• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.9
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• pp.76-81
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• 2006

This paper deals with a fuel metering unit (referred to as FMU) for air breathing engine. The proposed FMU consists of a constant pressure drop valve and a metering valve, both of which are controlled by servovalve. Linear analysis derived from a nonlinear mathematical model of FMU is carried out to find major parameters on the system performance. Numerical results using established model of FMU were in good agreement with the experimental results. It is also shown that the system stability is improved by reducing the constant pressure drop at metering valve and applying the triangular orifice to constant-pressure-drop valve through the simulation and experiments.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.2
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• pp.95-101
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• 2006

A fuel metering unit using PWM(Pulse Width Modulated) solenoid valve has some advantages such as low cost, small size and simple structure. The mathematical model and its experimental rig of the fuel metering unit using PWM solenoid valve and CPDV(Constant Pressure Drop Valve) for miniature turbo engines were constructed. As the results of simulation, some major parameters which have dominant effects on the performance were found. And the experimental results verified the validity of established model by showing the good agreement with the numerical simulation results. Hence, this system modeling could be used effectively in the actual development of a PWM fuel control system.

• Journal of the Korea Institute of Military Science and Technology
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• v.8 no.4 s.23
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• pp.152-158
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• 2005

In this paper, we have proposed a fuel metering unit of ai breathing engine. The proposed valve system consists of a constant pressure drop valve and a metering valve, which are controlled by servovalve. We carried out nonlinear and linear analysis, computer simulation and experimentation to find effects of some factors on system performance. Analysis and experimental results show a good agreement. It is also shown that the system stability is affected by pressure drop of metering valve and inlet pressure of injectors.

• Journal of the Korean Vacuum Society
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• v.15 no.6
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• pp.594-604
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• 2006

Gas fueling systems operated in the mode of a fixed valve opening at a constant line pressure, and the mode of a constant inlet flow are simulated to establish the relationships between the gas flow pattern and the tube dimensions under various system conditions.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.274-277
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• 2009

본 논문에서는 소형 PEM(Proton Exchange Membrane) 연료전지 스택의 BOS(Balance of Stack) 제어에 관하여 논의한다. 별도의 가습 장치가 필요치 않고 BOS의 구성이 비교적 간단한 소형 PEM 연료전지 시스템에서는 팬과 퍼지밸브만의 제어를 통해 스택 내부 수분의 조절과 열 관리가 수행된다. 따라서 본 논문에서는 부하에 따른 최적의 공기유량을 계산하고 요구되는 유량의 공급을 위해 팬을 제어하는 알고리즘을 통해 소형 연료전지 시스템의 과도응답 특성과 안정성을 향상시키는 방법에 관하여 제안한다. 150W급 소형 연료전지 시스템을 꾸미고, 마이크로컨트롤러를 이용한 제어회로를 구현하여 실험함으로써 제안된 알고리즘의 유용함을 검증하였다.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.1
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• pp.40-47
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• 2010

In this study, basic research on the thrust control by controling oxidizer mass flow rate of a $GO_2$/PE hybrid rocket is presented. For this purpose, hybrid rocket system including oxidizer flow control system and data acquisition system was developed. To control oxidizer mass flow rate, we used needle valve with stepping motor which was controled by LabVIEW program. During the fundamental experiments, this system managed to follow the pre-programmed (20 N - 10 N - 20 N - 0 N) thrust level.

• Plant Journal
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• v.10 no.3
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• pp.45-51
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• 2014

This study performs several experiments on a newly developed temperature safety system that can be used for residential building heating systems, the heat source of which is derived from a conventional fuel cell. Prior to this, the hot water made from a fuel cell was not used in residential housing but just went to waste. The present safety system is installed in the current underfloor heating system. At first we used the CFD technique to develop a new heat exchanger. The fuel cell must satisfy the thermal conditions of the inlet temperature being $55^{\circ}C$ and the outlet temperature being $60^{\circ}C$. But variations in weather cause fluctuations in the heating water temperature. The experimental results show our new system capable of maintaining the temperature difference within a ${\pm}0.5^{\circ}C$ range. So we believe that our new PFMFC fuel cell stack array is a good candidate for being used in residential heating systems.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.293-298
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• 2011

The combustion and flow-rate control characteristics of fuel-rich gas generator which could be adopted to Ducted Rocket propulsion system are investigated. The gas generator is designed considering the design requirements of propulsion system and solid fuel for fuel-rich combustion is developed then adopted to ground test. The results of combustion test show the necessity of the special analysis tool for estimating the gas generator performance where multi-phase flow of fuel-rich gas exists. During the flow-rate control test, characteristics of gas generator pressure with the angle of valve are analyzed and, method to estimate the pressure of gas generator is suggested using the relation between the valve exit area and discharge coefficient.

• 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 the Korean Institute of Gas
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• v.10 no.3 s.32
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• pp.1-6
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• 2006

This paper presents the applicability of low caloric synthetic gas from coal gasification to a gas engine system and small sized generator. A commercial LPG engine is modified to use the low caloric synthetic gas from coal gasification as the gas engine fuel. The modification is focused on the fuel supplying system, which includes air flowrate adjusting orifice, gas mixer, vaporizer, preheater, regulators, and fuel tank. From the results of engine performance data, we have demonstrated that the engine modified by using the coal gasification gas is well operated from idle to wide open throttle conditions although the engine power is somewhat reduced relative to LPG fueled engine. And we have also demonstrated that the generator is well operated with various loads.