• 제목/요약/키워드: stage combustion

검색결과 321건 처리시간 0.029초

한국형발사체 3단 터빈배기부 개념설계 (Conceptual Design of Turbine Exhaust System for 3rd stage of Launch Vehicle)

  • 신동순;김경석;한상엽;방정석;김현웅;조동혁
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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    • pp.1068-1071
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    • 2017
  • 3단 터빈배기부 구성은 터빈 플랜지, 열교환기, 배기덕트와 추력노즐로 이루어진다. 냉가스 가압 방식에 비하여 열교환기 가압 방식을 사용함으로서 추진제탱크 가압을 위한 헬륨가스 자체 무게와 저장 탱크 무게가 감소하는 장점이 있기 때문에 발사체에 열교환기를 사용한다. 가스발생기는 추진제 연료과농 조건에서 연소가 이루어지며, 연소가스 중에 그을음이 많이 포함되어 있기 때문에 열교환 효율이 감소하는 것을 고려하여 열교환기를 설계해야 한다. 본 논문에서는 터빈배기부 구성품 배치, 열교환기 내부 구조 및 제작성을 고려한 설계기법, 기 설계된 노즐 설계를 바탕으로 3단 터빈배기부 재 노즐 설계 형상에 대한 장점을 기술하였다.

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3-Dimensional Analysis of the Steam-Hydrogen Behavior from a Small Break Loss of Coolant Accident in the APR1400 Containment

  • Kim Jongtae;Hong Seong-Wan;Kim Sang-Baik;Kim Hee-Dong;Lee Unjang;Royl P.;Travis J. R.
    • Nuclear Engineering and Technology
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    • 제36권1호
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    • pp.24-35
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    • 2004
  • In order to analyze the hydrogen distribution during a severe accident in the APR1400 containment, GASFLOW II was used. For the APR1400 NPP, a hydrogen mitigation system is considered from the design stage, but a fully time-dependent, three-dimensional analysis has not been performed yet. In this study GASFLOW code II is used for the three-dimensional analysis. The first step to analysis involving hydrogen behavior in a full containment with the GASLOW code is to generate a realistic geometry model, which includes nodalization and modeling of the internal structures such as walls, ceilings and equipment. Geometry modeling of the APR1400 is conducted using GUI program by overlapping the containment cut drawings in a graphical file format on the mesh view. The total number of mesh cells generated is 49,476. And the calculated free volume of the APR1400 containment by GASFLOW is almost the same as the value from the GOTHIC modeling. A hypothetical SB-LOCA scenario beyond design base accident was selected to analyze the hydrogen behavior with the hydrogen mitigation system. The source of hydrogen and steam for the GASFLOW II analysis is obtained from a MAAP calculation. Combustion pressure and temperature load possibilities within the compartments used in the GOTHIC analysis are studied based on the Sigma-Lambda criteria. Finally the effectiveness of HMS installed in the APR1400 containment is evaluated from the point of severe accident management

STUDY OF CORRELATION BETWEEN WETTED FUEL FOOTPRINTS ON COMBUSTION CHAMBER WALLS AND UBHC IN ENGINE START PROCESSES

  • KIM H.;YOON S.;LAI M.-C.
    • International Journal of Automotive Technology
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    • 제6권5호
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    • pp.437-444
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    • 2005
  • Unburned hydrocarbon (UBHC) emissions from gasoline engines remain a primary engineering research and development concern due to stricter emission regulations. Gasoline engines produce more UBHC emissions during cold start and warm-up than during any other stage of operation, because of insufficient fuel-air mixing, particularly in view of the additional fuel enrichment used for early starting. Impingement of fuel droplets on the cylinder wall is a major source of UBHC and a concern for oil dilution. This paper describes an experimental study that was carried out to investigate the distribution and 'footprint' of fuel droplets impinging on the cylinder wall during the intake stroke under engine starting conditions. Injectors having different targeting and atomization characteristics were used in a 4-Valve engine with optical access to the intake port and combustion chamber. The spray and targeting performance were characterized using high-speed visualization and Phase Doppler Interferometry techniques. The fuel droplets impinging on the port, cylinder wall and piston top were characterized using a color imaging technique during simulated engine start-up from room temperature. Highly absorbent filter paper was placed around the circumference of the cylinder liner and on the piston top to collect fuel droplets during the intake strokes. A small amount of colored dye, which dissolves completely in gasoline, was used as the tracer. Color density on the paper, which is correlated with the amount of fuel deposited and its distribution on the cylinder wall, was measured using image analysis. The results show that by comparing the locations of the wetted footprints and their color intensities, the influence of fuel injection and engine conditions can be qualitatively and quantitatively examined. Fast FID measurements of UBHC were also performed on the engine for correlation to the mixture formation results.

