• 제목/요약/키워드: Combustion Conditions

검색결과 1,407건 처리시간 0.022초

천연가스 예혼합 분위기 내 디젤 연소의 최적화에 관한 연구 (A Study on Optimization of Diesel Combustion in condition of Premixed Natural gas)

  • 서현욱;전충환
    • 한국연소학회:학술대회논문집
    • /
    • 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
    • /
    • pp.141-142
    • /
    • 2014
  • This numerical study was carried out to optimize dual fuel combustion on natural gas-diesel in static chamber. Spray experiments conducted under conditions of premixed methan 0%, 5% and 10%. In the results, penetration decreases when premixed methane is increasing. Constants of numerical models were acquired from results of spray experiments to enhance accuracy of numerical study. And dual fuel engine simulation was implemented by using AVL-FIRE with acquired constants.

  • PDF

온라인 개방코드 OSCILOS를 이용한 모델 희박 예혼합 가스터빈 연소기의 연소불안정 해석 사례 (A Case Study on Combustion Instability of a Model Lean Premixed Gas Turbine Combustor with Open Source Code OSCILOS)

  • 차동진;송진관;이종근
    • 한국연소학회지
    • /
    • 제20권4호
    • /
    • pp.10-18
    • /
    • 2015
  • Combustion instability is a major issue in design and maintenance of gas turbine combustors for efficient operation with low emissions. With the thermoacoustic view point the instability is induced by the interaction of the unsteady heat release of the combustion process and the change in the acoustic pressure in the combustion chamber. In an effort to study the combustion dynamics of gas turbine combustors, Morgans et al (2014) have developed OSCILOS (open source combustion instability low order simulator) code and it is currently available online. In this study the code has been utilized to predict the combustion instability of a reported case for lean premixed gas turbine combustion, and then its prediction results have been compared with the corresponding experimental data. It turned out that both the predicted and the experimental combustion instability results agree well. Further the effects of some typical inlet acoustic boundary conditions on the prediction have been investigated briefly. It is believed that the validity and effectiveness of the open source code is reconfirmed through this benchmark test.

정적 연소 조건에서 Octane 단일 연료 액적의 매연 생성 거동에 관한 연구 (Experimental Study on the Soot Formation Behavior of Octane Single Fuel Droplet Under the Constant Volume Combustion Conditions)

  • 임영찬;서현규
    • 대한기계학회논문집B
    • /
    • 제41권6호
    • /
    • pp.389-395
    • /
    • 2017
  • 본 연구는 정적 연소 조건에서 Octane 단일 연료 액적의 매연 생성 거동에 관한 정보를 제공하기 위해 수행하였다. 이를 위해 동일한 분위기 압력($P_{amb}$) 1.0 atm과 산소 농도($O_2$) 21%, 질소 농도($N_2$) 79% 조건에서 초기 액적 직경($d_0$) 변화에 따른 Octane 액적의 매연 생성 특성 실험 결과를 제시하였다. Octane 액적 연소 가시화는 초고속 카메라를 사용하여 촬영하였고, 분위기 조건은 제어 시스템에 의해 동일한 조건을 유지하였다. Octane 액적 연소 결과, 매연 생성량은 동일한 분위기 조건에서 초기 액적 직경 변화의 영향이 크게 나타나지 않았다. 또한, 매연 체적 분율 최댓값($f_{vmax}$)은 $135^{\circ}{\sim}315^{\circ}$ 측정 방향에서 높은 결과를 보였다. 이는 액적 점화 이후 Igniter의 이동 과정에서 생성된 Soot-tail로 인해 매연 체적분율 결과가 증가된 것으로 나타났다.

