• Journal of the Society of Naval Architects of Korea
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• v.46 no.5
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• pp.479-487
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• 2009

This paper describes the design of a full-spade twisted rudder section by using the genetic algorithm based on VLM(Vortex Lattice Method) and panel method. The developed propeller- rudder analysis program has been validated by comparing with experimental data. The developed code has been used for the design of a twisted full-spade rudder especially for finding out optimum section. The optimization has been firstly carried out by the genetic algorithm. The more detail variation of a rudder section has been also conducted by changing section profile in more detail to confirm the most optimum section profile. The developed new twisted rudder has been compared with existing twisted rudder by cavitation testing in the cavitation tunnel at MOERI. It is concluded that the developed twisted rudder has a lower cavity in comparison with existing twisted rudder. The verification of efficiency gain is expected to be carried out through self-propulsion tests in the near future.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.3
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• pp.11-20
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• 2000

The flow characteristics around the stern region of two VLCCs with the same forebody and slightly different afterbody are investigated along with propulsive performance of the ship. The local mean flow measurements and the resistance and self-propulsion tests are carried out in the towing tank for the two VLCC hull forms. The measured results clearly show the formation of bilge vortices and their effect on propulsive efficiency. The comparisons are made for the two VLCC hull forms and the relation between stern framelines and bilge vortex strength is explored. Experimental data can provide a good test case to validate the accuracy of numerical methods and turbulence model of CFD codes for ship flow calculation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.7
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• pp.552-560
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• 2014

Pulse Detonation Engine(PDE) has been investigated as a next generation propulsion system with the advantages of the higher thermal efficiency by the compression effect and the wide operation ranges from zero speed at ground. In the present study, an efficient theoretical PDE performance prediction program was developed for realistic propellants based on the Endo's theory combining the Chapman-Jouguet detonation theory and expansion process of burnt gas in a constant area tube. The program was validated through the comparison with the experimental data obtained by a ballistic pendulum measurement. PDE performance analyses were carried out for various hydrocarbon fuels and oxidizer compositions by changing the mixture equivalence ratio and initial conditions. Theoretical PDE performance database could be established as a result of the analyses.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.8
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• pp.713-721
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• 2014

In Europe and USA, new programs called GRC(Green Rotorcraft) and SRW (Subsonic Rotary Wing program) respectively, have been currently underway for developing the next generation rotorcraft. The final goal is to develope fuel-efficient/environmental-friendly tilt-rotor civilian rotorcraft, which can partly replace short-range regional aircrafts. Also for safe operation, the new rotorcraft technology is cooperated with the new air transport management(ATM) system, called SESAR(Single European Sky ATM Research) and NextGen(Next Generation Air Transport System) in Europe and USA. In addition to achieve the final goal, the tilt-rotor aircraft, they are trying to improve the performance of conventional helicopters by adopting more efficient propulsion system, active rotor system, and reducing internal and external noise. Especially in GRC program of Europe, the environmental factors such as noise, fuel efficiency, reduction of emission gas(CO2, NOx), are focused for the new technologies.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.8
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• pp.1080-1089
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• 2013

Interior Permanent Magnet Synchronous Machines (IPMSMs) with rare earth magnet are widely used in electric vehicles and hybrid electric vehicles. IPMSMs having high efficiency, high torque, and a wide speed range are employed in propulsion system. And the rotor in an IPMSM is generally made of a rare earth magnet to achieve a large energy product and high torque. This paper discusses issues regarding design and performance of IPMSMs using different factors of BH magnetic characteristic. It is necessary to choose factors of magnetic material according to permanent magnet shape in rotor for high performance. Response Surface Methodology (RSM) is selected to obtain factors of magnetic material according to variety of rotor shapes. The RSM is a collection of mathematical and statistical techniques useful for the analysis of problems in which a response of interest in influenced by several variables and the objective is to optimize response. Therefore, it is necessary to analyze the torque characteristics of an IPMSM having magnet BH hysteresis curve with different rotor shape. Factors of residual flux density (Br) factor and intrinsic coercive force (Hc) are important parameters in RSM for rotor shape. The rotor shapes for IPMSMs having magnet BH characteristic were investigated using the RSM, and three shapes were analyzed in detail using FEA. The results lead to design consequence of IPMSMs in the various rare earth magnet materials.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.196-200
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• 2004

