• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.354-358
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• 2009

Micro gas turbine engine is well known as a power plant of unmanned aerial vehicle and a small scale emergency generation system and also, it is significant as initial research of large gas turbine and educational purpose of gas turbine. Many sort of Micro gas turbine test set for education is produced by several manufacturers, but all of the engine control system of them is separated with data acquisition system; moreover, the engine control algorithms are inaccessible and related variables could not be collected. In this investigation, the Integrated Modifiable Test Rig which has modifiable engine start-up, drive and situational control logics is developed by LabVIEW with I/O devices and it provides wide experimental applicability to studies of dynamic characteristics of fuel system and combustion instability.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.3
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• pp.73-82
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• 2015

A high altitude test facility which includes supersonic diffuser and ejector has been developed to simulate atmospheric pressure at 25 km using a 500 N class small scale liquid rocket engine. Also high altitude simulation test for the small scale liquid rocket engine was performed to verify the facility's performance. The experimental facility consists of high altitude simulation device, propellants supply system and coolant supply system. Low pressure condition corresponding to about 27 km(0.021 bar) altitude atmosphere was successfully simulated and a small scale liquid rocket engine thrust level was confirmed at the simulated condition by the high altitude test facility verification test.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.321-324
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• 2011

A computational analysis of nozzle flow characteristics and plume structure using Reynolds-averaged Navier-Stokes equations with $k-{\omega}$ SST turbulence model was conducted to examine performance of the supersonic nozzle employed in a small liquid-rocket engine for ground firing test. Computed results and experimental outcome of 2-D converging-diverging nozzle flow were compared for verifying the computational capability as well as the turbulence model validity. Numerical computations of 2-D axisymmetric nozzle flow was carried out with the selected model. As a result, flow separation with backflow appeared around the nozzle exit. This investigation was reported as a background data for the optimal nozzle design of small liquid-propellant rocket engine for ground test.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.261-266
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• 2003

Foil air bearing, which is a noncontact bearing utilizing viscosity of operating fluid and elastic deformation of foil structure, has several advantages over rolling element bearings in terms of oilless environment, long life, high speed operation, and high temperature application over $500^{\circ}C$ . Recently advanced researches are actively being performed for the application to the extreme temperature such as gas turbines, as well as conventional small turbo machinery. In this paper, the principle of foil air bearing is introduced and a feasibility study to adopt a foil bearing as the turbine bearing of 65 HP turbo shaft engine, which is under development for UAV, is presented.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.192-195
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• 2008

A sensor fault detection method for small turbo shaft engine considering multiple trim conditions is proposed. This engine is used in a helicopter. Firstly, under multiple trim conditions, we derive the linearized models from a nonlinear model which includes engine, rotor and feedback control loop. As a fault detection method, we adopt the Kalman filter based method. To keep continuity of estimates between the changes of trim conditions, we reconfigure the initial values of state variables at trim changes. We detect the faults with two steps that when the first filter does not alarm the faults for some sensors, the second filter is runned for other sensor. Via some simulations we show that the proposed method works well under multiple trim conditions.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.85-92
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• 2020

Ground hot-firing tests were conducted to analyze the combustion performance according to the characteristic lengths 1.37 m, 1.71 m, and 2.06 m of the combustion chamber in 200 N-class GCH4-LOx small rocket engine. Thrust, specific impulse, and characteristic velocity at the steady-state could be obtained as the key performance parameters of the rocket engine. The performance characteristics acquired through the test were compared and analyzed with the theoretical performance calculated from CEA analysis. Observation of the influence of characteristic length on the combustion performance indicates that an optimal characteristic length shall remain between 1.71 m and 2.06 m.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.8
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• pp.791-796
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• 2012

Small gas turbine engines are used in aircraft as an auxiliary power unit (APU) to supply compressed air to start the main engine and for emergency electricity. When an aircraft is operating in an environment in which sand and dust is present in the ambient air, the engines as well as the APU ingest the sand and dust. This causes erosion of the engine and a degradation in its performance. The present study investigated the effect of sand and dust ingestion on small gas turbine engines. The concentration of sand and dust was $4.4{\times}10^{-5}kg$ per unit kg of air, which follows the specification in MIL-E-8593. The test was conducted for 10 h, and the engine performance before and after the test was compared. In addition, a tear-down inspection was conducted to examine the erosion patterns of sub-components such as the impeller and turbine wheel.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.28-33
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• 2020

In this study the possibility of hydrogen as a fuel in a small-sized two-stroke SI (Spark ignition) engine was investigated. For this purpose, experimental setup including an engine, a dynamometer, equipments for hydrogen and lubricant oil supply was prepared. And then preliminary experiments for the hydrogen-fueled engine combustion were conducted. In the case of hydrogen-fueled engines comparing to gasoline backfire occurs when the excess air ratio is lower than a specific value. This can cause engine power reduction and damage to the engine parts. The engine was controlled to operate at lean conditions to prevent backfire. Through the control of excess air ratio, the maximum engine brake power output of 3 kW was achieved in a 210 cc engine, while it was 6 kW in case of gasoline fuel.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.539-540
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• 2006

소형 열병합 (CHP, Combined Heat & Power)은 발전 용량이 1MW 이하인 발전 시스템을 지칭하는 용어로, 전기와 더불어 원동기에서 발생한 폐열을 회수하여 사용한 수 있는 발전 시스템을 말한다. 대표적인 원동기로서는 가스 엔진, 터빈, 마이크로 터빈, 연료 전지 등이 있다. 소형 열병합 시스템은 폐열 회수의 특징으로 기존 시스템에 비해 50% 이상의 에너지 이용 효율이 높으며, 기존의 대형 발전 시스템에서 필연적으로 존재하는 송전 및 배전 손실이 존재하지 않는 수요지 발전의 특징도 갖고 있어서 연료 절약형 에너지 생산 시스템으로서의 높은 가치를 가지고 있다. 또 다른 장점으로 열병합 발전 시스템은 여름철의 최대 전력 부하를 제거하는 역할을 할 수 있음으로 국가 전력 수요 공급의 안정화에 기여하는 바가 크다. 본 논문에서는 최근에 개발된 325kW급 열병합 가스엔진 발전 시스템의 주제어를 담당하는 통합 제어 장치의 개발과 소형 열병합 시스템의 시험 결과에 대해서 소개한다.

• Journal of Energy Engineering
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• v.14 no.3 s.43
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• pp.180-186
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• 2005

As an engine has a wide range of RPM $(3000\~12000\;RPM)$, variable control system is necessary in order to increase engine performance. SCV has been frequently referred to as a possible way to increase engine performance at low RPM. The purpose of this study is to investigate on the influence of SCV, specially at the range of lower revolution, in a high-speed small engine. Experiments were conducted on 4 Valves SOHC/air-cooling single cylinder engine and SCV shapes have been tested fur swirl intensity, the performance of power, fuel consumption and emission. As a result, we find to use SCV range be below 5000 RPM which fuel consumption decreased $9\%$.