• 제목/요약/키워드: 디젤화염

검색결과 48건 처리시간 0.026초

대체 연료인 DME 혼합에 의한 대향류 에틸렌 확산화염내 매연 생성에 대한 실험적 연구 (Experimental Study on Soot Formation in Opposed-Flow Ethylene Diffusion Flames by Mixing DME as an Alternative Fuel)

  • 윤두호;윤석훈;최재혁
    • 해양환경안전학회지
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    • 제16권3호
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    • pp.301-306
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    • 2010
  • DME는 환경 친화적인 특성으로 인해 현재 전 세계적으로 주목을 받고 있다. 지금까지 DME는 매연을 적게 생산하는 청정 에너지라는 특성으로 인해 디젤 자동차의 주요 대체 에너지로서 연구되어 왔다. 이에 본 연구에서는 에틸렌 대향류 확산화염에 DME를 5%, 14% 및 30% 혼합했을 때, DME의 혼합 비율에 따른 매연의 수밀도 및 크기에 대한 영향을 조사하였다. 레이저 투과법 및 산란법을 이용해 수밀도 및 크기를 측정하였다. 그 결과 DME를 30% 혼합한 경우에는 매연이 감소한 반면, 5%와 14%의 혼합 비율에서는 매연이 증가하는 경향을 나타내었다. 이 결과는 DME가 매연 생성이 적은 청정 연료로 알려진 것과는 달리 에틸렌 확산화염 내에서는 DME의 혼합에 따라 매연 생성이 증가될 수 있다는 것을 의미한다.

파일럿분사에 의한 바이오디젤유의 연소과정에 관한 연구 (A Study on Combustion Process of Biodiesel Fuel with Pilot Injection in a Common-rail Diesel Engine)

  • 방중철;김성훈
    • 한국자동차공학회논문집
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    • 제19권3호
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    • pp.146-153
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    • 2011
  • American NREL (National Renewable Energy Laboratory) reported that BDF20 could reduce PM, CO, SOx, and cancerogenic matters by 13.6%, 9.3%, 17.6%, and 13% respectively, compared to diesel fuel. BDF20 has been being tested on garbage trucks and official vehicles at Seoul City, which is positive on air environment, but negative on combustion by higher viscosity in winter season. This study investigated the combustion characteristics by applying pilot injection for improving the deterioration of combustibility caused by the higher viscosity of the BDF20 with the combustion flames taken by a high-speed camera and the cylinder pressure diagram. A 4-cycle single-cylinder diesel engine was remodeled to a visible 2-cycle engine taking the flame photographs, which has a common-rail injection system. The test was done laboratory temperature at $5{\sim}6^{\circ}C$. The results obtained are summarized as follows, (1) In the case of without pilot injection, the flame propagation speed was slowed and the maximum combustion pressure became lower. The phenomena became further aggravated as the fuel viscosity gets higher. (2) In the case of with pilot injection, early stage of combustion such as rapid ignition timing and flame propagation was activated since intermediate products formed by pilot injection act as a catalyst for combustion of main fuel.

Swirl Groove Piston에 의한 바이오 디젤연료의 연소과정에 관한 연구 (A Study on Combustion Process of Biodiesel Fuel using Swirl Groove Piston)

  • 방중철;김성훈
    • 한국자동차공학회논문집
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    • 제17권1호
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    • pp.105-113
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    • 2009
  • The performance of a direct-injection type diesel engine often depends on the strength of swirl or squish, shape of combustion chamber, the number of nozzle holes, etc. This is of course because the combustion in the cylinder was affected by the mixture formation process. In this paper, combustion process of biodiesel fuel was studied by employing the piston which has several grooves with inclined plane on the piston crown to generate swirl during the compression stroke in the cylinder in order to improve the atomization of high viscosity fuel such as biodiesel fuel and toroidal type piston generally used in high speed diesel engine. To take a photograph of flame, single cylinder, four stroke diesel engine was remodeled into two stroke visible engine and high speed video camera was used. The results obtained are summarized as follows; (1) In the case of toroidal piston, when biodiesel fuel was supplied to plunger type injection system which has very low injection pressure as compared with common-rail injection system, the flame propagation speed was slowed and the maximum combustion pressure became lower. These phenomena became further aggravated as the fuel viscosity gets higher. (2) In the case of swirl groove piston, early stage of combustion such as rapid ignition timing and flame propagation was activated by intensifying the air flow in the cylinder. (3) Combustion process of biodiesel fuel was improved by the reason mentioned in paragraph (2) above. Consequently, the swirl grooves would also function to improve the combustion of high viscosity fuel.

고속 직분식 디젤 엔진에서의 점화지연시기 예측 (Prediction of Ignition Delay for HSDI Diesel Engine)

  • 임재만;김용래;온형석;민경덕
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 추계학술대회
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    • pp.1704-1709
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    • 2004
  • New reduced chemical kinetic mechanism for prediction of autoignition process of HSDI diesel engine was investigated. For precise prediction of the ignition characteristics of diesel fuel, mechanism coefficients were fitted by the experimental results of ignition delay of diesel spray in a constant volume vessel. Ignition delay of diesel engine on various operation condition was calculated based on the new reduced chemical mechanism. The calculation results agreed well with experimental data.

