• 제목/요약/키워드: ignition characteristics

검색결과 1,155건 처리시간 0.027초

액체로켓엔진 재생냉각 연소기의 점화 특성 연구 (A Study on the Ignition Characteristics of Liquid Rocket Engine Thrust Chamber with Regenerative Cooling)

  • 이광진;한영민;김종규;최환석
    • 한국추진공학회지
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    • 제16권6호
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    • pp.73-78
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    • 2012
  • 국내 기술로 개발된 액체로켓엔진 연소기의 점화 특성을 연소시험을 통해 분석하였다. 연소시험에 사용된 연소기들은 점화제용 분사기, 막냉각 방식 그리고 산화제 입구 위치가 다른 특징을 지니며 각기 다른 시동 시퀀스를 적용하였다. 분석결과 산화제 매니폴드의 온도 프로파일에 따라 저주파 섭동이 점화구간 내에서 나타남을 보였다. 이 저주파 섭동은 연소기의 기능장애를 유발하지는 않았지만, 엔진 시스템 및 발사체와의 인터페이스측면에서 지속적인 관심 요소로서 관찰이 요구된다.

Burning Characteristics of Wood-based Materials using Cone Calorimeter and Inclined Panel Tests

  • Park, Joo-Saeng;Lee, Jun-Jae
    • Journal of the Korean Wood Science and Technology
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    • 제30권3호
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    • pp.18-25
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    • 2002
  • Research to discuss the fire performance of materials requires tools for measuring their burning characteristics and validated fire growth models to predict fire behavior of the materials under specific tire scenarios using the measured properties as input for the models. In this study, burning characteristics such as time to ignition, weight loss rate, flame spread, heat release rate, total heat evolved, and effective heat of combustion for four types of wood-based materials were evaluated using the cone calorimeter and inclined panel tests. Time to ignition was affected by not only surface condition and specific gravity of the tested materials but also the type and magnitude of heat source. Results of weight loss rate, measured by inclined panel tests, indicated that heat transfer from the contacted flame used as the heat source into the inner part of the specimen was inversely proportional to specific gravity of material. Flame spread was closely related with ignition time at the near part of burning zone. Under constant and severe external heat flux, there was little difference in weight loss rate and total heat evolved between four types of wood-based panels. More applied heat flux caused by longer ignition time induced a higher first peak value of heat release rate. Burning characteristics data measured in this study can be used effectively as input for fire growth models to predict the fire behavior of materials under specific fire scenarios.

LPG-DME 압축착화 엔진의 성층화 영향 (Fuel Stratification Effects of LPG-DME Compression Ignition Engine)

  • 염기태;배충식
    • 한국자동차공학회논문집
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    • 제16권1호
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    • pp.78-85
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    • 2008
  • The exhaust emission characteristics of a liquefied petroleum gas-di-methyl ether (LPG-DME) compression ignition engine was investigated under homogeneous charge, stratified charge and diffusion combustion conditions. LPG was used as the main fuel and injected into the combustion chamber directly. DME was used as an ignition promoter and injected into the intake port. Different LPG injection timings were tested to verify the combustion characteristics of the LPG-DME compression ignition engine. The combustion was divided into three region which are homogeneous charge, stratified charge, and diffusion combustion region according to the injection timing of LPG. The HC emission was reduced with LPG stratification. However, the carbon monoxide and particulate matter emissions were increased. The ignition timing was advanced with LPG stratification. This advance combustion was because of charge temperature and cetane number stratification with LPG.

