• Journal of the Korean Society of Propulsion Engineers
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• v.1 no.1
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• pp.24-32
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• 1997

A nonlinear dynamic simulation of a small gas turbine engine was performed by using DYNGEN program with various environmental conditions. It was observed that the effect of the bleed air flow rate changed to overall engine performance. The real time linear model which was a function of engine rotor speed was resulted to be close to nonlinear simulation results. For optimal LQR controller, it was considered only fuel flow rate or both fuel flow rate and bleed air rate as inputs. In the comparison of both results, the LQR controller with multi input had better performance than that with single input.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1997.04a
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• pp.55-60
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• 1997

A nonlinear dynamic simulation was performed by using DYNGEN program with various environmental conditions. It was observed that the effect of the bleed air flow rate changed to overall engine performance. The real time linear model which was a function of rpm was resulted to be close to nonlinear simulation results. For optimal LQR controller, it was considered only fuel flow rate or both fuel flow rate and bleed air rate as inputs. In the comparison of both results, the LQR controller with multi input had better performance than that with single input.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.6
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• pp.53-59
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• 2010

This research aims in finding a more optimal ejector size for evacuating engine exhaust gasses and 20% of the cell cooling air. The remaining 80% of cell cooling air pumped into the test chamber is separately exhausted from the test chamber via a discharge port fitted with flow control valves and vacuum pump. Unlike its predecessor this configuration utilizes a smaller capture area to improve pressure recovery. The modified ejector size has a diameter of 1100mm enough to evacuate 66kg/s jet engine exhaust in addition to about 20%, 24kg/s of the cell cooling air tapped from the sterling chamber. This configurations has an area ratio of the engine exit and ejector inlet of about 1.2. Simulation results of the proposed ejector configuration, indicates improved pressure recovery.

• Aerospace Engineering and Technology
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• v.9 no.2
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• pp.193-197
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• 2010

Water cooling ducts are installed in the exhaust diffuser for high altitude tests of rocket engine to protect diffuser from high-temperature combustion gas. The mass flow rate and pressure of cooling water is designed to prevent boiling of cooling water in the ducts. Therefore, the estimation of maximum temperature of duct wall is important parameter in design of cooling system, especially pressure of cooling water. The method for predicting maximum temperatures of duct walls with variation of coolant flow rates was derived theoretically.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.4-6
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• 2006

본 연구에서는 열차 추진 장치 시스템에 엔진의 중심부를 모의할 수 있는 Simplorer의 프로그램을 개발하여 M-G Set으로 모사한다. 열차의 엔진부와 발전기 구동에서의 제어는 DTC(Direct Torque Control) 제어로 모사 하였다. M-G Set을 구성은 견인력 토크지령을 받아 엔진부에서 DTC제어를 하였고, 발전기 구동 부는 속도지령을 받는 DTC제어로 하여 추진 장치 성능시험설비 열차운행모의에 의한 전력 조류 해석, 소비 및 회생전력을 분석할 수 있도록 하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.25-26
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• 2002

가스터빈 엔진의 성능모사는 개발단계에서의 개발위험도 감소나 개발비용 절감의 목적뿐만 아니라 운용단계에서 최적의 정비를 위한 엔진의 상태 진단을 위해서도 그 필요성이 매우 크다. 가스터빈 엔진의 성능모사를 위해서는 "각 구성품의 성능은 구성품 성능선도를 따라야 한다"는 제약조건을 만족해야 하며 이를 위해서는 구성품의 특성을 나타내는 성능선도가 매우 중요하다. 구성품 성능선도는 다양한 조건에서의 성능시험을 통해 얻는 것이 당연하나 이는 엔진 개발사에서나 가능하며 대부분 공개를 기피한다. 따라서 일반 구매자나 가스터빈 엔진의 성능을 연구하는 사람들은 일부 공개된 성능도를 축척하여 이용하고 있다.여 이용하고 있다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.239-242
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• 2004

In this paper, the general mathematical model of LRE(Liquid Rocket Engine) is presented. For the analysis about the trend of dynamics and the stability of open type LRE, it is transformed to linear model by Laplace transform and synthesized to the linear complex model of LRE with Matlab/Simulink.

• 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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• 2006.11a
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• pp.43-46
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• 2006

Storage air heater(SAH) is a general purpose facility that is used to simulate the high altitude condition of supersonic ground test facility, thurst compensation test of rocket engine nozzle and gas turbine engine combustor test. SAH in KARI is built to simulate the total temperature of the supersonic ground test facility which has a wide flight envelope from altitude 0km, Mach 2 to altitude 25km, Mach 5 and operates up to 1300K, 3.5MPa. In this paper, we introduces the SAH in JAXA which is model of SAH in KARI and summarizes the design process and manufacture of ours.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.37-37
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• 1998

중형항공기용 터보펜 엔진의 성능모사와 LQR 제어기 설계에 대한 연구를 수행하였다. 동적 성능모사를 설계점으로 선정한 지상최대이륙조건과 탈설계점으로 선정한 최대상승조건과 순항조건에 대하여 Step 증가, Ramp 증가, Ramp 감소, Step증가 후 Ramp 감소의 4가지 연료공급에 조건에 대하여 수행되었다. 성능모사 결과 모든 비행조건에서 연료를 Step 증가시킬 경우 고압터보빈의 입구온도가 제한온도인 3105$^{\circ}$R을 초과함을 확인하였고, 최대 상승조건에서 연료를 Step 증가시킬 경우가 4.5초 이내에 Ramp 증가시킬 경우 고압압축기에 서지가 발생함을 확인하였다. 따라서 고압터어빈의 오버슈트와 고압압축기의 서지를 동시에 제어할 수 있는 다변수 제어기의 설계가 필요함을 확인하였다.