정적연소기에서의 메탄-공기 혼합기의 연소특성(3) : 배기배출물 (Combustion Characteristics of Methane-Air Mixture in a Constant Volume Combustion Chamber(3) : Exhaust Emission)

  • 최승환;전충환;장영준
    • 한국자동차공학회논문집
    • /
    • 제12권2호
    • /
    • pp.1-8
    • /
    • 2004
  • A cylindrical constant volume combustion chamber was used to investigate the exhaust emission characteristics of homogeneous charge, stratified pattern and inhomogeneous charge under various conditions using gas chromatography. In the case of homogeneous charge condition, the $CO_2$ concentration is proportional to excess air ratio and overall charge pressure, the $CO_2$ concentration is proportional to excess air ratio and the UHC concentration is inversely proportional to ignition time and overall charge pressure. In the case of stratified pattern, the RI(rich injection) condition shows better exhaust emission characteristics, especially $CO_2$, than that of HI (homogeneous injection) or LI (lean injection) conditions. In inhomogeneous charge conditions, when initial charge pressure is increased, $CO_2$ and UHC concentration is reduced but $O_2$ concentration is increased. And when the excess air ratio of initial charge mixture is 3.0, UHC and $CO_2$concentration show lowest values.

소형선박 기관실의 자연발화 방지를 위한 환기조건에 관한 연구 (A Study on the Ventilation Conditions for the Prevention of Spontaneous Combustion of Small Ship Engine Room)

  • 박찬수
    • 한국화재소방학회논문지
    • /
    • 제22권4호
    • /
    • pp.11-19
    • /
    • 2008
  • 소형선박 기관실의 자연발화 방지를 위한 적합한 환기조건을 제시하기 위하여 급, 배기구 수와 위치를 변화시키면서 나타나는 유동장과 온도장을 CFD시뮬레이션을 수행하여 분석하였다. 급, 배기구 수와 위치에 따라 유동형태가 상이하게 나타났으며, 배기구를 천장에 배치시킬 경우는 세로대칭선에 대해 좌우 측천장의 중앙에 위치하는 것이 열 제거에 더 효과적임을 알 수 있었다. 급, 배기구 수를 증가시킬 때는 배기구수를 증가시키는 것이 더 적합한 환기조건이며, 소형선박 기관실의 자연발화방지에 가장 적합한 환기조건은 급기구는 가로대칭선에 대해 전후 측 천장의 중앙에, 배기구는 양측 벽 중앙에 배치시키는 경우로 예측되었다.

직분식 CNG 엔진에서 연료 분사시기의 변화가 연소 및 출력 특성에 미치는 영향 (The Effect of Fuel Injection Timing on Combustion and Power Characteristics in a DI CNG Engine)

  • 강정호;윤수한;이중순;박종상;하종률
    • 한국자동차공학회논문집
    • /
    • 제15권1호
    • /
    • pp.193-200
    • /
    • 2007
  • Natural gas is one of the most promising alternatives to gasoline and diesel fuels because of its lower harmful emissions, including $CO_2$, and high thermal efficiency. In particular, natural gas is seen as an alternative fuel for heavy-duty Diesel Engines because of the lower resulting emissions of PM, $CO_2$ and $NO_x$. Almost all CNG vehicles use the PFI-type Engine. However, PFI-type CNG Engines have a lower brake horse power, because of reduced volumetric efficiency and lower burning speed. This is a result of gaseous charge and the time losses increase as compared with the DI-type. This study was conducted to investigate the effect of injection conditions (early injection mode, late injection mode) on the combustion phenomena and performances in the or CNG Engine. A DI Diesel Engine with the same specifications used in a previous study was modified to a DI CNG Engine, and injection pressure was constantly kept at 60bar by a two-stage pressure-reducing type regulator. In this study, excess air ratios were varied from 1.0 to the lean limit, at the load conditions 50% throttle open rate and 1700rpm. The combustion characteristics of the or CNG Engine - such as in-cylinder pressure, indicated thermal efficiency, cycle-by-cycle variation, combustion duration and emissions - were investigated. Through this method, it was possible to verify that the combustion duration, the lean limit and the emissions were improved by control of injection timing and the stratified mixture conditions. And combustion duration is affected by not only excess air ratio, injection timing and position of piston but gas flow condition.

