• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.106-109
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• 2006

The purpose of this study is to analyze the installed performance of the PW206C turbo shaft engine used in the development of the smart UAV(Unmanned Ariel Vehicle) by KARI(Korean Aerospace Research Institute). It mainly aims to investigate performance behavior at installed conditions using both inlet and exhaust losses generated by CFD analysis of the ducts. The ways employed to be able to analyze the performance extensively were mainly rallied out by performing design point analysis of the engine where the performance simulation results from the commercial program 'GASTURB 9' used for simulation were used as inlet boundary condition for the ducts in CFD program The use of CFD tool involve modeling of the ducts to conform with the stipulated shape and sizes as defined by KARI with a grid density that allows reasonable flow characteristics applicable to aircraft components. Respective values of Shaft horse power obtained by varying flight Mach number, Gas generator RPM and Altitude considering several losses inclusive of those estimated by use of CFD tool were then plotted at three conditions with the ECS-OFF, ECS-MAX and at un-installed condition. Reasonable results were obtained as a result of using computational fluid dynamics that can hence be justified as an alternative tool for use in future flow analysis of engine and components.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1998.10a
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• pp.3-8
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• 1998

The industrial revolution in England was based on the manufacturing systems by the power of water mill and rapidly progressed by the innovation of steam engine. It is no exaggeration to say that today's civilization is realized by the development of various types of power machinery, namely fluid machinery and heat engine. The electric energy is converted mainly from thermal energy (mainly steam) of mineral oil, coal and nuclear fuel through generator connected with steam turbine which is a kind of power machinery. There are various types of power machinery as shown in Tables 1a and 1b. They are classified into two types by use. One is absorption type of fluid and/or thermal energy, for examples, windmill and heat engine. The other is provision type of the energies for examples, pump, compressor and propulsion. By flow type, they are also classified by two types, turbo type and positive-displacement type. The turbo type began from water mill and windmill and evolve to steam turbine and finally to gas turbine. The positive-displacement type started from reciprocating water pump and developed into steam engine and changed to reciprocating combustion engine. The pumps and motors used in oil hydraulic system for power control are also positive-displacement type.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.563-571
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• 2017

Test stand for altitude engine test of reciprocating engine was designed, manufactured and validated by preliminary test and simple calculation. These test stand designed to interface with Altitude turbo-shaft engine test facility of Korea Aerospace Research Institute. Many limiting condition for altitude test of reciprocating engine are assumed and test stand was developed to satisfy those limits. Test stand design specially focused on a altitude, Mach number and fuel temperature control for reciprocating engine altitude test with smaller air and fuel flow than turbo-shaft engine.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.12
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• pp.83-88
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• 2008

The QPP interleaver has been gaining attention since it provides contention-free interleaving functionality for high speed parallel turbo decoders. In this paper we first show that the quadratic term $f_2x^2%K$ of $f(x)=(f_1x+f_2x^2)%K$, the address generating function, is periodic. We then introduce a low-power address generator which utilizes this periodic characteristic. This generator follows the conventional method to generate the interleaving addresses and also to save the quadratic term values during the first half of the first period. The saved values are then reused for generating further interleaved addresses, resulting in reduced number of logical operations. Power consumption is reduced by 27.38% in the design with fixed-K and 5.54% in the design with unfixed-K on average for various values of K, when compared with the traditional designs.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.239-242
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• 1999

오존은 다른 산화제에 비해 산화력이 훨씬 높아 수처리에 많이 쓰인다. 본 논문에서는 오존 발생량, 오존 농도와 관계가 있는 주요 파라미터들의 손쉬운 제어를 위해 그래픽 사용자 인터페이스 모니터링 시스템을 구현하였다. 이 시스템은 Windows 98 환경의 PC에서 Turbo C와 LabVIEW를 사용하여 프로그램밍하며, 이 모니터링 시스템은 인버터를 제어하는 80196 Microprocessor와 양방향으로 통신한다. 본 연구에서는 모니터링 시스템이 가져야 할 오존 발생기 개발 단계에서 각 파라미터들의 최적값 결정과 오존 발생기 제조 단계에서 파라미터들의 조정이라는 두가지 목적에 적합하도록 그래픽 환경 사용자 인터페이스 구축에 그 초점을 맞추어 관리자가 효율적으로 오존 발생을 모니터링할 수 있게 한다.

• Journal of computational fluids engineering
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• v.1 no.1
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• pp.19-25
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• 1996

A multiblock grid generation has been developed to be reliably used for a Navier-Stokes simulation of the turbomachinery flow-fields A multiblock structure simplifies the creation of structured H-grids about complex turbomachinery geometries and facilitate the creation of a grid in the tip flow region. The numerical algorithm adopts the combination of the algebraic and elliptic method to create the internal grids efficiently and quickly. The grid refinement process is enhanced by developing strategies to utilized Bezier curves and splines along with weighted transfinite interpolation technique and by formulating the grid-imbedding method for the viscous boundary-layer meshes. For purposes of illustration, the grid generator is applied to the high turning turbine rotor blades. Two different types of computational grids are provided to be compared with respect to the grid adaptation to the flow simulations. Extension to three-dimensions was done to show the possibility of its application to the tip-flow simulations. The grid quality of the multiblock structure is good in the passages, with gloval orthogonality and adequate smoothness.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.1136-1140
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• 2001

Viscous fluid damper is used for vibration isolation of piping system, presses, turbo-generator and other heavy industrial equipments, as well as seismic isolation of buildings structure. So dynamic characteristic of viscous fluid damper is very important. This paper presents the result of the study of dynamic characteristic of viscous fluid damper. And the force-displacement relation of the viscous damper is described by experimentally calibrated fractional derivative Maxwell Model. The proposed model is validated by dynamic testing and A good agreement between predicted and experimental results is obtained.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.42-42
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• 2017

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.4
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• pp.407-416
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• 1991

A turbogenertor without damper cage is divided into five regions according to compoding materials in the radial direcrion. And the electric and magnetic field of each region in the subsynchronous resonance (SSR) phenomena is analyzed in this paper. The analytical method is based on solving a boundary value problem involving a three-dimensional magnetic diffrsion equation and the basic function consists of the double Fourier series. And the electrical characteristics of the material and kthickness of the wedges inserted in slot of the region III, which is dependent on frequency, is to be investigated.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1042-1044
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• 2003

High speed PM machines are being developed as motor/generators for gas-turbine generator sets in smaller power sizes, and as motors for number of applications including gas compressors, machine tools and turbo molecular pumps. Due to the high peripheral speed of the rotor and the relatively high conductivity of the magnets used, rotor eddy current loss can be substantial. This paper deals with the calculation of rotor eddy-current losse in permanent magnet(PM) high speed motor using the analysis of harmonics.