• Title/Summary/Keyword: 가스냉각

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Study on Cooling Characteristics of Mixed Gases with Hot Gas of Liquid Rocket Engine and Injected Liquid Nitrogen (액체로켓엔진의 연소가스와 액체질소 혼합에 의한 연소 가스 냉각 특성에 관한 연구)

  • Jeon, Jun-Su;Yu, I-Sang;Kim, Joong-Il;Kim, Jai-Ho;Ko, Young-Sung
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.36 no.10
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    • pp.1001-1009
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    • 2012
  • In this study, the cooling characteristics of combustion gas were investigated by injecting liquid nitrogen ($LN_2$) into a liquid rocket combustion chamber, which uses liquid oxygen (Lox) and kerosene as propellants. $LN_2$ injectors and an extended chamber for mixing were installed at the end of the ordinary LRE combustion chamber, and a nozzle was installed after the chamber for mixing. First, an ignition test of the liquid rocket engine was conducted to verify the stable combustion process. Next, a hot firing test was performed step-by-step for safety. Finally, the test was performed for 20 s. The results showed that the combustion gas of the LRE could be successfully cooled by using $LN_2$.

A Study on the Ship's ORC Power System using Seawater Temperature Difference (선박의 해수 온도차를 이용한 ORC 발전 시스템에 관한 연구)

  • Oh, Cheol;Song, Young-Uk
    • Journal of Navigation and Port Research
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    • v.36 no.5
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    • pp.349-355
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    • 2012
  • In this study, for the purpose of reduction of $CO_2$ gas emission and to increase recovery of waste heat from ships, the ORC(Organic Rankine Cycle) is investigated and offered for the conversion of temperature heat to electricity from waste heat energy from ships. Simulation is performed with waste heat from the exhaust gasse which is relatively high temperature and cooling sea water which is relatively low temperature from ships. The result shows that 1,000kW power generation is available from exhaust gas and 600kW power generation is available from sea water cooling system. Different fluid is used for simulation of the ORC system with variable temperature and flow condition and efficiency of system and output power is compared.

Preparation of Nickel Nanopowder using the Transferred Arc Plasma for MLCCs (이송식 아크 플라즈마를 이용한 MLCC용 니켈 나노분말의 합성)

  • Jung, Da-Woon;Oh, Seung-Min;Park, Dong-Wha
    • Korean Chemical Engineering Research
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    • v.46 no.4
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    • pp.701-706
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    • 2008
  • Nano-sized nickel powders were prepared by evaporating the bulk nickel metarial using transferred arc thermal plasma. Nitrogen gases are easily dissociated to atomic nitrogen in thermal plasma and they are quickly dissolved in molten nickel. Super-saturated atomic nitrogen in molten nickel is recombined to nitrogen gas because of the relatively low temperature of nickel surface. Generally, the recombine reaction of atomic nitrogen is exothermic, so bulk nickel is quickly evaporated to nickel vapor due to the thermal energy of recombine reaction. The particle size of nickel powder was controlled by $N_2$ used as the diluting gas. It was observed that as the diluting gas flow rate was increase, the particle size was decreased and the particle size distribution was narrowed. The average particle size at 250 l/min of the diluting gas was 202 nm analyzed by means of the particle size analyzer (PSA).

A Study on the safety measures for the protection of hydrogen cooling system of generator (수소를 냉각매체로 하는 발전기 안전대책에 관한 연구)

  • Lee Choon-Ha;Yuk Hyun-Dai
    • Journal of the Korean Institute of Gas
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    • v.8 no.4 s.25
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    • pp.55-61
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    • 2004
  • This paper provided a counter measures against the troubles and accidents that are likely to take place in the power plant using hydrogen gas as a coolant for the cooling system of the generator. Because of the extremely wide flammability limits of hydrogen in comparison to the other flammable gases, the safety measures against the hydrogen accidents is very important to ensure the normal operation of electric-power facility. This study's purpose was a presentation of standard model of safety management of hydrogen equipments in the coal firing power plant such as following items: 1) providing the technical prevention manual of the hydrogen explosions and hydrogen fires occurring in the cooling system of power generator; 2) the selection of explosion-proof equipments in terms of the risk level of operating environment; 3) the establishment of regulations and counter measures, such as the incorporation of gas leakage alarm device, for preventing the accidents from arising, 4) the establishment of safety management system to ensure the normal operation of the power plant.

