• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1176-1179
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• 2017

In this study, internal ballistic analysis theories of dual-thrust solid rocket motor using two kinds of propellant are found, and the theories are applied to develop internal ballistic analysis model. Internal ballistic analysis which is dual-thrust solid rocket motor using two kinds of propellant is carried out an applying of the random figures of two kinds of propellant and an analyze of the test results. Through this analytical model was able to an applying internal ballistic analysis for dual-thrust solid rocket motor using two kinds of propellant.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.245-248
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• 2011

A multi pulse rocket motor(MPRM) has several advantages compared to the single one. The range and the terminal velocity of the guided missile can be remarkably increased by the application of the pulse separation device(PSD) to the solid rocket motor which resulted in appropriate thrust distribution. In this study, the full scale heavy type dual pulse rocket motor with the bulkhead type PSD was designed, manufactured, and fire-tested. The bursting time and pressure of PSD were analyzed by the pressure, thrust and vibration results of static fire tests. As a result, the design requirement was verified that bursting pressure is lower than 30% of 2nd pulse operating pressure.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.213-216
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• 2008

U. S. and NATO allies have recently increased their emphasis on reducing the hazards of tactical munitions that contain energetic materials and actively started many investigations on Insensitive munitions(IM) of missile propulsion. All subcomponents of rocket motor should be properly designed and understood to increase IM properties. Insensitive propellant, motor case, ignitor and mitigation devices are important components of IM technologies of rocket motors.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1101-1102
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• 2006

In this paper, as a conceptual design of the catenary-current collection run tester which is planning to be constructed by KRRI, the feasibility study is described. In this study, reviews to determine the propulsion linear motor rating based on the target distance-speed curve through various simulation of LSM propulsion system were conducted. Moreover, the reviews of simulation results and desirable linear motor specifications are discussed in this paper.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2001.11a
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• pp.61-67
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• 2001

Hybrid propulsion systems provide many advantages in terms of stable operation and safety. However, classical hybrid rocket motors have lower fuel regression rate and combustion efficiency compared to solid propellant rocket motor. The recent research efforts are focused on the improvement of volume limitation and regression rate in the hybrid rocket engine. The present study has numerically investigated the combustion processes in the hybrid rocket engine. The turbulent combustion is represented by the eddy breakup model and Hiroyasu and Nagle and Strickland-Constable model are used for soot formation and soot oxidation. Radiative heat transfer is modeled by finite volume method. To reduce the uncertainties for convective heat transfer near solid fuel surface having strong blowing effect, the Low Reynolds number k-$\varepsilon$ turbulent model is employed. Based on numerical results, the detailed discussion has been made for the turbulent combustion processes in the vortex hybrid rocket engine.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.3
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• pp.778-784
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• 2017

This paper proposes a sensorless speed control of a permanent magnet synchronous motor (PMSM) based on an adaptive sliding mode observer (SMO) for electric propulsion system of small ships. An adaptive observer gain is proposed based on the Lyapunov's stability criterion to reduce the chattering problem at any speed operation instead of the constant gain observer. Furthermore, a cascade low-pass filter with variable cut-off frequency is suggested to strengthen the filtering capability of the observer. The experimental results from a 1.5 kW PMSM drive are provided to verify the effectiveness of the proposed adaptive SMO. The result shows that the proposed method gives good speed control performances even when the PMSM operates at 0.5% from its rated speed value.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.153-156
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• 2009

The pitch and yaw axis controls of Kick Motor, KLSV-I second propulsion system, was provided by the flexible seal that consists of alternate laminate of natural rubber and composite reinforcements between forward and aft ring. A hydrostatic actuating test has been conducted to evaluate a performance of the manufactured flexibke seal before it is assembled at the nozzle. Through the tests, we have verified an actuation torque and axial displacement of the flexible seal according to pressure variation. The actuation torque and axial displacement of all flexible seal is shown below 60kgf-m/deg at without pressure and 6mm at MEOP respectively.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.6
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• pp.85-91
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• 2012

This paper describes the results of study on reaction of insensitive igniter in which a pyrosensor is automatically sensing the rate of risk of fire or explosion of solid rocket motor exposed to an unexpected fire and makes the rocket motor burn itself safely. The Slow Cook Off(SCO) test following the regulation of MIL-STD-2105D was carried out with a rocket motor loaded with HTPB propellant, in which a thermal pyrosensor igniter was installed. The auto-ignition temperature measured was approximately $140^{\circ}C$ and it corresponded to Type V(Burning) reaction in SCO test, while the temperature by Kissinger equation was calculated to be $165.5^{\circ}C$.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1467-1472
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• 2014

This paper study on powering characteristic on speed variation of propulsion system of prototype 8200 electric locomotive propulsion system through simulation modeling. For this purpose, it being applied in the field of railway IGBT (Insulated Gate Bipolar Transistor) elements are used. Converter was performed PLL (Phase-Locked Loop) control method that is used to control the phase and output voltage, and the inverter was carried an indirect vector control method to control the speed of traction motor. The results of simulation by modeling and experimental unit, we was confirmed that converter is controlled a unity power factor and output voltage by reference voltage. Also traction motor was controlled by indirect vector control and SVPWM inverter switching method very well.

• International Journal of Railway
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• v.8 no.1
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• pp.15-20
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• 2015

As a result of the current population concentrations in urban centers, demand for intercity transportation is increasing rapidly. Railway transportation is becoming popular as an intercity transportation because of its timely service, travel speeds and transport efficiency. Among the many railway systems, the innovative and environmentally friendly maglev system has been rated very highly as the next-generation intercity railway system. Linear induction motors are widely used for the propulsion of maglev trains because of their light weight and low construction costs. The urban maglev that was recently completed in Incheon airport site employs a 110km/h class linear induction motor. However, this system was designed to meet requirements for inner-city operations and is not suitable as an intercity transportation system, which requires medium to high speeds. Therefore, this study deals with the characteristics and designs of linear induction motors used for the propulsion of maglev trains that can be used as intercity trains. Rail car specifications for high-speed trains have been presented, and the characteristics of linear induction motors that can be used for the propulsion of these trains have been derived using the finite element method (FEM).