• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.199-200
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• 2007

본 논문은 연료전지 발전시스템 승압용 다상부스트 컨버터의 입력전류리플 크기를 수식화 하고 통류율 범위에 따른 다상부스트 컨버터의 상수 설계기법에 대해 제안한다. 제안된 다상부스트 컨버터는 평균전류제어를 적용하였으며 일반적인 부스트컨버터와 입력전류리플크기, 출력전압리플 크기를 시뮬레이션을 통해 비교 측정하였다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1035_1036
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• 2009

본 논문에서는 연료전지에 적용될 수 있는 다상부스트의 동작과 전류 불연속 모드에서 입력전류의 발생 추이를 수식적으로 제시하였다. 제시한 방법은 입력전류의 구간을 나눈 뒤 구간마다 입력 전류의 상태 방정식을 각각 유도 하였으며 이를 바탕으로 리플크기를 나타내었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.251-253
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• 2017

Numerical study of air-blast type injector for low emission aircraft engines was conducted. Volume-of-fluids approach was used to track interface of fuel and air. Primary atomization of fuel stream was visualized, and thickness and mean velocity at the injector exit was calculated. Liquid fuel injected from fuel slots joined together as a thin film on preflimer surface, and interacted with swirling air. As instability on the fuel surface increased, separation of fuel as ligaments and droplets occured. The film thickness and velocity were used to as fuel injection boundary condition for reactive flow simulation. Primary reaction zone was formed in vicinity of the fuel nozzle, creating a stable flame inside the combustor.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.5
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• pp.67-72
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• 1997

The purpose of this study os to investigate how the natural gas in fuel blend influences the polutant emission of diesel engine. Four stroke cycle single cylinder engine is used for this experiment and four kind of fuel blends were made. Fuel blends show four different torque ratios between diesel oil and natural gas, which are 4 : 0. 3 : 1, 2 : 2 and 1 : 3. The constituents of exhaust gases of engine are analyzed for every fuel blend. The experimental results say that the mixing of natural gas into diesel fuel is an very effective way to reduce the amount of soot in the exhaust gas.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.8-8
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• 1998

액체 추진제를 사용하는 연소기관내의 연소 불안정 현상에 대하여 수치적인 해석을 수행하였다 비정상 다차원 다상 유동장에 대한 Eulerian-Lagrangian 방법에 기반을 두고 수학적으로 모델 하였으며 속도-압력-밀도에 대한 결합메커니즘은 개선된 PISO 알고리즘을 사용하여 처리하였다. 연소실의 기하학적 형상 및 추진제의 분무조건이 액체 연료 추진기관의 연소 불안정 현상에 미치는 영향을 체계적으로 해석하였으며 액체 추진제의 증발 특성이 연소 불안정 현상의 Driving Mechanism에 미치는 영향을 상세히 분석하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.745-749
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• 2011

Two-dimemsional liquid-solid multiphase fluid dynamics was used to analyze the suspension and mix of liquid fuel and solid particles in fuel tank installed mixing impeller. In this paper, the multiphase flow was modeled using Eulerian Grandular Multiphase model. Experimental measurements of the axial distribution of solids concentration in stirred tanks under 12vol% solid loading were used for comparison with the CFD simulation. Four cases for the impeller location and flow pumping direction also were reviewed under 10.5% solids loading and 700rpm in fuel mix tank. The result of quality of suspension was compared with each cases and the impeller location and operation of mixing fuel tank was established.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.329-331
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• 2008

기존의 발전용 연료전지 PCS 는 주로 DC-DC 컨버터 없이 인버터만 있는 방식이거나 3상의 DC-DC 컨버터에 인버터를 사용하는 방식이다. 본 논문에서는 발전용 연료전지 PCS의 부피저감과 고효율을 위한 DC-DC 컨버터의 최적 설계를 제안한다. 제안하는 DC-DC 컨버터는 DCM에 의한 소프트 스위칭으로 스위칭 주파수를 증가시킴과 동시에 상수를 증가시키는 방식으로 다상의 인터리빙으로 인해 필터 부피가 작아져 전체 PCS 효율을 높게 유지하면서 부피를 저감할 수 있다. 본 논문에서 PCS의 이론적 효율계산을 통해 DC-DC 컨버터의 최적 상수를 선정하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.375-378
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• 2011

The combustion characteristics of fuel-rich gas generator which could be adopted to Ducted Rocket propulsion system is investigated. The gas generator is designed considering the design requirements of propulsion system then solid fuel, which is developed by reducing the contents of oxidizer and increasing the contents of metallic solid particle, is loaded in the manufactured gas generator. The results of combustion test shows the necessity of the special analysis tool for estimating the gas generator performance where multi-phase flow of fuel-rich gas exists.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.1003-1011
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• 2008

In this paper, optimal design of interleaved boost converters is studied in order to design low ripple, size, loss and high performance converters for fuel cell applications. Also, the process of optimal design of interleaved boost converter has been performed. Input current ripple, output voltage ripple, losses and capacity of electrical components are theoretically analyzed and informative simulation and experimental results are provided.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.319-322
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• 2007

In the development of paralleling techniques, Multi-Phase Interleaved(MPI) converter constitutes one of the most promising alternatives reported in the last years. This technique consists of a phase shifting of the control signals of several cells in parallel operating at the same switching frequency. As a result, the aggregated input and output current waveform exhibit lower ripple amplitude and smaller harmonics content than in synchronous or stochastic operation modes. Based on the inherent advantages of the MPI converter, in this paper, a control scheme, which can reduce current and voltage rifle, is proposed for PEMFC generation systems. The MPI boost converter is composed of several identical boost converters connected in parallel.