• 한국추진공학회지
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• 제9권2호
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• pp.62-69
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• 2005

액체로켓 추진기관의 추진제 공급계 개발을 위한 추진제 탱크 가압시스템의 주요 변수들을 계산하는 설계방법이 본 논문에서 제시되었다 가압 유체의 공급 조건들이 추진제 탱크 내부에서 발생하는 열역학적 프로세스의 효율성에 미치는 영향을 분석하였고 이를 바탕으로 하여 추진제 탱크 입구에서의 가압 유체의 최적 공급온도, 공급 속도를 계산하였다.

• 에너지공학
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• 제6권1호
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• pp.104-113
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• 1997

본 연구에서는 상용공정모사기인 ASPEN PLUS를 이용하여 건식탄공급, 산소사용 분류층 가스화기인 Shell가스화공정, 저온가스정제공정, GE MS7001FA가스터빈, 삼압.자연순환식 폐열회수보일러, 재열복수식 증기터빈 및 극저온 산소분리공정을 채용한 IGCC시스템에 대하여 성능해석 모델을 개발하고 시스템 성능해석을 위한 민감도분석을 수행하였다. 본 모델의 적정성은 설계조건에서 대상탄을 이용한 정상상태 성능해석 결과를 타 시뮬레이션 결과와 비교함으로서 검증하였다.$^{1)}$ . Illinois#6탄을 대상으로 수행한 시뮬레이션 결과는 투입되는 탄에 함유된 수분의 양이 증가함에 따라 가스화기의 온도가 감소하며, 회분 및 황이 많은 경우에 현열손실이 증가하여 시스템 효율이 감소하였다. 개발된 모델을 이용하여 가스화기의 운전압력, 증기/석탄비율 및 산소/석탄비율에 따르는 시스템의 민감도분석을 수행한 결과 운전압력 증가에 따라 가스화기 노내온도가 상승하며, 가연성가스(CO＋H2) 생성율이 감소하였다. 증기/석탄비율 변화분석에서는 공급증기의 양을 변화시키면 가연성가스의 최고생성점이 보다 낮은 산소/석탄비율에서 나타남을 알 수 있었다. 또한 산소/석탄비율 변화분석에서는 증기/석탄 공급비율 0.2에서 산소/석탄 공급비율이 0.77인 경우에 가장 최적의 운전조건임을 알 수 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.131.1-131.1
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• 2010

This study was conducted for engineering optimization for the gasification process which is the key factor for success of Taean IGCC gasification plant which has been driven forward under the government support in order to expand to supply new and renewable energy and diminish the burden of the responsibility for the reduction of the green house gas emission. The gasification process consists of coal milling and drying, pressurization and feeding, gasification, quenching and HP syngas cooling, slag removal system, dry flyash removal system, wet scrubbing system, and primary water treatment system. The configuration optimization is essential for the high efficiency and the cost saving. For this purpose, it was designed to have syngas cooler to recover the sensible heat as much as possible from the hot syngas produced from the gasifier which is the dry-feeding and entrained bed slagging type and also applied with the oxygen combustion and the first stage cylindrical upward gas flow. The pressure condition inside of the gasifier is around 40~45Mpg and the temperature condition is up to $1500{\sim}1700^{\circ}C$. It was designed for about 70% out of fly ash to be drained out throughout the quenching water in the bottom part of the gasifier as a type of molten slag flowing down on the membrane wall and finally become a byproduct over the slag removal system. The flyash removal system to capture solid particulates is applied with HPHT ceramic candle filter to stand up against the high pressure and temperature. When it comes to the residual tiny particles after the flyash removal system, wet scurbbing system is applied to finally clean up the solids. The washed-up syngas through the wet scrubber will keep around $130{\sim}135^{\circ}C$, 40~42Mpg and 250 ppmv of hydrochloric acid(HCl) and hydrofluoric acid(HF) at maximum and it is turned over to the gas treatment system for removing toxic gases out of the syngas to comply with the conditions requested from the gas turbine. The result of this study will be utilized to the detailed engineering, procurement and manufacturing of equipments, and construction for the Taean IGCC plant and furthermore it is the baseline technology applicable for the poly-generation such as coal gasification(SNG) and liquefaction(CTL) to reinforce national energy security and create new business models.

• 한국분말재료학회지
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• 제13권6호
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• pp.396-400
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• 2006

The Ti-Ni alloy nanopowders were synthesized by a levitational gas condensation (LGC) by using a micron powder feeding system and their particulate properties were investigated by x-ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) method. The starting Ti and Ni micron powders $150{\mu}m$ were incorporated into the micron powder feeding system. An ingot type of the Ti-Ni ahoy was used as a seed material for the levitation and evaporation reactions. The collected powders were finally passivated by oxidation. The x-ray diffraction experiments have shown that the synthesized powders were completely alloyed with Ti and Ni and comprised of two different cubic and monoclinic crystalline phases. The TEM results showed that the produced powders were very fine and uniform with a spherical particle size of 18 to 32nm. The typical thickness of a passivated oxide layer on the particle surface was about 2 to 3 nm. The specific surface area of the Ti-Ni alloy nanopowders was $60m^2/g$ based on BET method.

