• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.397-400
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• 2008

Traditional propellants which have a hypergolic characteristic have a high performance but also have disadvantages of toxicity and complex handling requirement. In order to replace these propellants, one of the alternatives is hydrogen peroxide which generates high temperature oxygen and water vapor after catalytic reaction. In this paper, autoignition characteristics of kerosene by decomposed hydrogen peroxide were investigated to perform fundamental research for designing a thruster using hydrogen peroxide and kerosene propellants. Contraction ratio, whether flame holder exists or not, and feeding pressure of propellants were selected as variables. From the experiments for different mixture ratio, we confirmed the ignition stability is strongly affected by a feeding pressure of propellants.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.403-404
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• 2008

The 2nd stage Kick Motor under the national aerospace middle and long term plan operates over the height of 300Km. Rocket Motors, designed for operation in high altitude, need nozzles with large expansion ratio to improve thrust efficiency. Hence, to evaluate the performance of such rocket motors on the ground, similar low pressure with the operating condition has to be made for the ground test to prevent flow separation in the nozzle. This study is for the installation of the high altitude test facility and test result for Kick Motor.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.32-32
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• 1998

고체 추진제 로켓의 연소시에 발생되는 산화 알루미늄(A1$_2$O$_3$) 입자는 로켓 추진 노즐에서 팽창과정의 효율을 저하시키는 요소가 되며, 이러한 비효율성은 연소 가스와 입자간의 비평형 상태 효과와 기본적인 속도와 열적 차이에 의해서 발생된다고 보고되었다. 또한 연소시 발생된 산화 알루미늄 입자는 높은 열과 큰 운동량을 가지고 로켓 노즐 내부를 유동하게 되며, 매우 많은 량이 짧은 시간에 고온 고속으로 노즐 벽면이나 기타 구조물에 충돌 및 점착하기 때문에 로켓 노즐내의 표면이 손상을 입게 되고, 로켓의 방향 제어 및 조정 안정성이 저하되며, 구조적인 강도가 약화 될 수 있다. 또한 산화 알루미늄 액적들의 경우 노즐 벽면에 고착되게 되면 로켓의 중량 증가로 인해서 추력의 손실을 초래할 수 있다. 따라서 이러한 연소 부산물들의 운동 경로와 충돌 위치 및 표면에서의 충돌량과 그리고 충돌에 따른 마모량 및 점착 그리고 열전달 특성을 예측하는 것이 필수적이다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.7
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• pp.703-711
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• 2008

In this paper, stabilizer which maintains the mixture ratio of gas generator of LRE has been introduced. Design criterion for the ideal performance of stabilizer was derived. Significant parameters on the performance of stabilizer were identified through mathematical model and gas generator system analysis. Also, simulation and test results of the gas generator system showed fair agreement, thus proving the validity of the mathematical model of the stabilizer.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.10
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• pp.118-126
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• 2004

The propulsive characteristics of oscillating flat plates are investigated using a discrete vortex method. The plates and their wakes are represented by discrete point vortices. To analyze the closely coupled aerodynamic interference between the plates, a vortex core model and a vortex core addition scheme are combined. A calculated wake shape for a flat plate in heaving oscillation is compared with flow visualization. The effect of wake shapes on the propulsive characteristics of the plates in pitching oscillation is investigated. The propulsive characteristics of oscillating plates with three cases (1. one is stationary and another is oscillating, 2. both oscillating in phase, 3. both oscillating out of phase) are calculated. The plates oscillating out of phase showed the largest thrust force among the three cases.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.1
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• pp.121-131
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• 1999

Automatic Rudder Trim System(ARTS) is a device to reduce the pilot's work load for rudder trimming greatly required in varying abruptly aircraft's engine power. This paper represents a technical analysis and a design of control law of the ARTS. The control law of the ARTS is designed based on the analysis of aircraft's characteristics, system's requirements, and limitations. The control law is comprised of open loop control using the rudder trim map for a specific aircraft and closed loop control to compensate the error of the open loop control system. flight test results show that the ARTS can reduce pilot's work load for rudder trimming dramatically and can compensate the aircraft's transient yaw motion.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.6
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• pp.889-895
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• 2011

PMLSM is structurally simple and it have a lot of merits such high speed, high thrust force etc., but cogging force by slot-teeth structure of armature and cogging force by outlet edge effect occurs. This is the cause of thrust force ripple and generate the noise and vibration. Therefore, in this paper we proposed installation of an auxiliary pole to mover of the PMLSM in order to decrease cogging force by the outlet edge which came necessarily into being discontinuous arrangement of the armature. Also, outlet edge cogging force designed a form of the auxiliary pole which the minimum became, and we compared a outlet edge cogging force characteristic along a winding method of an armature as we used 2-D of finite element analysis.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.5
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• pp.1-9
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• 2013

Variable area nozzle, where both throat and exit area vary, is required for optimal expansion and optimal nozzle shape upon operation of after-burner. Steady-state and transient analyses are carried out for each condition with and without afterburner operation and as a function of the location of the nozzle flap. Effects of that nozzle displacement on flow and thrust characteristics are analyzed from numerical results. With variable area nozzle adopted, the combustion field is variable in time, leading to periodically variable thrust. For off-design conditions, flow separation shows up due to over expansion at the flap tips and shock wave does in the nozzle due to under expansion. The undesirable phenomena can be solved by control of variable area nozzle.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.2
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• pp.10-18
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• 2010

Scramjet engine is one of the core parts of hypersonic vehicle of next generation and being investigated by many countries. Korea Aerospace Research Institute performed a ground test of the model scramjet engine S1 in 2007. And, S2 model which is improved from S1 model in engine startability and thrust was tested with HIEST (High Enthalpy Shock Tunnel) at Kakuda Space Center of JAXA. Design condition of S2 model was Mach 6.7, however, it was tested at Mach 7.7 as an off-design condition test. As a test result, flow separation was found at the inside of the intake, but the engine showed stable combustion pressure distribution. Furthermore, compared to other test models, S2 model showed a good performance value in thrust and specific impulse.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.6
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• pp.81-88
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• 2013

The component based propulsion modeling and simulation of an dual ramjet engine using Taylor-Maccoll flow equation and quasi 1-D combustor model. The subsonic and supersonic intake were modeled with Taylor-Maccoll flow having $25^{\circ}$ cone angle, the gas generator which transfers a pre-combustion gas into supersonic combustor was developed using Lumped model, and the determination of the size of nozzle throat of a gas generator was described. A quasi 1-D model was applied to model a supersonic combustor and the variation of temperature and pressure inside combustor were presented. Furthermore, the thrust and specific impulse applying fuel regulation by pressure recovery ratio and equivalence ratio were derived.