압축점화 가솔린기관의 성능 및 배기특성 (Performance and Emission Characteristics of Compression Ignition Gasoline Engine)

  • 김홍성;김문헌
    • 대한기계학회논문집B
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    • 제27권7호
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    • pp.1007-1014
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    • 2003
  • This work deals with a controlled auto-ignition (CAI) single cylinder gasoline engine, focusing on the extension of operating conditions. The fuel is injected indirectly into electrically heated inlet air flow. In order to keep a homogeneous air-fuel mixing, the fuel injector is water-cooled by a specially designed coolant passage. Investigated are the engine performance and emission characteristics under the wide range of operating conditions such as 32 to 63 in the air-fuel ratio, 1000 to 1800 rpm in the engine speed, and 150 to 18$0^{\circ}C$ in the inlet air temperature. The compression ignition gasoline engine can be achieved that the ultra lean-burn with self-ignition of gasoline fuel by heating inlet air. For example. the allowable lean limit of air-fuel ratio is extended until 63 at engine speed of 1000 rpm and inlet air temperature of 17$0^{\circ}C$. It can be achieved that the emission concentrations of carbon monoxide, hydrocarbons and nitrogen oxide had been significantly reduced by CAI combustion compared with conventional spark ignition engine.

직접분사식 디젤기관의 착화지연기간에 대한 고찰 (Some Considerations of the Ignition Delay Period in D.I Diesel Engine)

  • 방중철
    • 한국자동차공학회논문집
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    • 제18권2호
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    • pp.97-103
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    • 2010
  • The four combustion stages in a diesel engine have close correlation among them. Especially, the ignition delay period has significant effect on the following combustion stage. And the period is also one of inevitable combustion processes in the diesel engine. For example, the diesel knocking is a well-known phenomenon due to the long ignition delay period. The interval of the ignition delay period is affected by the mixture formation process in the cylinder. However, in the case of the D.I. diesel engine, the available duration to make the mixture formation of air-fuel is very short. In addition, the means of the mixture formation mainly depends on the injection characteristics and properties of the fuel. It is difficult to make complete mixture. Therefore, an early stage of combustion is violent, which leads to the weakness of noise and vibration. In this study, using the visible engine, we measured the ignition delay period by photo sensor which detect occurrence of flame and presented the factors of the injection characteristics such as kinds of injection system, the injection pressure and the injection timing. The relation between the ignition delay period and cylinder pressure diagram which was concurrently obtained was also estimated.

분사시기의 변화에 따른 제어자발화 가솔린기관의 성능 및 배기특성 (Performance and Emission Characteristics of a Controlled Auto-Ignition Gasoline Engine according to Variation of the Injection Timing)

  • 김홍성
    • 동력기계공학회지
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    • 제9권1호
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    • pp.14-22
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    • 2005
  • This work deals with a controlled auto-ignition (CAI) single cylinder gasoline engine, focusing on the extension of operating conditions. The fuel is injected indirectly into electrically heated inlet air flow. In order to keep a homogeneous air-fuel mixing, the fuel injector is water-cooled by a specially designed coolant passage. Investigated are the engine performance and emission characteristics under the wide range of operating conditions such as 40 in the air-fuel ratio, 1000 to 1800 rpm in the engine speed, $150\;to\;180^{\circ}C$ in the inlet-air temperature, and $80^{\circ}$ BTDC to $20^{\circ}$ ATDC in the injection timing. A controlled auto-ignition gasoline engine can be achieved that the ultra lean-burn with self-ignition of gasoline fuel by heating inlet air. It can be achieved that the emission concentrations of carbon monoxide, hydrocarbons and nitrogen oxide had been significantly reduced by CAI combustion compared with conventional spark ignition engine.

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EDB에 의해 부양된 알루미늄과 마그네슘 단일 입자의 점화 및 연소 특성 비교 연구 (Comparison Study on Burning and Ignition Characteristics for Single Aluminum and Magnesium Particles)

  • 임지환;윤웅섭
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2010년도 제35회 추계학술대회논문집
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    • pp.311-316
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    • 2010
  • The ignition and the burning characteristics of aluminum and magnesium particles ($30-110{\mu}m$ in diameter) isolated due to electrodynamic levitation were experimentally investigated. The burning time, the ignition delay time, the flame temperature, and the flame diameter were measured. The thermal radiation intensity was measured using the photomultiplier tube and the combustion history was monitored by high-speed cinematography. Two-wavelength pyrometry measured the temperature of the burning particles. The burning times of aluminum particles were measured approximately 5 to 8 times longer than those of magnesium particles. Exponents of $D^n$-law, for the burning rate of magnesium and aluminum particles of diameters less than $110{\mu}m$, are found to be 0.6 and 1.5, respectively. The instant of aluminum ignition is clearly distinguished with the ignition delay time little less than 10 ms, however the burning history of magnesium particle exhibits no distinct instant of the ignition. The ignition delay time of magnesium particle (less than $110{\mu}m$) were approximately shown in the range from 50 to 200 ns. The flame temperatures of single metal particles are lower than the boiling point of the oxide. The nondimensional flame diameters for magnesium are decreased with increasing of the diameter. The nondimensional flame diameters for aluminum are not changed significantly.

