• 제목/요약/키워드: Gaseous

검색결과 1,369건 처리시간 0.023초

Simple and Flexible Temperature Control System for Space Environment Test

  • Lee, Sang-Hoon;Cho, Hyok-Jin;Seo, Hee-Jun;Moon, Guee-Won;Choi, Seok-Weon
    • 한국우주과학회:학술대회논문집(한국우주과학회보)
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    • 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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    • pp.29.1-29.1
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    • 2008
  • The temperature control system which is using liquid and gaseous nitrogen has been known as the most economical system to simulate space temperature condition due to relatively not expansive price of the liquid nitrogen (less than 0.2 USD per liter). And, among these systems, the closed loop system which circulates compressed nitrogen gas come from sprayed liquid nitrogen by blower and makes a target temperature with heat from an electrical heater and flow rate of liquid nitrogen is prevail all over the world. But, this complete closed loop system requires expansive equipments such as blower, heater, and liquid nitrogen injector, and special maintenance on the system. Therefore, KARI is developing efficient and simple open loop system which utilizes liquid and gaseous nitrogen with eliminating a special blower and other expansive units. In this study, this open loop system with more efficiency and flexibility will be designed and introduced.

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수직 간섭된 램공기 대류에 의한 충돌 분무의 미립화 촉진에 관한 연구 (Spray characteristics of impinging sprays introduced into the strongly convective flow)

  • 이상승;윤웅섭
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2005년도 제25회 추계학술대회논문집
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    • pp.384-394
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    • 2005
  • Important characteristics of impinging sprays intersected by a strongly convective gaseous cross flows were experimentally investigated. The breakup processes due to different Weber and Reynolds numbers of liquid and gas streams were visually examined with quantitative measurements of breakup lengths, penetration heights, and droplet sizes. Snapshot images and spay data evidenced that, at lower jet Reynolds number the breakup processes portrays the atomization profiles similar to typical column breakup of single orifice jet. At higher jet Reynolds numbers, disintegration of jet stream is significantly expedited by strong momentum transported from strongly convective gaseous stream. The breakup length and penetration height decreased as the convective flow increase. From the bottom the wall up, the SMD measured the centerline increase. The maximum SMD appeared the top of the SMD distribution

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수직 간섭된 램공기 대류에 의한 스월 분무의 미립화 촉진에 관한 연구 (Spray characteristics of swirl sprays introduced into the strongly convective flow)

  • 이상승;윤웅섭
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2005년도 제25회 추계학술대회논문집
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    • pp.395-406
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    • 2005
  • Important characteristics of swirl sprays intersected by a strongly convective gaseous cross flows were experimentally investigated. The breakup processes due to different Weber and Reynolds numbers of liquid and gas streams were visually examined with quantitative measurements of breakup lengths, penetration heights, and droplet sizes. Snapshot images and spray data evidenced that, at lower jet Reynolds number the breakup processes portrays the atomization profiles similar to typical column breakup of single orifice jet. At higher jet Reynolds numbers, disintegration of jet stream is significantly expedited by strong momentum transported from strongly convective gaseous stream. The breakup length and penetration height decreased as the convective flow increase. From the bottom the wall up, the SMD measured the centerline first increases and then decreases before again increasing.

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압력섭동에 따른 비정상 화염편 응답특성 해석 (Flamelet Analysis for Transient Response to Pressure Oscillations)

  • 배준경;김용모;김성구
    • 한국연소학회지
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    • 제16권1호
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    • pp.30-35
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    • 2011
  • This study has been mainly motivated to numerically investigate the transient flame response to pressure oscillations in the gaseous hydrogen - liquid oxygen flames at supercritical pressures. The present analysis is based on the real-fluid transient flamlet model and the flame field is acoustically perturbed only by the sinewave oscillations in the frequency range from 1,000 Hz to 5,000 Hz. Based on numerical results, the detailed discussions are made for the flame response characteristics and the transient flamelet response associated with the high-frequency combustion instability in the liquid propellant rocket engines.

Gaseous by-products from the TiO2 Photocatalytic Oxidation of Benzene

  • Han, Sang-Wook;Lee, Jin-Hong;Kim, Jin-Seog;Oh, Sang-Hyub;Park, Young-Kwon;Kim, Hyun-Ook
    • Environmental Engineering Research
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    • 제13권1호
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    • pp.14-18
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    • 2008
  • Photocatalytic oxidations of benzene gas using the closed system (batch reactor) were induced to determine its by-products and investigate the effect of humidity and oxygen concentration on their generation. The study was able to identify 11 gaseous by-products: 2-methylpropene, acetaldehyde, acetone, pentane, methylcyclobutane, methylcyclopentane, cyclohexane, 2,3-dimethylbutane, 2-methylpentane, 3-methylpentane, and hexane. All the by-products were saturated hydrocarbons, which are less toxic than benzene and were probably formed through hydrogenation reaction on the photocatalytic surface. The photocatalytic oxidation of benzene under higher humidity produced less by-products. However, the amount of acetone released increased with higher humidity and oxygen concentration.