연소실 매개변수에 따른 천연가스 연소 특성 (Parametric Study on Combustion Characteristics of CNG Fuel)

  • 이성욱;송영모;백두성
    • 대한기계학회논문집B
    • /
    • 제32권7호
    • /
    • pp.513-517
    • /
    • 2008
  • A parametric study was made to understand the fundamentals of combustion of CNG fuel in a constant volume chamber in the respect of swirl effect, and the numbers of spark ignition. Optical devices were applied for the visualization of the physics of combustion, and combustion pressures and exhaust emission were measured at several equivalence ratios by controlling speeds of a swirling motor. When the speed of a swirling motor was raised the combustion conditions were improved. The corresponding maximum combustion pressure and heat release rate were increased and the speed of flame propagation was getting faster. This research may contribute to improve the performance of CNG engine and reduce emissions in future.

환형 가스터빈 연소기에서 종방향 및 횡방향 음향모드 커플링 (Acoustic Coupling between Longitudinal and Transverse Modes in an Annular Gas Turbine Combustor)

  • 김지환;김대식
    • 한국연소학회지
    • /
    • 제23권1호
    • /
    • pp.13-20
    • /
    • 2018
  • Transverse acoustic mode in annular combustion chambers affects air-fuel mixing characteristics in the nozzle and can result in heat release fluctuations in the combustor. In addition, the acoustic mode coupling between the nozzle and the combustion chamber is one of the key parameters determining combustion instability phenomenon in the annular combustor. In this study, acoustic coupling between the nozzle and annular combustor was numerically analyzed using 3D-based in house FEM code. As a result, it was found that the acoustic mode inside the combustion chamber at anti-node locations of the transverse mode was strongly influenced by the nozzle inlet boundary conditions.

소결층 내에서의 코크스와 무연탄의 연소 특성 비교 연구 (A Study on the Combustion Characteristics of Coke and Anthracite in an Iron Ore Sintering Bed)

  • 양원;양광혁;최상민;최응수;이덕원;김성만
    • 한국연소학회:학술대회논문집
    • /
    • 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
    • /
    • pp.141-148
    • /
    • 2004
  • Coal combustion in an iron ore sintering bed is a key parameter that determines quality of the sintered ores and productivity of the process. In this study, effects of the different types of coal coke and anthracite - on the combustion in the iron ore sintering bed are investigated by modeling and experiment. Fuel characteristics of coke and anthracite are observed through a few basic analysis and thermo-gravimetric analysis. It was found that coke has a higher reactivity than anthracite due to the difference of surface area and density. Those characteristics are reflected to the 1-D unsteady simulation of the iron ore sintering bed. Calculation results show that different reactivity of the fuel can affect the bed combustion, which implies the further investigation should be performed for obtaining optimal combustion conditions in the sintering bed.

  • PDF

정적연소기내 유동형태가 화염전파에 미치는 영향 연구 (An Experimental Study of the Effect of Flow on Flame Propagation in a Constant-Volume Combustion Chamber)

  • 정동수;오승묵;서승우;장영준
    • 한국자동차공학회논문집
    • /
    • 제3권2호
    • /
    • pp.136-145
    • /
    • 1995
  • The aim of this study is to gain a better understanding of the effect of a flow motion on the flame development by means of an optically-accessible constant-volume combustion chamber and the visualization technique of a combustion flame. At first, the characteristics of a flame propagation are investigated in the combustion field of the two kinds of flow conditions such as a quiescent and a flowing condition, and methane-air mixture is used as fuel. Then the same investigation is performed in two flow configurations : bulk flow motion type and turbulence generating type. In this study, the combustion phenomena are analyzed by measuring the combustion pressure, flame propagation speed, mean velocity, turbulent intensity, and mass fraction burned.

  • PDF