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Performance analysis for load control of R744(carbon dioxide) transcritical refrigeration system using hot gas by-pass valve (핫가스 바이패스 밸브를 이용한 R744용 초임계 냉동사이클의 부하제어에 대한 성능 분석)

  • Roh, Geun-Sang;Son, Chang-Hyo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.9
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    • pp.2189-2194
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    • 2009
  • The automatic hot gas by-pass technique is applied to control the capacity of refrigeration and air-conditioning system when operating at part load. In the scheme, the hot gas from the compressor is extracted and injected into the outlet of an evaporator through a hot gas by-pass valve. Thus, In this paper, the hot gas by-pass scheme for CO2 is discussed and analyzed on the basis of mass and energy conservation law. A comparative study of the schemes is performed in terms of the coefficiency of performance (COP) and cooling capacity. The operating parameters considered in this study include compressor efficiency, superheating degree, outlet temperature of gas cooler and evaporating temperature in the R744 vapor compression cycle. The main results were summarized as follows : the superheating degree, outlet temperature and evaporating temperature of R744 vapor compression refrigeration system have an effect on the cooling capacity and COP of this system. With a thorough grasp of these effect, it is necessary to design the compression refrigeration cycle using R744.

Suggestion of Procurement Strategy with Commodity Classification by Peter Kraljic Matrix (피터 크랄직 매트릭스 기법에 의한 자재 분류를 활용한 구매 전략 제안)

  • Choi, Hyun Koo;Lee, Jae-Heon
    • Plant Journal
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    • v.11 no.3
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    • pp.53-63
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    • 2015
  • 구매자는 일반 제조업에서 자재를 피터 크랄직 매트릭스 기법에 의해 경쟁품목, 일반품목, 전략품목, 위험품목으로 분류한 후 각 품목 특성에 맞추어 구매 전략을 수립한다. 피터 클라직 매트릭스란 구매 리스크와 비즈니스 영향도 즉 특정 품목의 구매 금액 비중에 따라 자재를 분류하는 기법이다. 본 논문은 플랜트 엔지니어링산업에서 플랜트 기자재를 대상으로 피터 클라직 매트릭스 기법에 의해 기자재를 분류한 후 각 품목 특성에 맞는 구매 전략을 제안하고 사례 기업인 A사가 사우디아라비아에서 수행하는 발전 플랜트 기자재에 제안한 구매 전략을 적용하여 그 효과를 검증한 것이다. 플랜트 엔지니어링산업은 수주산업인데 총 수주금액 중 구매가 차지하는 비중은 약 50~60%이다. 따라서 프로젝트를 수행할 때 원가를 절감하여 이익을 극대화하기 위해 구매는 매우 중요한 역할을 한다. 플랜트 기자재는 크게 회전기계류, 고정장치류, 전기자재류, 제어자재류, 배관자재류로 구분된다. 각 공종별 플랜트 기자재에 대해 구매 지출 분석을 한 후 피터 클라직 매트릭스 기법에 의해 플랜트 기자재를 분류한 결과 경쟁품목에는 열교환기, 저장탱크 등이 포함되었고 일반품목에는 전선관, 조명기자재, 밸브 등이 포함되었다. 또한 전략품목에는 가스터빈, 가스터빈 흡입공기 냉각장치 등이 포함되었고, 위험품목에는 가스터빈 고정 볼트 등이 포함되었다. 경쟁품목 중 다관형 열교환기는 공급자와 공동으로 원가 모델을 구축하는 전략을 수립했고 저장탱크의 경우에는 공급자에게 원자재를 사급하는 전략을 수립하였다. 그 전략을 A사가 수행하는 프로젝트에 적용한 결과 각각 20%와 6%의 원가 절감 효과를 얻었다. 일반품목 중 전선관은 구매 대행사를 활용하는 전략을 수립했고 조명기자재는 기술 사양 검토 과정을 생략한 구매 프로세스 간소화 전략을 수립하였다. 그 결과 약 10%의 원가 절감과 평균 5일의 발주기간을 단축할 수 있었다. 전략품목 중 가스터빈 흡입공기 냉각장치는 공급자와 포괄적 양해각서를 체결하여 공동으로 사업주에 대응하는 전략을 수립했고 그 결과 프로젝트 수행 안정성 확보와 공급자 조기 참여를 통한 발주 스케줄 단축을 이룰 수 있었다. 위험품목 중 가스터빈 고정볼트는 재고 확보 전략을 수립하여 자재의 부족이나 파손으로 인해 프로젝트 공기에 영향을 주지 않도록 리스크를 감소시키는 효과를 얻었다.

