• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2001.04a
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• pp.42-42
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• 2001

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.120-127
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• 2017

High temperature oxygen and water vapor was generated from catalytic decomposition of rocket grade highly concentrated hydrogen peroxide, and monopropellant thruster system was developed and applied into space propulsion system. In this research, background research and conceptual design of underwater propulsion system using catalytic decomposition of hydrogen peroxide was progressed. Two types of system was designed with different steam injection methods. Propulsion system that has ring-type steam injector was manufactured and performance estimation of system was performed with different nozzle exit area. Performance evaluation with central steam injection type jet engine will be progressed in the future.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.3
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• pp.337-345
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• 2015

High machining technology is needed for manufacturing jet engines for use in aircrafts. To reduce errors in the jet engine machining process, the machining companies of aircraft engines have introduced the CAM (computer-aided manufacturing) technology. However, to create a CAM model, the operator must manually conduct machining operations based on a CAD (computer-aided design) model, which can take several days or weeks. To solve this problem, this study proposes a method for automatically generating a CAM model for machining holes in the parts, using a CAD model. In this method, the features of the hole are recognized from the CAD model and translated into machining operations to be used with the CATIA program. Additionally, a prototype system was implemented and the proposed method was experimentally verified.

• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.1187-1193
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• 2011

In this paper, proposed controller preventing compressor surge and reducing the acceleration time of the fuel flow control system for turbo-jet engine. Turbo-jet engine controller is designed by applying fuzzy PID control algorithm and high-gain observer. Observer is used to estimate to compressor rotation speed of turbo-jet engine. Result of fuzzy inference is used as the fuel flow control inputs for preventing compressor surge and flame-out in turbo-jet engine. The controller is designed to converge to the desired speed quickly and safely. Using MATLAB to perform computer simulations verified the performance of the proposed controller.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.5
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• pp.118-126
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• 2002

The Altitude Engine Test Facility(AETF) was built at the Korea Aerospace Research Institute and has been being operated for the gas turbine engines in the class of 3,000 lbf thrust. To enhance the confidence level of AETF to the international level, a series of studies and facility modification have been conducted to improve the measurement uncertainty and reliability. In this paper, some part of the facility evaluation tests performed with a single spool turbojet engine are introduced. Tests were performed simulating the flight conditions as steady state, sea level for various flight speeds (i.e., Mn=0.3, 0.5, 0.7, 0.9). The obtained test results are compared with the predicted values of the engine DECK. The measurement uncertainties of airflow, net thrust, fuel flow and SFC showed 0.791~0.914%, 0.851~1.706%, 1.372~7.348% and 1.642~5.205%, respectively. Thus, from this research, the improvement methods of uncertainties on AETF has been confirmed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.1
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• pp.95-104
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• 2002

A two color PIV technique has been developed for visualization of complex and high speed flow in a ramjet combustor. Two color PIV has the advantages that velocity distribytions in high speed flowfields can be measured simply by varying the time interval between two different laser beams and a directional ambiguity problem can be solved by color separation, and then a singnal-to-noise ratio can be increased through nearly perfect cross-correlation. As a basic research of the ramjet engine, a 2-D shaped combustor with two symmetric air intakes has been manufactured and an experimental study has been conducted using a two color PIV technique. The flow characteristics such as recirculation zones and two intake air mixing have been investigated varying inlet angles and dome heights. It is found that the size and air mass ratio of reciculation zones are affected mainly by an inlet angle, but not much by a dome height.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.9
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• pp.629-641
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• 2019

In order to limit the temperature rise of the structure to a certain level or less while maintaining the aerodynamic shape of solid rocket nozzle by effectively blocking a large amount of heat introduced by the combustion gas of high temperature and high pressure, the heat-resistant materials such as C/C composite having excellent ablation resistance are applied to a position in contact with the combustion gas, and the heat-insulating materials having a low thermal diffusivity are applied to the backside thereof. SiC/SiC composite, which has excellent oxidation resistance, is applied to gas turbine engines and contributes to increase engine performance due to light weight and heat-resistant improvement. Scramjet, flying at hypersonic speed, has been studying the development of C/SiC structures using the endothermic fuel as a coolant because the intake air temperature is very high. In this paper, characteristics, application examples, and development trends of various heat-resistant composites used in solid rocket nozzles, gas turbine engines, and ramjet/scramjet propulsions were discussed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.4
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• pp.311-320
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• 2021

A study is performed for the real time fault diagnosis during operation and health estimation relating to performance deterioration in a turbojet engine used for an unmanned air vehicle. For this study the real time dynamic model is derived from the transient thermodynamic gas path analysis. For real fault conditions which are manipulated for the simulation, the detection techniques are applied such as Kalman filter and probabilistic decision-making approach based on statistical hypothesis test. Thereby the effectiveness is verified by showing good fault detection and isolation performances. For the health estimation with measurement parameters, it shows using an assumed performance degradation that the method by adaptive Kalman filter is feasible in practice for a condition based diagnosis and maintenance.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2000.11a
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• pp.13-13
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• 2000

램제트 엔진에 대한 기초 연구로서 양쪽 대칭의 공기 흡입구를 갖는 2차원 형태의 램제트엔진 연소기를 제작하여 그 특성을 분석하였다. 실험은 흡입공기의 연소실내 유입각도와 연소실내의 도움 위치에 따른 연소실 형상을 바꾸어가며 연소기내의 유동특성을 살펴보았다. 이를 위하여 고속 유동장의 2차원 평면 속도 분포를 측정할 수 있는 two color PIV 기법을 개발하였다. 이 기법은 다른 색의 두 레이저빔을 사용하여 방향성의 문제를 해결하며, 이미지의 색 분리에 따른 거의 완벽한 cross-correlation이 가능하며 높은 single-to-noise 비를 얻게 됨으로써 dynamic range의 증가가 가능해지며, 조사 영역 안에 존재해야 하는 입자 쌍의 수가 줄어들게 된다.(중략)

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.1
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• pp.45-51
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• 2018

The generation mechanism of NAR is not yet understood. In the present study, an in-depth analysis of the computational results previously obtained by the authors is conducted to investigate the flow mechanism responsible for NAR. A theoretical analysis has also been performed to understand the gas dynamic features during transition from scramjet to ramjet mode. It is known that there exists a critical value of the fuel equivalence ratio at which the flow states at the inlet of isolator remain unchanged. An increase in the equivalence ratio over the critical value leads to a sudden change in the static pressure and the Mach number at the inlet of the isolator, which is responsible for the generation of NAR.