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흡입공기온도의 변화에 따른 제어자발화 가솔린기관의 성능 및 배기 특성 (Performance and Emission Characteristics of a Controlled Auto-Ignition Gasoline Engine according to Variation of the Inlet-Air Temperature)

  • 김홍성
    • 동력기계공학회지
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    • 제10권1호
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    • pp.19-24
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    • 2006
  • This work treats a controlled auto-ignition (CAI) single cylinder gasoline engine, focusing on the extension of operating conditions. The fuel was injected indirectly into electrically heated inlet air flow. In order to keep a homogeneous air-fuel mixing, the fuel injector was water-cooled by a specially designed coolant passage. The engine performance and emission characteristics were investigated under the wide range of operating conditions such as 40 in the air-fuel ratio, 1000 to 1800 rpm in the engine speed, 150 to $180^{\circ}C$ in the inlet-air temperature, and $60^{\circ}$ BTDC in the injection timing. The ultra lean-burn with self-ignition of gasoline fuel by heating inlet air was achieved in a controlled auto-ignition gasoline engine. It could be also achieved that the emission concentrations of carbon monoxide, hydrocarbons and nitrogen oxide significantly reduced by CAI combustion compared with conventional spark ignition engines.

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점화에너지 및 방전시간이 스파크 점화 기관의 성능에 미치는 영향 (A Study on the Effects of Ignition Energy and Discharge Duration on the Performances of Spark Ignited Engines)

  • 송정훈;서영호;선우명호
    • 한국자동차공학회논문집
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    • 제9권6호
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    • pp.40-46
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    • 2001
  • An experimental investigation is proceeded to study on the relationship between spark ignition characteristics and the performances of an S. I. engine. The ignition parameters examined in this study are the ignition energy and discharging duration. The combustion pressure and exhaust gas are measured during the experiment. From the measured data of cylinder pressure, the heat release rate, the mass fraction burned, and the COV of IMEP are calculated. The dwell time and the injection time are varied. A single cylinder engine and a 30kW dynamometer are employed. Four different kinds of ignition systems are assembled, and one commercial ignition system is adopted. The experimental results show that the ignition energy is increased as the dwell time extended until the ignition energy is saturated. The higher ignition energy is effective in achieving the laster burning velocity and less producing HC emission. However, when the amount of ignition energy is similar, while the discharge duration becomes longer, the burning velocity is reduced but the engine operation becomes stable in terms of the COV of IMEP.

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Analysis of Compression-induced Auto-ignition Combustion Characteristics of HCCI and ATAC Using the Same Engine

  • Iijima, Akira;Shoji, Hideo
    • Journal of Mechanical Science and Technology
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    • 제20권9호
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    • pp.1449-1458
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    • 2006
  • Controlled Auto-ignition (CAI) combustion processes can be broadly divided between a CAI process that is applied to four-cycle engines and a CAI process that is applied to two-cycle engines. The former process is generally referred to as Homogeneous Charge Compression Ignition (HCCI) combustion and the later process as Active Thermo-Atmosphere Combustion (ATAC) The region of stable engine operation differs greatly between these two processes, and it is thought that the elucidation of their differences and similarities could provide useful information for expanding the operation region of HCCI combustion. In this research, the same two-cycle engine was operated under both the ATAC and HCCI combustion processes to compare their respective combustion characteristics. The results indicated that the ignition timing was less likely to change in the ATAC process in relation to changes in the fuel octane number than it was in the HCCI combustion process.