• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.3
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• pp.219-226
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• 2014

A bus duct system for wind tower is introduced. A marine cable has been widely used in wind tower or various offshore structures. However, as the electric load capacity is increases, large number of cable lines must be used to cover the huge amount of electric capacities. Therefore, the installation of the cable lines becomes very difficult due to the heavy weight and volume of the cables. On the other hand, by using a single bus duct system line, the power capacity amount of 16 cables can be delivered with significantly compacted form. However, unlike flexible cables, the bus duct is relatively stiff which could generate the resonance phenomenon in the operating condition of the wind tower. In this study, the vibration characteristics of the bus duct are investigated and its long-term reliability during the life time of the wind tower is verified.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.495-500
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• 2001

Because of resonance between natural frequency of the second floor base for IPB(Isolated Phase Bus) duct supports in a power plant and operation frequency of the turbine, there was high amplitude vibration on IPB duct. To reduce vibration of IPB duct, Firstly it was set a FEM model to seek the mode shape for the concrete structure. Secondly, it was carried out dynamic analysis for the FEM model. Lastly, because the natural frequency of the concrete structure could not be changed, it was changed supports position for the IPB duct near to beams. It resulted in reducing vibration of IPB duct.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.223-233
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• 2002

The air distribution duct with multiple outlets is an essential part of automotive air-conditioning system In a bus. The estimation of airflow rate in an automotive air-conditioning duct is typically very complicate due to large variations in cross-sectional area and abrupt changes in flow direction, as well as unbalanced distribution of the flow. In this paper, the flow characteristic in a duct with multiple outlets is investigated through experiment, CFD simulation and a one-dimensional simulation. Numerical simulations have been performed for two simplified air conditioning ducts with multiple outlets used in a medium bus. The three dimensional Navier-Stokes code was used to evaluate the overall pressure, velocity Held, and distribution rate at each diffuser according to the change of various design parameters such as ratio of cross-sectional area and radius of bifurcated region. In addition, a one-dimensional program based on Bernoulli equation was developed to obtain optimized diffuser area required to equalize discharge flow rate at each outlet. As a result of this study, optimized diffuser area of design variable by one-dimensional program was very reasonable as compared to the trend deduced from CFD Simulation. Therefore, the simple and convenient one-dimensional analysis developed in this study can be applied in practical design procedure for air-conditioning duct.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2036-2041
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• 2014

In this paper, a thermal model is developed for the bus bar system to predict the temperature variation during the transient time period and to calculate both the steady-state and transient electrical current carrying capacity (ampacity) of bus bar. The bus bar system installed in the power house of Kumaraguru College of Technology, Coimbatore has been considered. Temperature variation predicted in the modelling is validated by observing the current and steady state temperatures in different feeders of the bus bar. Magnetic field of the extreme phases R and B induces more current in the middle phase Y. Hence, the steady state temperature in the phase Y is greater than other two phases. The transient capabilities of the bus bar are illustrated by calculating the variations in the bus bar temperature when it is subjected to a step change in current during the peak hours due to increase in hostel utilities and facilities (5.30 pm to 10.30 pm). The physical and geometrical properties of the bus bar and temperature variation in the bus bar are used to estimate the thermal time constants for common bus bar cross-sections. An analytical expression for the time constant of the bus bar is derived.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.16-21
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• 2005

The performance of reciprocating internal combustion engine is a strong function of the air intake system configuration. In order to improve engine power, it is essential to optimize the air induction system. In this study, a numerical investigation has been carried out for the three-dimensional flow and pressure characteristics in air intake system of a large-sized commercial bus. CFD simulations using STAR-CD were also perform ed to evaluate effects of intake duct geometry and structure variation inside air cleaner on the negative pressure distribution of overall intake system. Studies for improving the back pressure distribution have been proposed and quantitatively examined based on intensive case studies.

• Proceedings of the KIEE Conference
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• 2006.07e
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• pp.15-16
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• 2006

배전선로에 전력을 공급하는 방식은 일반적으로 22.9kV급 XLPE 케이블에 의한 전력공급이 주를 이루어 왔다. 한편으로 대규모 전력을 소비하는 공장 및 고층 빌딩의 전력 공급에 있어서는 일반적으로 각각 부하로의 많은 회선수의 케이블 포설을 요하는 전력케이블 보다는, 한 선로로 보다 많은 대전류를 수송하면서 부하 가까이에서 필요한 전류를 간편하게 분기해 공급받는 부스덕트 시스템이 시공 및 배전선로 관리의 간편성에 의해 점차 용도가 늘어나고 있다. 부스닥트 시스템의 대부분은 일단 시설물이 건축될 때 건축물의 상부 공간 또는 설비가 위치한 하부 바닥 구간을 통해 설치된 이후, 기타 배관, 가스관 등의 추가적인 건축 구조물과 함께 설치되어 이후 선로의 보수 진단 등이 대부분 어렵게 되어진다. 본 논문에서 소개하는 부스덕트의 온도감시 시스템은 아무리 복잡하고 협소한 설치 환경이라도 특수한 포설 공법에 의해 광화이버를 포설하고, 이를 활용하여 실시간으로 부스덕트 선로의 표면온도와 주변온도를 상시 감시함으로써, 효율적인 부스덕트 선로의 활용뿐만 아니라 과열에 의한 절연사고를 미연 방지하는 운전신뢰성과 안정성을 높이는 것이 가능하게 되었다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.610-616
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• 2020

This study conducted joint research with the Navy logistics command ship technology research institute to resolve the occurrence of naval vessel's high-temperature warning and equipment shutdown caused by VRTU overheating during summer operation and the dispatch of troops to equatorial regions. The cooling effect was checked according to the installation of a thermoelectric device cooling system, and heat flow and heat transfer characteristics inside VRTU was analyzed using Computational Fluid Dynamics. In addition, the temperature distribution inside the engine room was assessed through interpretation, and the optimal installation location to prevent VRTU overheating was identified. As a result, the average volume temperature inside the VRTU decreased by approximately 10 ℃ with the installation of the cooling system, and the fan installed in the cooling system made the heat circulation smooth, enhancing the cooling effect. The inside of the engine room showed a high-temperature distribution at the top of the engine room, and the end of the HVAC duct diffuser showed the lowest temperature distribution.