The Bioenergy Conversion Characteristics of Feedlot Manure Discharging from Beef Cattle Barn

  • Oh, Seung-Yong;Kim, Chang-Hyun;Yoon, Young-Man
    • 한국토양비료학회지
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    • 제48권6호
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    • pp.697-704
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    • 2015
  • This study was carried out to assess bioenergy conversion efficiency by biogas and solid fuel production in the cattle feedlot manure discharged from beef cattle barn. Feedlot manure was sampled from the cattle farmhouse located in Yong-in, Gyeonggi during the mid-fattening stage, periodically. The chemical characteristics, BMP (Biochemical methane potential) and HV (Heating values) of feedlot cattle manures were analyzed. Total solid contents of cattle feedlot manure were in the range of 29.98~44.28%, and volatile solid contents were in the range of 23.53~24.47%. In the anaerobic digestion of cattle feedlot manure, the methane production potential has increased from 0.141 to $0.187Nm^3kg^{-1}-VS_{added}$. The methane production of fresh cattle feedlot manure showed the range $0.141{\sim}0.187Nm^3kg^{-1}$-Manure (average $0.047Nm^3kg^{-1}$-Manure), the LHVs (lower heating values) of the produced methane were in the range of $316{\sim}560kcalkg^{-1}$-Manure (average $400kcalkg^{-1}$-Manure). In the direct combustion of fresh cattle feedlot manure, the LHVs were measured in the range of $747{\sim}1,271kcalkg^{-1}$-Manure (average $916kcalkg^{-1}$-Manure), and LHVs of solid fuel which have the water content of 20% were in the range of $2,694{\sim}2,876kcalkg^{-1}$-Manure (average $2,791kcalkg^{-1}$-Manure). Then, the drying energy of average $443kcalkg^{-1}$-Manure was consumed in the production of solid fuel which has a water content of 20%. Therefore, the direct combustion of cattle feedlot manure showed about 2.3 times higher LHV than the LHV of methane produced by anaerobic digestion. And LHV of solid fuel was about 6.0 times higher than the LHV of methane produced by anaerobic digestion. Then, the production of solid fuel presented more bioenergy conversion efficiency than the biogas production in the bioenergy use of cattle feedlot manure.

자동차용 연료전지 냉각계통 열관리 동적 모사 (Dynamic Modeling of Cooling System Thermal Management for Automotive PEMFC Application)

  • 한재영;이강훈;유상석
    • 대한기계학회논문집B
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    • 제36권12호
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    • pp.1185-1192
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    • 2012
  • 차량용 연료전지는 내연기관보다 운전 온도가 낮아 냉각수의 온도를 낮게 관리해야 하며, 이러한 냉각수 온도는 대기와의 온도차가 내연기관보다 작아 고성능 방열판 및 열관리계가 요구된다. 이러한 차량용 연료전지 열 관리계는 특히 연료전지 운전 온도 및 스택 내 온도분포를 결정하는 중요한 구성품이다. 본 연구에서는 차량용 연료전지 열 관리계 모델을 Matlab/$Simulink^{(R)}$ 환경 하에 개발하였으며, 기본 설계에 적용이 가능하도록 방열판 상세 모델을 개발하고 열 관리계는 팬, 모터, 방열판 그리고 냉각수 펌프로 구성하였다. 팬과 펌프는 경험식을 이용해 모델을 개발하였으며 모터 동특성을 고려하였다. 두 구성품은 연료전지의 입구와 출구 온도를 추출해 정해진 지령을 수령하도록 제어 하였다. 본 연구에는 연료전지 차량에 적합한 방열기 설계를 위해 방열기 특성을 확인하고, 이를 연료전지 시스템과 통합운전하면서, 연료전지 운전제어에 적절한 지 확인하였다.