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디젤엔진에서 Cavity 내 .외측의 화염온도와 KL치에 관한 연구 (A Study on the Flame Temperature and KL Value in Inner and Outer Cavity in a D.1. Diesel Engine)

  • 이태원;윤수한;정성식;하종률
    • 한국자동차공학회논문집
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    • 제10권3호
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    • pp.18-27
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    • 2002
  • Flame behavior in inner and outer the cavity and flame temperature have an important influence on the formation and oxidation of NOx and soot. Therefore, in this study, the combustion chamber of toroidal and reentrant that have different flow characteristics of inside and outside the cavity and load, and so forth are determined as parameters of experimental conditions. An attempt has been made to obtain the effect of flame temperature and KL value in idler and outer cavity on the formation and oxidation of soot using the two-color method.

디젤 엔진 운전 조건에서 분무 연소 과정과 난류 화염 구조 특성에 대한 해석 (Characteristization of Spray Combustion and Turbulent Flame Structures in a Typical Diesel Engine Condition)

  • 이영재;허강열
    • 한국연소학회지
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    • 제14권3호
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    • pp.29-36
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    • 2009
  • Simulation is performed to analyze the characteristics of turbulent spray combustion in a diesel engine condition. An extended Conditional Moment Closure (CMC) model is employed to resolve coupling between chemistry and turbulence. Relevant time and length scales and dimensionless numbers are estimated at the tip and the mid spray region during spray development and combustion. The liquid volume fractions are small enough to support validity of droplets assumed as point sources in two-phase flow. The mean scalar dissipation rates (SDR) are lower than the extinction limit to show flame stability throughout the combustion period. The Kolmogorov scales remain relatively constant, while the integral scales increase with decay of turbulence. The chemical time scale decreases abruptly to a small value as ignition occurs with subsequent heat release. The Da and Ka show opposite trends due to variation in the chemical time scale. More work is in progress to identify the spray combustion regimes.

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부분 예혼합 압축착화 조건에서 디젤분무의 화염특성 (Flame Characteristics of Diesel Spray in the Condition of Partial Premixed Compression Ignition)

  • 방중철;박철환
    • 한국연소학회지
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    • 제17권2호
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    • pp.24-31
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    • 2012
  • Diesel engines exhaust much more NOx(Nitrogen Oxides) and PM(Particulate Matter) than gasoline engines, and it is not easy to reduce both NOx and PM simultaneously because of the trade-off relation between two components. This study investigated flame characteristics of the partial premixed compression ignition known as new combustion method which can reduce NOx and PM simultaneously. The investigation was performed through the analysis of the flame images taken by a high speed camera from the visible engine which is the modified single cylinder diesel engine. The results obtained through this investigation are summarized as follows; (1) The area of the luminous yellow flame was reduced due to the decrease of flame temperature and even distribution of temperature. (2) The darkish yellow flame zone caused by the shortage of the remaining oxygen after the middle stage of combustion was considerably reduced. (3) Since the ignition delay was shortened, the violent combustion did not occur and the combustion duration became shortened.

DME연료 디젤 엔진에서의 연소특성 해석 (Numerical Studies on Combustion Characteristics of Diesel Engines using DME Fuel)

  • 유용욱;이정원;김용모
    • 한국자동차공학회논문집
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    • 제16권2호
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    • pp.143-149
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    • 2008
  • The present study is mainly motivated to investigate the vaporization, auto-ignition and spray combustion processes in DI diesel engine using DME and n-heptane. In order to realistically simulate the dimethyl ether (DME) spray dynamics and vaporization characteristics in high-pressure and high-temperature environment, the high-pressure vaporization model has been utilized. The interaction between chemistry and turbulence is treated by employing the Representative Interaction Flamelet (RIF) model. The detailed chemistry of 336 elementary steps and 78 chemical species is used for the DME/air reaction. Based on numerical results, the detailed discussion has been made for the distinctly different combustion characteristics of DME diesel engine in term of vaporization, ignition delay, pollutant formation, and heat release rate.

디젤엔진에서의 PCCI 연소 특성과 화염 가시화에 관한 연구 (A Study on the PCCI Combustion Characteristics and Flame Visualization in a Diesel Engine)

  • 박진규;이재민;김형익;김영진;이기형
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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    • pp.191-193
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    • 2012
  • The use of diesel engines has recently increased due to the need for internal combustion engines with a high thermal efficiency and low harmful exhaust gas. The PCCI(premixed charged compression ignition) technology has been studied specifically to simultaneously reduce NOx and PM. While the PCCI means has the merit of reducing NOx and PM, control of the combustion phase is difficult. In this study, Flame visualization was then performed with an endoscope system in order to compare combustion flame characteristics in an commercial diesel engine.

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DME 및 n-Heptane 연료의 디젤엔진 조건에서 분무연소특성 해석 (Numerical Study on the Characteristics of Spray Combustion Processes in the DME and n-heptane Fueled Diesel-like Engine Conditions)

  • 유용욱;석준호;이상길;김용모
    • 한국분무공학회지
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    • 제13권2호
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    • pp.91-98
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    • 2008
  • In the present study, in order to understand the overall spray combustion characteristics of DME fuel as well as to identify the distinctive differences of DME combustion processes against the conventional hydrocarbon liquid fuels, the sequence of the comparative analysis have been systematically made for DME and n-heptane liquid fuels. To realistically represent the physical processes involved in the spray combustion, this studyemploys the hybrid breakup model, the stochastic droplet tracking model, collision model, high-pressure evaporation model, and transient flamelet model with detailed chemistry. Based on numerical results, the detailed discussions are made in terms of the autoignition, spray combustion processes, flame structure, and turbulence-chemistry interaction in the n-heptane and DME fueled spray combustion processes.

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