황해상 덕적도 PM2.5오염원의 확인 (Source Identification of PM2.5 at the Tokchok Island on the Yellow Sea)

  • 윤용석;배귀남;김동술;황인조;이승복;문길주
    • 한국대기환경학회지
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    • 제18권4호
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    • pp.317-325
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    • 2002
  • An air pollution monitoring station has been operated at Tokchok Island since April 1999 to characterize the background atmosphere in the vicinity of the Yellow Sea. In this study, eight chemical species in PM$_{2.5}$ and three gaseous species were analyzed. A total of 53 samples were collected for the analysis of PM$_{2.5}$ and gaseous species from April, 1999 to April, 2001. The overall mean mass concentration of PM$_{2.5}$ was 20.8 $\mu\textrm{g}$/㎥ and the eight soluble ionic species accounted for about 46.8% of PM$_{2.5}$ mass. Approximately 80% of samples appeared to experience the chloride loss effect. Air pollutant sources of PM$_{2.5}$ measured at Tokchok Island were qualitatively identified by the principal component analysis. It was found that five principal components are secondary aerosol, soil, incineration, phase change of nitrate, and ocean.and ocean.

소결 베드 연소 수치해석의 확장 - 가스 연료 주입 및 배가스 재순환 공정 적용 (Numerical Analysis of Sintering Bed Combustion; Applying Supplying Gaseous Fuel and Flue Gas Recirculation Processes)

  • 이영헌;양원;조병국;최상민
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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    • pp.9-13
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    • 2012
  • In the iron ore sinter process, temperature distribution pattern in sintering bed is related with productivity and quality of sintered ore. Evenly heat distribution make the uniform quality of sintered ore but in normal operating condition, upper part of bed has lack of heat and scarce quality of sintered ore, thus yeild rate is decreased and productivity is diminished. Therefore, using the additional fuel for increasing quality and flue gas recirculation for increasing productivity are considered and effect of both processes are discussed.

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탄소성 금속관 내 가스 폭굉의 수치적 연구 (Numerical investigation of gaseous detonation observed in the elasto-plastic metal tubes)

  • 곽민철;도영대;박정수;여재익
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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    • pp.85-87
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    • 2012
  • We present a numerical investigation on gaseous (ethylene-air mixture) detonation in the elastoplastical metal tubes to understand the wall effects associated with the developing detonation instability. The acoustic disturbances originating from the rapidly expanding tube walls reach the detonating flame surface, thereby causing flame distortions and total energy losses. The compressible Navier-Stokes equations with equation of state for gas and elasto-plastic deformation field equations for inert tubes are solved simultaneously to understand the complex multi-material interaction in the rapidly expanding gas pipe. In order to track governing variables across the material interface, we use the hybrid particle level-set and ghost fluid methods to precisely estimate the interfacial quantities. Features observed from the deforming (thin) tube show substantially different behavior when a detonation propagates in the rigid (thick) tube with no acoustically responding wall conditions.

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Development of SPR Gas Sensor for Small Molecules Using Molecularly Imprinted Polymer Thin Films

  • 장성우;진성일;박찬량
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2011년도 춘계학술발표대회
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    • pp.242.2-242.2
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    • 2011
  • Molecularly imprinted polymer thin films were applied to develop a gas sensor based on the surface plasmon resonance phenomenon for small gaseous molecules such as toluene and xylene. The imprinted polymer films were synthesized via photo-polymerization method using various combination of templates, functional monomers and cross-linkers. The temperature of pre-polymerization solutions and the power of UV light were controlled for optimized performance of gas sensing. The morphology and porosity of the polymer films were controlled by varying the mixing ratios of the pre-polymerization solutions and confirmed by atomic force microscopy. By fitting the adsorption/desorption sensorgrams to conventional kinetic models, the effects of different templates and cross-linkers were interpreted in term of the structural differences of the polymer networks formed on the gold film. The sensitivity and selectivity of sensors were estimated for toluene and xylene, and also for humidity and other gaseous molecules such as formaldehyde and ammonia.

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低質炭의 利用硏究 (第一報) 無燃固體燃料의 燃燒速度의 測定) (Studies on the Utilization of Low Quality Coals (1) Determination of combustion velocity of smokeless solid fuels)

  • 오신섭;김정혁
    • 대한화학회지
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    • 제4권1호
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    • pp.78-80
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    • 1957
  • Up to now, only superficial studies on the combustion velocity of smokeless fuels have been reported, while it should be a basical factor on the utilization of low quality coals and some other smokeless solid fuels. It was, therefore, difficult to choose raw material coals in manufacturing gaseous fuels. With the intent to solve above problem, we have determined combustion velocity of domestic anthracites, graphites, coalites of lignite and cokes from Japanese bituminous coal. The results show that the cokes from Japanese bituminous coal which has been used as raw material in the manufacturing gaseous fuels such as water gas, or producer gas in Korea can be replaced by some sources of domestic anthracite or coalite of lignite.

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