소형발사체 상단용 액체메탄 로켓엔진의 개념설계 (Conceptual Design of a LOX/Methane Rocket Engine for a Small Launcher Upper Stage)

  • 김철웅;임병직;이준성;서대반;임석희;이금오;이기주;박재성
    • 한국추진공학회지
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    • 제26권4호
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    • pp.54-63
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    • 2022
  • 500 kg의 페이로드를 500 km 태양동기궤도에 이송가능한 소형발사체의 상단에 사용될 3톤급 액체로켓엔진을 설계하고 있다. 소형발사체의 1단에는 비행시험으로 검증된 75톤급 엔진을 사용한다. 상단용 엔진은 액체산소와 액체메탄을 연료로 사용되는데, 이 추진제 조합은 공통격벽탱크를 적용하여 무게 감소가 가능하고 비추력도 높다. 상단엔진의 사이클로는 저압으로 운용되어 신뢰성이 높은 팽창식 사이클을 채택했으며, 노즐 확대비 120이상에서 360초를 상회하는 비추력 성능을 보일 것으로 평가되었다. 엔진의 주요구성품인 연소기와 터보펌프는 목표 비용을 맞추기 위하여 적층제조된다. 엔진은 자가증기가압과 롤추력제어를 위하여 가열된 증기메탄을 제공하고, 이러한 기능을 가진 상단 추진기관시스템은 심우주탐사 등 다양한 임무에 확대 적용 가능할 것으로 기대된다.

DRUM impactor를 이용한 대기 입자상 물질 중 원소성분의 입경분포 특성 : 제주도 고산지역의 2002년 봄철 (3.29-5.30) 측정 연구 (Size Distributions of Trace Elements in Airborn Particulates Collected using Drum impactor at Gosan, Jeju Island : Measurements in Springtime 2002)

  • 한진석;문광주;류성윤;안준영;공부주;홍유덕;김영준
    • 한국대기환경학회지
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    • 제20권4호
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    • pp.555-569
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    • 2004
  • Size -segregated measurements of aerosol composition using 8-stage DRUM impactor are used to determine the transport of natural and anthropogenic aerosols at Gosan site from 29 March to 30 May in 2002. Separation of ambient aerosols by DRUM impactor offers many Advantages over other standard filtration techniques. Some of the most important advantages are the ability to segregate into details by particle tire, to better preserve chemical integrity since the air stream doesn't pars through the deposit, to collect samples as a function of time, and to have a wide variety of impaction surfaces available to match analytical needs. Although the transport of Yellow sand is a well-known phenomenon in springtime, the result of measurement shows that not only soil dust but also anthropogenic aerosols, including sulfur, enriched trace metals such as Pb, Ni, Zn. Cu, Cr, As, Se, Br, are transported to Gosan in springtime. This study combines the size- and time-resolved aerosol composition measurements with isentropic, backward air-mass trajectories in order to identify some potential source regions of anthropogenic aerosols. As a result, during the NYS period, the average concentration of PM$_{10}$ was 46$\mu\textrm{g}$/㎥, Si, Al. S, Fe, Cl, K, Ca were higher than 1,000 ng/㎥ and Ti was about 100 ng/㎥. The concentrations of Zn, Mn, Cu. Pb, Br, Rb, V, Cr, Ni. At, Se ranged between 1 and 70 ng/㎥. More than 50% typical soil elements, tuck as Al, Si, Fe, Cd. Ti, Cr, Cu, Br. were distributed in a coarse particle range(5.0-12${\mu}{\textrm}{m}$). In other hand, anthropogenic pollutants, luck as S, N, Vi, were mainly distributed in a fine particle range (0.09-0.56${\mu}{\textrm}{m}$). During the YS period, PM$_{10}$ increased about 8 times than NYS period, and main soil elements, such as Al, Si, S, K, V, Mn, Fe also doubled in coarse particle range (1.15-12${\mu}{\textrm}{m}$). But Zn, As, Pb, Cu and Se, which distributed in the time aerosols (0.09-0.56${\mu}{\textrm}{m}$), were on the same level with or decreased than NYS period. Finally. except the YS Period, coarse particles (2.5-12${\mu}{\textrm}{m}$) are inferred to be influenced by soil, coal combustion, waste incineration, ferrous and nonferrous sources through similar pathways with Yellow Sand. But fine particles have different sources, such as coal combustion, gasoline vehicle, biomass burning, oil or coal combustion, nonferrous and ferrous metal sources, which are transported from China, Korea peninsula and local sources.ces.

