• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.91.2-91.2
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• 2010

SOFC는 높은 반응온도($600{\sim}1000^{\circ}C$)에서 작동되어 발전효율이 높고 다양한 연료를 사용할 수 있는 것이 장점이다. 하지만 고온에서의 운전은 구성요소의 열변형과 온도구배에 의한 전극촉매의 열화 그리고 밀봉재의 수명에 영향을 주어 결국 스택의 내구성을 감소시킨다. 특히 스택의 온도구배가 심화되면 국부적인 Hot spot를 형성하여 셀에 심각한 손상을 주게 된다. 본 과제에서는 SOFC 스택의 온도구배를 완화시키기 위한 내부개질기의 개발 및 고온용 분리판 소재의 정밀성형기술을 확보하고자 한다. 열/유동해석을 통하여 반응가스의 농도, 유속, 구조변경 등 내부개질기 온도구배에 대한 주요인자를 확인하였고, 장기 운전평가를 통하여 개질 촉매의 고온 활성 및 내구성에 대한 성능평가를 진행 중이다. 분리판의 경우, 고온용 소재(페라이트계 스테인레스)에 대한 기초실험을 실시하여 성형품질의 주요 인자를 파악하였으며 Proto-type 금형 설계 및 개발을 통하여 성형 기초기술을 확보하였다. 그리고 스택 내부온도를 구현할 수 있는 시뮬레이터를 설계 중에 있으며 이를 이용하여 개발된 내부개질기 및 분리판을 스택 운전환경에서 평가할 예정이다.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.24-27
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• 2016

In this study, a 1kW Solid Oxide Fuel Cell(SOFC) test system was developed. A SOFC is the most promising power system to provide the higher efficient(over 50%) for house application area(1~10kW). To develop the optimized test system, the temperature control module that controls the preprocess and reaction condition, the flow control module that controls of the mass of reactants, and the electric loader that tests the discharge performance condition, etc. The temperature control module was designed to provide the high control resolution(under $1^{\circ}C$ at $750^{\circ}C$ of operating temperature) using K-type thermal couple. The flow control module was designed control blower and heater precisely using the phase control method. And the electric loader is designed that provide CV, CC, CR discharge mode and minimized the operating error adopting the independent DC-DC converter on analog input and output module. The performance of the developed SOFC test system showed that the accuracy of stack voltage was 0.15% at 80V and stack current was 0.1% at 100A.

• Proceedings of the SAREK Conference
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• 2005.06a
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• pp.223-223
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• 2005

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.53-56
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• 2005

Hybrid rocket had many advantage with compared to solid and liquid rockets. In this study, swirl flow hybrid motor was designed and manufactured. And the methods of regression rate improvement wire considered. Thrust was calculated with pressure of the combustion chamber and the regression rate was measured in low flow rate of oxidizer. Several problems and solutions of operating hybrid rocket was presented.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.311-317
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• 2005

Hybrid rocket had many advantage with compared to solid and liquid rockets. In this study, swirl flow hybrid motor was designed and manufactured. And the methods of regression rate improvement were considered. Thrust was calculated with pressure of the combustion chamber and the regression rate was measured in low flow rate of oxidizer. Several problems and solutions of operating hybrid rocket was presented.

• 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.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.2
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• pp.78-86
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• 2019

Aluminum, which is a metal fuel contained in the composite solid propellant, is not ignited and burned on the combustion surface by the oxide film, and it partially melts and coalesces with surrounding aluminum particles. For the evaluation and design of the propellant performance, modeling was performed to predict the size and distribution of agglomerated particles, and the size and distribution of agglomerates were compared and verified through experiment. The predicted values showed the tendency to decrease with pressure as in the experiment, but the error increased as the pressure increased. The agglomerated particle distribution graph showed a difference in the volume fraction although the diameter at the peak was the same.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.4
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• pp.52-60
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• 2015

Operation area of corps was expanded under military reformation, and extending range of 155 mm howitzer became important issue. New approach is needed to extend range to 80 kim. Ramjet engine is air breathing engine, and it can provide specific impulse several times more than solid rocket motor so that range is extended using same weight of propellant. If the ramjet engine is gun-launched system, it does not require any other booster because muzzle velocity is near Mach 3. Especially solid fuel ramjet (SFRJ) does not have any moving part so that it is favorable for gun-launching system which is under high stress during launching. In this paper, we design air intake, combustion chamber, and nozzle of 155 mm gun launched ramjet propelled artillery shell with inviscid flow assumption. We conduct parameter study to have range more than 80 km, and maximum high explosive volume.

• Journal of the Korean Society of Propulsion Engineers
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• v.18 no.4
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• pp.18-25
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• 2014

In this paper, the mechanism of the combustion instability which may occur in a hybrid rocket motor with a diaphragm was studied. And the new design for a hybrid motor grain was suggested. It could increase a regression rate of solid fuel, and reduce a large pressure oscillation in a hybrid rocket motor with a diaphragm. It was confirmed that the main mechanism of a large pressure oscillation was hole-tone, and it was caused by a collision between a diaphragm and a vortex which was generated in a pre-chamber. And 'Stepped Grain' design which had the mechanism for high regression rate in a motor with a diaphragm and could reduce a combustion instability was suggested.

• Clean Technology
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• v.17 no.1
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• pp.69-77
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• 2011

The intrinsic $CO_2$ separation and hydrogen production system is a novel concept using oxidation and reduction reactions of oxygen carrier for both $CO_2$ capture and high purity hydrogen production. The process consists of a fuel reactor (FR), a steam reactor (SR) and an air reactor (AR). The natural gas ($CH_4$) is oxidized to $CO_2$ and steam by the oxygen carrier in FR, whereas the steam is reduced to hydrogen by oxidation of the reduced oxygen carrier in SR. The oxygen carrier is fully oxidized by air in AR. In the present study, the chemical looping moving bed reactor having 200 L/h hydrogen production capacity is designed and the hydrodynamic properties were determined. Compared with other reactors, two moving bed reactors (FR, SR) were used to obtain high conversion and selectivity of the oxygen carrier. The desirable solid circulation rates are calculated to be in the range of $20{\sim}100kg/m^2s$ from the conceptual design. The solid circulation rate can be controlled by aeration in a loop-seal. To maintain the gas velocity in the moving beds (FR, SR) at the minimum fluidization velocity is found to be suitable for the stable operation. The solid holdup in moving beds decrease with increasing gas velocity and solid circulation rate.