A guard lamp system has been installed at the PV positive center, located at Gwangju in Korea. Digital environment that is represented to internet is displacing business way of industry and business achievement way with the fast speed being giving great change on life whole, improve existence business process utilizing internet and Web connection technology, information superhighway to tradition industrialist manufacture and e-transformation's propulsion that wish to maximize productivity and administration efficiency is spread vigorously. In this paper, we wish to accomplish generation equipment's heighten stability and believability through remote monitoring and control of guard lamp system. This paper describes the design of the monitoring system for the sensing data and indirect controlling of the guard lamp system. Most of the conventional monitoring systems depend on the special hardware and software. The essential design of monitoring system is to provide the convenience for the user and the portability for the system. In order for the system to fulfill its requirements, it was designed using Labview GUI facility based on the Windows 2000 environment of IBM PC compatible and Add-on card based on the TCP/IP protocol. Advantage of the monitoring system are a personnel expenses curtailment effect, of the place restriction and unmanned system of the generation plants, etc..

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.8
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• pp.1040-1049
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• 2010

The strengthened regulations for atmospheric emissions from ships have caused a necessity of new, alternative power system in ships for the low pollutant emissions and the high energy efficiency. Recently, new kinds of propulsion power system such as fuel cell system, which use hydrogen as an energy source, have been sincerely considered. The purpose of this work is to predict the performance of methanol fueled SOFC/GT hybrid power system and to analyze the influence of operating temperature of stack, current density of stack, pressure ratio of turbine, temperature effectiveness of recuperator, turbine inlet temperature.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.8
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• pp.849-854
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• 2013

Many researches on green ship with increasing on economics, efficiency and convenience have been carried out consistently. One of them is development of diesel engines with electronic control. While small duty one for automobiles had been adopted mainly already, disseminating heavy duty one for ships has trouble due to safety and reliability. In order to solve these problem in this study, performance of electronic control and cam type engine installed in parallel on training ship HANBADA of korea maritime university was analyzed and compared. It is certain that specific fuel oil consumption of the electronic control type is lower than cam type and excellent at lower engine load, especially. And the electronic control type shows more effective characteristic at sea trial on specific fuel oil consumption.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.10
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• pp.796-804
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• 2013

The "Potato Gun," a simple heat engine, is fabricated, tested and analyzed as a part of engineering education program of combustion and propulsion classes. Combustor pressure is predicted by the chemical equilibrium analysis of a constant volume combustor. Then, the internal ballistics, the conversion of thermal energy into the mechanical energy of a projectile, is predicted though the expansion process. The trajectory of a projectile is estimated by considering the aerodynamic effect around the spherical projectile. The energy conversion efficiency and the equivalence ratio of the fuel-air mixture could be estimated by the comparison of the experimental results and the theoretical prediction. The present work would be an example of attracting the interest of students for the application of the engineering principles at undergraduate level by recycling the waste materials.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.953-956
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• 2003

Digital environment that is represented to internet is displacing business way of industry and business achievement way with the fast speed being giving great change on life whole, improve existence business process utilizing internet and Web connection technology, information superhighway to tradition industrialist manufacture and e-transformation's propulsion that wish to maximize productivity and administration efficiency Is spread vigorously. In this paper, we wish to accomplish generation equipment's heighten stability and believability through remote monitoring and control of PV system. This paper describes the design of the monitoring system for sensing the monitoring data and indirect controlling of the PV system. Most of the conventional monitoring system depend on the special hardware and software. Basic design goal of monitoring system is to provide the convenience for the user and the portability for the system. In order for the system to fulfill its requirements, it was designed using Labview GUI facility based on the Windows 2000 environment of IBM PC compatible and Add-on card based on the TCP/IP protocol. Advantage of the monitoring system are a personnel expenses curtailment effect, free of the place restriction and unmanned system of the generation plants, etc..