FGR 시스템 동력 플랜트 보일러의 성능 및 배기 배출물에 미치는 재순환 배기의 영향에 관한 연구 (A Study on Effect of Recirculated Exhaust Gas upon Performance and Exhaust Emissions in a Power Plant Boiler with FGR System)

  • 배명환;정광호;박성범
    • 대한기계학회논문집B
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    • 제40권4호
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    • pp.263-273
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    • 2016
  • 자연순환식 압입 송풍식 수관보일러에 FGR시스템을 설치하여 보일러 부하 및 공기량 댐퍼개도를 파라미터로 해서 FGR률에 따른 성능 및 배기 배출물에 미치는 재순환 배기의 영향을 조사하였다. 본 연구의 목적은 $NO_x$ 배출물을 저감시키기 위하여 동력플랜트 보일러에 FGR시스템을 적용하는 것이다. 연소를 활성화시키기 위해 0 ~ 20%의 연소용 공기를 화염 내에 공급한다. 공기상자 상부에 설치된 2단 연소시스템의 흡입댐퍼를 $0^{\circ}{\sim}90^{\circ}$ 사이에서 레버를 조작하여 열면, 버너로 공급되는 연소용 공기가 변화된다. 증발률당의 연료소비율은 FGR률의 증가에 따라 증가 혹은 감소의 명확한 경향을 나타내지 않았고, 동일 공기량 댐퍼개도에서는 FGR률이 증가할수록, 또한, 보일러 부하가 감소할수록 $NO_x$ 배출물이 감소되었다. 매연 배출물은 전기 집진기에서 86.7%의 포집효율로 매연이 제거되었기 때문에, 보일러 부하, 공기량 댐퍼 개도 및 FGR률의 운전조건에 관계없이 극소량의 매연이 배출되었다.

PMF 분석을 이용한 ACE-Asia 측정기간 중 제주 고산지역 입자상 물질의 입경별 발생원 추정 (Size-resolved Source Apportionment of Ambient Particles by Positive Matrix Factorization at Gosan, Jeju Island during ACE-Asia)

  • 문광주;한진석;공부주;정일록
    • 한국대기환경학회지
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    • 제22권5호
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    • pp.590-603
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    • 2006
  • Size-and time-resolved aerosol samples were collected using an eight-stage Davis rotating unit for monitoring (DRUM) sampler from 23 March to 29 April 2001 at Gosan, Jeju Island, Korea, which is one of the super sites of Asia-Pacific Regional Aerosol Characterization Experiment(ACE-Asia). These samples were analyzed using synchrotron X-ray fluorescence for 3-hr average concentrations of 19 elements including Al, Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, and Pb. The size-resolved data sets were then analyzed using the positive matrix factorization(PMF) technique to identify possible sources and estimate their contributions to particulate matter mass. PMF analysis uses the uncertainty of the measured data to provide an optimal weighting. Twelve sources were resolved in eight size ranges($0.09{\sim}12{\mu}m$) and included continental soil, local soil, sea salt, biomass/biofuel burning, coal combustion, oil combustion, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, and volcanic emission. The PMF result of size-resolved source contributions showed that natural sources represented by local soil, sea salt, continental soil, and volcanic emission contributed about 79% to the predicted primary particulate matter(PM) mass in the coarse size range ($1.15{\sim}12{\mu}m$) while anthropogenic sources such as coal combustion and biomass/biofuel burning contributed about 58% in the fine size range($0.56{\sim}2.5{\mu}m$). The diesel vehicle source contributed mostly in ultra-fine size range($0.09{\sim}0.56{\mu}m$) and was responsible for about 56% of the primary PM mass.

연탄이 연소할 때에 생성되는 일산화탄소에 대한 연구 (A Study of the Formation of Carbon Monoxide in the Combustion of Anthracite Holed Briquettes)

  • 한동진
    • 대한화학회지
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    • 제11권4호
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    • pp.150-158
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    • 1967
  • 연탄이 연소할 때 배기기체에 포함된 일산화탄소의 mole백분율(CO%)은 그 초기에 있어서 대략 다음 식으로 표시된다. (CO%)=$\frac{2{\alpha}}{1+{\alpha}}(CO_2%)$ exp $[-\vec{k}(No_2-Nc)^{1/2}{\tau}]$위식에서 ${\alpha}=\frac{-0.395K_p+\sqrt{0.156K^2_p+(0.83+0.21K_p)K_p}}{0.83+0.21K_p}$그리고 $logK_p =-\frac{8593}{T} + 2.45logT -1.08{\times}10^{-3}T + 1.12{\times}10^{-7}T^2+2.77\vec{k},\;No_2$$N_c$$CO+\frac{1}{2}O_2{\to}CO_2$의 반응속도상수, 그리고 1mole의 배기기체에 포함된 산소 및 탄소의 산화물의 mole수이다. 본 실험에서는 연소된 전 탄소의 값에 대해서 일산화탄소를 전환된 백분율 및 연소로 속에 들어가는 공기의 유량속은 다음과 같았다. 1.76%와 0.53l/sec (뚜껑이 있을 때) 및 12.35%와 2.4l/sec (뚜껑이 없을 때)

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