunction with the engine performance test that varies the opening of the control valves in the engine. This paper is based on the results of the engine tests performed at the KSLV-II engine test facilities in the Naro Space Center and describes the operations of the test facility for off-design condition test that changes the inlet conditions of the turbo-pump due to changes in the pressure and temperature of the propellant supplied to the test engines.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.4
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• pp.73-78
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• 2011

When a liquid rocket engine - specifically for the gas-generator cycle engine has throttle valves to control the thrust level and mixture ratio of the engine, it is possible to adjust the inherent flow characteristics of the control valves in order to secure a linearized correlation between the control-process-parameters like the thrust or mixture ratio of an engine and the throttle angle of valve. These linearities can reduce the complexity of the control process and make the process more explicit by ensuring the intuitive control. In this point, we proposed an algorithm within the frame of the in-house-developed program to obtain the control valves' inherent flow characteristics which satisfy the linearity, and calculated the sensitivities of control valves with respect to the throttle angle. Also, we compared the obtained inherent flow characteristics with the existed data and concluded the results are satisfactory.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.585-589
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• 2010

It is important for the liquid rocket engine to meet the exact performance requirements in order to guarantee the successful mission of the launch vehicle. Usually, a ground combustion test for the engine is conducted to reduce the performance error and for the tuning. For the gas-generator (GG) cycle engine, this adjustment process can be easily tuned by means of the control valves. A linearized correlation between the process parameters of the control - the combustion chamber pressure and the mixture ratio of engine - and the independent parameter of the control- rotational angle of the control valve - could be suitable to reduce the tuning errors. Also this linearity can reduce the effort for the tuning and make the process more explicit by ensuring a more intuitive control. In this point, we proposed an algorithm in the frame of the in-house-developed program to obtain the control valves' inherent characteristics which satisfy the linearity.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.181-189
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• 2007

The technical requirements to the propellant of rocket engine using chemical energy are developed from the point of its performance, design and the exploration. The propellant, i.e. to get higher energy, to increase the cooling effect, and to be used in safety and comfort should be made. So from these aspect the technical requirements were written by the factors of physical chemistry. And the propellant combination used recently in Launch vehicles is liquid Oxygen and Kerosene, the main characteristics of this Kerosene as a fuel were reviewed. The toxicity and the safety of Kerosene, in specially, require the attention of the users. Also, it would be used in the development of Korean Kerosene by the comparative review of the several Kerosenes in Abroad.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.139-145
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• 2006

LRE(Liquid propellant Rocket Engine) is one of the important parts to control the trajectory and dynamics of rocket. The purpose of control of LRE is to control the thrust according to requiredthrust profile and control the mixture ratio of propellants fed into gas generator and combustor for constant mixture ratio. It is not easy to control thrust and mixture ratio of propellants since there are co-interferences among the components of LRE. In this study, the dynamic model of LRE was constructed and the dynamic characteristics were analyzed with control system as PID control and PID+Q-ILC(Iterative Learning Control with Quadratic Criterion) control. From the analysis, it could be observed that PID+Q-ILC control logic is more useful than standard PID control system for control of LRE.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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• pp.66-73
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• 2004

As a rocket propellent of hydrocarbon fuels, the characteristics of liquefied natural gas was evaluated with the viewpoint of the constituents and content, the cooling performance as a coolant, and characteristic velocity and specific impulse as parameters of the engine performance. Content of methane was a principal factor to determine the characteristics as a rocket propellant and more than 90% of it was needed as a fuel and coolant in the regenerative cooled liquid rocket engine. Some constituents of the liquefied natural gas can be frozen by the pre-cooling of the pipe lines, therefore they can be a factor disturbing the normal working of engine. In case the content of methane is around 90% in the liquefied natural gas, a normalized stoichiometric O/F mixture ratio of 0.75 is suggested for a nominal operation condition to get the maximum specific impulse and characteristic velocity.

• Current Industrial and Technological Trends in Aerospace
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• v.8 no.2
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• pp.86-97
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• 2010

This paper treats with the history and current trends in the developments of liquid-propellant rocket engine in Russia and Ukraine which are among world leaders in the technology of liquid rocket engine(LRE). In 1960s formerly the Soviet Union accepted the closed cycle engine for increasing the pressure in the combustion chamber and specific impulse to the maximum. However, since financially difficult times after 1990, they have decreased the cost for the development of new rocket engines. It was achieved by using existing units for new developed engines and minimizing the total number of engines and tests through the reasonable planning in the process for the experimental improvement of LRE. In addition, nowadays international cooperation in supplying LRE for commercial rocket and development of next generation LRE, such as 3 components engines and mathane engines, are proceeding.