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Effects of the Composition of Nitrogen Gas and the Working Pressure on the Temperature Distributions and Unit Cell Performance of MCFC (용융탄산염 연료전지의 양극가스내 질소 조성과 작동압력이 단위전지의 온도 분포 및 성능에 미치는 영향)

  • 김태진;안영주;주재백;정귀영;남석우;오인환;임태훈;홍성안
    • Journal of Energy Engineering
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    • v.4 no.3
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    • pp.354-363
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    • 1995
  • 차세대 연료전지인 용융탄산염 연료전지의 운전조건을 확립하기 위하여 운전변수와 단위전지 성능과의 관계를 살표보았다. 용융탄산염 연료전지에 산화제로 공기를 사용하는 경우 양극가스에 질소가 포함된다. 그리고 연료전지의 작동압력을 높이면 출력을 크게 할 수 있다. 그리하여 본 연구에서는 에너지 및 물질수지를 이용하여 양극가스내 질소 조성과 작동압력 변화에 따른 전지내의 온도분포 및 성능변화를 구하였다. 본 연구팀이 이미 발표한 용융탄산염 단위 연료전지의 전류밀도의 온도분포를 구하기 위한 수치모사가 이용되었다. 가스흐름의 형태는 십자류를 선택하였다. 양극가스내 질소의 영향은 냉각효과로 나타났다. 작동압력이 증가할수록 전지의 성능은 증가하였고, 기전력[mV]변화 대 압력[atm]의 상용대수값의 변화(즉, ΔV 대 Δ(log))의 1차함수 그래프 기울기는 79.9로 문헌상의 실험치와 유사하게 나타났다.

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Concept Design of 1700kN class LRE System using UDMH-LOX(I) (1700kN급 UDMH-LOX 계열 액체로켓엔진 시스템 개념설계(I))

  • Gostev V.A.;Lim SeokHee
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2004.10a
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    • pp.157-161
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    • 2004
  • The colse type of engine system, in which the combustion gas after the gas-turbine with high temperature is supplied to the combustion chamber, was selected to increase the energy characteristics in making the rocket engine scheme which makes 1700kN thrust. The nozzle was designed with consideration of film cooling, nozzle efficiency, and the real state of cobmustion gas during the expansion in nozzle. The change of gas state and the composition of the gas through the nozzle was studied by the graphic, too.

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Effect of the Recycling of Non-condensable Gases on the Process of Fast Pyrolysis for Palm Wastes (미응축가스 재순환에 따른 팜 부산물 급속열분해 반응 공정 특성)

  • Oh, Changho;Lee, Jang Hoon
    • Clean Technology
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    • v.24 no.3
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    • pp.233-238
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    • 2018
  • Bio-oil is produced by the fast quenching of hot vapor produced by fast pyrolysis of biomass in an inert atmosphere. Nitrogen is used as carrier gas to control the concentration of oxygen less than 3%. The consumption of nitrogen should be increased with increasing process size, and leading to increasing of facility and operating costs due to nitrogen charge. The effects of the recycling of non-condensable gases on the fast pyrolysis, bio-oil yield and quality, and nitrogen consumption have systematically investigated to see the possibility of these results in fast pyrolysis process of palm residue.

Development of Methane Gas Leak Detector Using Mid-infrared Ray Sensors with $3.2\;{\mu}m$ ($3.2\;{\mu}m$ 중적외선 센서를 이용한 메탄가스누출검지기의 개발)

  • Park, Gyou-Tae;Lyu, Keun-Jun;Han, Sang-In;Oh, Jeong-Seok;Kim, Ji-Yoon;Ahn, Sang-Guk;Yoon, Myung-Seop;Kwon, Jeong-Rock
    • Journal of the Korean Institute of Gas
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    • v.12 no.2
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    • pp.48-52
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    • 2008
  • According to extremely industrial growth, gas facilities, equipments and chemical plants are gradually increased due to incremental demands of annual amount of gases. The safety management of gases, however, is still far from their requirements. Methane, the principal ingredient of natural gas, is inflammable and explosive and is much used in factories and houses. Therefore, these gas safety management is essential. So, we, with a program of the gas safety management, hope to develop the detection system of methane gas leak using mid-infrared ray LED and PD with $3.2\;{\mu}m$. The cryogenic cooling device is indispensible at laser but needless at LED driven on the room temperature if manufacturing optical sensor with $3.2\;{\mu}m$. It, consequently, is not only possible to implement for subminiature and portable type but also able to speedily detect methane of extremely small quantities because the $CH_4$ absorption intensity at $3.2\;{\mu}m$ is stronger than that at $1.67\;{\mu}m$. Our objective of research is to prevent gas leak accidents from occurring previously and to minimize the extent of damage from them.

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