• 한국기계가공학회지
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• 제11권6호
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• pp.152-157
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• 2012

This study investigates compressive strength of ice pellet strip which is potential medium for Natural Gas Hydrate(NGH) extruded from die holes of Twin-roll Press for Continuous Pelletizing(TPCP). Recently, the prototype of TPCP is newly developed where ice powder is continuously fed and extruded into strip-type pellet between twin rolls. The system is specifically designed for future expansion towards mass-production of ice pellet strips or solid form of natural gas hydrate. It is shown that the compressive strength of pellet strip heavily depends on factors in extrusion process such as disk size, surface smoothness, ring size, taper shape, feeding mechanism, and rotational speed. Here, the mechanism of TPCP, along with compressive strength of pellets is discussed in terms of its feasibility for producing NGH pellets in the future.

• 한국자동차공학회논문집
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• 제5권4호
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• pp.130-141
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• 1997

Work on the reduction of particulate matter(PM) from a diesel vehicl has led to a new trp system and a control method to control the combustion rate of the PM filtrated in the trap, which was named as 'Active Exhaust Feeding Regeneration(AEFR) System' by its operation mechanism. Ceramic cordierite filter is a major component of the trap and susceptible to thermal shock. Therefore the system should be designed to reduce the peak temperature and temperature gradients in the trap ; these have been considered to be the main factors causing thermal shock of the filter during the regeneration. It uses the engine's exhaust gas partially for the regeneration of the ceramic filter. It controlled bypass flow rate of the engine's exhaust gas precisely to control the temperature of the gas entrained into the filter. Gas temperatures were measured inside filter, and the oxygen concentration at the outlet of the filter was also monitored during the regeneration to analyze the combustion process of the PM. The temperature distributions and temperature gradients in the filter during the regeneration varied widely according to the regeneration control schemes. Finally, this system shows relatively low peak temperature and temperature gradients in the filter during its regeneration. It is considered that this system uses a mew method to control the combustion rate of the PM, which is different from the methods used in the previous studies.

• 한국추진공학회지
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• 제7권4호
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• pp.1-9
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• 2003

액체 로켓 시스템에 있어서 주 구조물과 연료 공급 장치의 상호작용 효과에 기인하여 발생하는 POGO라 불리는 축방향 동적 불안정 현상을 억제하기 위하여 몇 가지 종류의 PSD라 불리는 장치가 연구되고 있다. 본 연구에서는 기존에 사용된 PSD의 형태를 살펴보았다. PSD 장치는 수동적 PSD와 능동적 PSD 두 가지 그룹으로 분류할 수 있다. 수동적 PSD는 다시 컴플라이언스의 분포 방식에 따라 집중형과 분산형의 두 가지로 세분할 수 있다 현재까지 개발된 PSD 장치에 대한 포괄적인 검토를 통해, 기체 채움 수위조절 방식의 완충기가 연료 공급 장치의 성능을 저하시키지 않고 POGO 불안정성을 억제할 수 있는 최적의 PSD임을 잠정적으로 제안하였다.

• 반도체디스플레이기술학회지
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• 제5권1호
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• pp.27-31
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• 2006

Non-contact transportation system using air cushion for the manufacturing of large-sized LCD panels was considered. Flow characteristics between air pad and glass plate was analyzed using computational fluid dynamics method to obtain optimized air pad configurations. Effects of the design variables such as hole arrays from which gas is injected, gas-feeding method into the gas supplying channels, and horizontal and vertical pitches of clusters of holes were studied. Optimized air pad unit gave evenly distributed pressure contour on the glass surface and well-suspended levitation height in the experiment.

• 한국대기환경학회지
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• 제16권4호
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• pp.399-408
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• 2000

This study evaluated the SO2 adsorption characteristics using a continous moving bed system. Natural manganese oxide (NMO) reaction condition such as L/D the starting time of the NMO feed, feed rate, and flow rate of simulated flue gas, and NMO size were tested. The results showed that optimum L/D was 1.0 in this moving bed system. The higher the feeding rate was the higher the SO2 removal efficiency was and the higher the flow rate of simulated flue gas was the shorter the time to reach the euqilibirum concentration was. The final SO2 con-centration when it reaches the equilibrium concentration was not affected by the starting time of the NMO feed.

• International Journal of Aerospace System Engineering
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• 제2권2호
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• pp.1-5
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• 2015

The powder propellant rocket which uses micron-sized particles as fuel is storable and costly. Functions like thrust control and multiple-ignition can be realized by changing powder mass flow rate. In this paper, we discuss the theoretical performance of bi-propellant and mono-propellant powder rocket. When used as the fluidization gas, helium can improve specific impulse dramatically. The stability of the powder feeding device is preliminarily quantified through metal/N2O powder rocket hot fire tests.