• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.1
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• pp.84-89
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• 2011

A Xenon Feed System (XFS) has been developed for hall-effect thruster to small satellite space-propulsion system applications. The XFS delivers low pressure gas to the Anode and Cathode of thruster head unit from a xenon storage tank. Accurate throttling of the propellant mass flow rate is independently required for each channel of the thruster head unit. The mass flow rate to each channel is controlled using the accumulator tank pressure regulation through a micron orifice and isolation valve. This paper discusses the Xenon Feed System design including the component selections, performance estimation and functional test.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.5
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• pp.582-589
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• 2011

The fuel cell technology has been considered as a technology to reduce greenhouse gases emission from a ship. In this research, internal reforming 500kW solid oxide fuel cell system fueled by methane for a ship were developed. Characteristics of gas temperature, stack power and system efficiency depending on the air flow rate, $CH_4$ flow rate, $H_2O$ flow rate, and system operation pressure are evaluated. As a result, air and $CH_4$ flow rate directly affect the temperature of inlet and outlet gas in the fuel cell stack. When the air and $H_2O$ flow rate increase, the stack power and system efficiency increases. However, the case of $CH_4$ flow rate increase, the efficiency decreases.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.12
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• pp.1143-1150
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• 2007

The fuel transfer characteristics of the jet pump between fuel tanks, which is applied in the smart UAV fuel supply system, were experimentally investigated. The operating conditions of the jet pump were setup to meet the engine requirement according to mission profile, and the jet pump performance was evaluated at those conditions. The pressure ratio and the efficiency of the jet pump were measured with the variation of flow ratio. In addition, the area ratio was taken into the consideration to examine the effect on the jet pump performance. From the evaluation results, the jet pump met the fundamental requirement to transfer fuel with the flow ratio of 2.23. In the case of the jet pump that is focused on the fuel transfer quantity rather than its efficiency, the flow ratio would be adjusted through the variation of area ratio of the jet pump within the permitted limit of pressure ratio.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.4
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• pp.407-416
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• 2007

Fuel spray nozzle has a critical effect on combustion characteristics. Mass flow rate and SMD(sauter mean diameter) were selected as design variables by using the experiment data of various types of duplex fuel nozzles for the swirl atomizers. The sensitivity of each design variable on the mass flow rate and SMD was analyzed and the uniformity of mass flow rate was investigated through the shape optimization of duel-orifice-type swirl atomizers. The design variables that have a little effect on the optimum design were excluded using the DOE(design of experiments) method, which enabled the optimization of sensitive design variables on mass flow rate and limit tolerance. The SMD of the research spray nozzle that was used in this study was found to be most similar to that of the calculation results using the Jasuja's SMD relationship. This study showed the specific characteristics of duel orifice type swirl atomizers and the optimization of these kinds of nozzle. This study provided the optimization design of mass flow rate and its allowable tolerance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1677-1683
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• 2015

To cope with exhaust gas regulation, Diesel engine applied to electronic control system. As it accurately regulated the injected fuel mass and the fuel efficiency and the output are increased but the noise and the vibration are decreased. In order to keep the performance of Electronic Diesel Control System, it is important to accurately control the fuel pressure. However, when the regulator of fuel pressure is not controlled properly, the failure phenomenons(starting failure, staring delay, accelerated failure, engine mismatch et al.) occur because the fuel pressure is not stabilize. In this study, effects on a fuel pressure, engine rotating speed according to the control rate of fuel-pressure regulator are investigated in order to analyzed the performance variation with failure of fuel-pressure regulator. As a result, when the control rate of a fuel-pressure regulator is 4%~6% lower than that of standard condition, the variation of engine's rpm and return fuel flow is increased, and the abnormal condition was occurred. Besides, it is possible to diagnose the failures on fuel-pressure regulator under these conditions.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1832-1833
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• 2011

석탄연소 화력발전소 보일러의 최적 제어는 부하요구에 대하여 보일러 출력을 신속히 제어하고, 보일러 출력에 대하여 보일러 입력에너지인 석탄 유량을 조절하여 에너지 균형을 맞추는 것이다. 이는 안정된 부하뿐 아니라 부하변동시에도 균형을 유지하면서 제어해야 한다. 석탄 연소 보일러 에너지 입력이 되는 석탄유량 측정 및 보정은 유류나 가스연료보다 까다롭고, 석탄 연료의 발열량이 시간에 대하여 변하는 문제가 있으므로, 신속하고 안정된 제어 성능을 위해 계측된 석탄 유량을 설계기준치로 환산, 보정하여 제어해야 한다. 이에 대한 기술은 일찍이 보일러 출력인 증기 보유열량을 측정하여 실제 계측한 석탄 유량을 연속적으로 보정하는 기법을 사용하고 있다. 이에 대한 석탄 열량 보정 제어로직을 검토하여 최적 튜닝방안에 대하여 고찰하고자 한다.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.215-218
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• 2009

본 논문에서는 유량변화에 따른 200W급 PEMFC 운전특성을 연구하였다. 연료공급은 수소탱크와 공기공급용 컴프레셔를 이용하였고 유량은 MFC를 이용하여 제어하였다. 연료의 가습은 Bubbling type을 사용하였고 유량변화에 대한 반응차이를 크게 보기 위해 Back pressure 레귤레이터를 제거함으로써 확연한 차이를 얻을 수 있었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.368-372
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• 2005

The variation of regression rate of single port hybrid rocket was studied with various fuel. As fuel, PE, PMMA were used and gas oxygen as oxidizer. The regression rate depends on but flow rates of oxidizer also thermodynamic properties of fuel. In this study, the empirical relation for regression rate of solid fuel were found with mass transfer coefficient(B number) and oxidizer flow rate.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.307-311
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• 2008

Ground test of model Scramjet engine was performed with T4 free-piston shock tunnel at University of Queensland, Australia. Test condition of free stream was Mach 7.6 at 31 km altitude. With this condition, variation effects of fuel equivalence ratio, cavity, cowl setting were investigated. In the results, supersonic combustion or thermal choking was observed depending on the amount of fuel. Cavity and W-shape cowl showed early ignition and enhanced mixing respectively.

• Journal of the korean Society of Automotive Engineers
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• v.18 no.2
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• pp.18-28
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• 1996

메탄올이 자동차 연료로서 유망시 되고 있는 이유는 공급면과 이용면의 두 측면에서 장점을 가지고 있기 때문일 것이다. 공급면에 있어서는 원료가 천연가스나 석탄등 자원이 풍부하다는 점이 다른 연료에 비해 유리하며 특히 천연가스로 부터의 화학용 메탄올 제조기술이 거의 확립되어 있다는 점이다. 이용면에 있어서는 상온에서 운송, 저장 및 유량 제어 측면에서 취급이 비교적 용이하며 메탄올 연료의 특성상 옥탄가가 높고 희박연소한계가 넓어 고압축비 희박연소기관을 실현할 수 있으며, NOx나 매연 발생이 적은 저공해 연료인 점이 장점이다. 본 고에서는 본인의 실험실에서 이루어진 메탄올 연료에 대한 몇가지 실험결과들을 토대로 하여 메탄올 기관에 있어서의 일반적인 특성 및 문제점들에 대하여 소개하고자 한다.