• 제목/요약/키워드: ignition characteristics

검색결과 1,155건 처리시간 0.026초

쌀과자의 자연발화 특성에 관한 연구 (A Study on the Characteristics of Spontaneous Ignition for Rice Cracker)

  • 김홍;강영구
    • 한국안전학회지
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    • 제10권4호
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    • pp.75-80
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    • 1995
  • Spontaneous ignition characteristics of rice cracker were observed by preforming experiments at constant ambient temperature. As the results of the experiments, the critical spontaneous ignition temperature were exponentially decreased with the increase of ambient temperature. Type of combustion of rice cracker are smouldering combustion at low ignition temperature and flame combustion at high temperature. The rice cracker containing pam oil showed lower spontaneous ignition temperature than pure rice cracker because of oxidation heat of pam oil.

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모델 섹터 연소기의 점화기 깊이에 따른 점화특성 연구 (Study on Ignition Characteristics Relating to Igniter Penetration Depth in a Model Sector Combustor)

  • 진유인;유경원;민성기;김홍집
    • 한국연소학회지
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    • 제22권2호
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    • pp.36-41
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    • 2017
  • Aero gas turbine engines must demonstrate their ability to be ignited on ground conditions or relighted in flight. The electric spark ignition is usually used in current aero gas turbine engines. Experiments on ignition characteristics relating to spark igniter penetration depth under atmospheric pressure and temperature conditions were conducted on the model combustor which is scaled in 1/18. Exciter was operated during 2 seconds, and successful ignition phenomena were confirmed by the pressure rising sharply in combustor. In addition, instantaneous ignition images were captured by a high-speed camera. It showed kernel propagation and successful ignition events in the sector model combustor. Ignition test results showed that ignition limit with increase in penetration depth of the igniter plug was wider. When the penetration depth of the igniter plug increased under the same fuel injection pressure condition, successful ignition events were obtained in higher differential pressure conditions between inlet and outlet of the combustor. The results demonstrate that the ratio of the combustible mixture, which is exposed to the high temperature environment around the igniter plug tip, increases. Thereby affect the combustor ignition performance.

혼합기의 유동 및 점화조건에 따른 초기화염의 전파특성 (The influence of Mixture Flow and the Ignition Conditions on the Initial Flame Propagation Characteristics)

  • 김진영;이중순;하종률
    • 한국자동차공학회논문집
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    • 제7권6호
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    • pp.57-64
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    • 1999
  • Initial flame development and propagation were visualized under the new ignition system developed to estimate the effects of ignition characteristics on the engine performance in a port injection SI engine. Effects of intake air flow characteristics were also investigated by three different kinds of the swirl control valve. Experiments were performed in an optical single cylinder engine modified form a commercial engine. Flame images were captured through the quartz window mounted in the piston by the high speed video camera and analyzed to compare initial flame development. Results show that IMEP tends to rise slightly as the ignition duration gets longer. The direction of flame propagation is decisively governed by the in-cylinder flow motion. Every flame grows toward the exhaust valve forming a kind of turbulent flame. Initial flame propaagation characteristics are very similar to ones analyzed form pressure data.

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The Effect of Particle Size on Ignition Characteristics of Pulverized High-Volatile Bituminous Coal

  • Kim, Hyung-Taek
    • 에너지공학
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    • 제2권3호
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    • pp.285-292
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    • 1993
  • A cylindrical-shape, horizontal furnace was used to investigate the effect of particle size on the pulverized coal combustion behavior. Three differently-sized fractions (5, 30, and 44 microns in average diameter) of high-volatile bituminous coal, were burned in the test furnace. Ignition characteristics of pulverized coal flame were determined through the amount of methane in the carrier gas for the self-sustaining flame. Easiest ignition occurred with the immediately-sized coal particles. Ignition of coal jet flame appeared to occur through a gas-phase homogeneous process for particles larger than 30 microns. Below this limiting size, heterogeneous process probably dominated ignition of coal flame. Oxygen concentration of combustion air was varied up to 50%, to determine the oxygen-enrichment effect on the coal ignition behavior. Oxygen enrichment of primary air assisted ignition behavior of pulverized coal flame. However, enrichment of secondary air didn't produce any effect on the ignition behavior.

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스파크점화직분식 CNG의 점화성 및 연소화염 특성에 대한 연구 (An Experimental Study on the Ignition Probability and Combustion Flame Characteristics of Spark-Ignited Direct-Injection CNG)

  • 황성일;정성식;염정국;전병열;이진현
    • 한국분무공학회지
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    • 제21권1호
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    • pp.37-46
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    • 2016
  • For the SI engines, at only full load, the pumping loss has a negligible effect, while at part load conditions, the pumping loss increases. To avoid the pumping loss, the spark-ignited engines are designed to inject gasoline directly into the combustion chamber. In the spark-ignited direct-injection engines, ignition probability is important for successful combustion and the flame propagation characteristics are also different from that of pre-mixed combustion. In this paper, a visualization experiment system is designed to study the ignition probability and combustion flame characteristics of spark-ignited direct-injection CNG fuel. The visualization system is composed of a combustion chamber, fuel supply system, air supply system, electronic control system and data acquisition system. It is found that ambient pressure, ambient temperature and ambient air flow velocity are important parameters which affect the ignition probability of CNG-air mixture and flame propagation characteristics and the injected CNG fuel can be ignited directly by a spark-plug under proper ambient conditions. For all cases of successful ignition, the flame propagation images were digitally recorded with an intensified CCD camera and the flame propagation characteristics were analyzed.

4기통 디젤기관에 적용한 천연가스 예혼합 압축착화 기관의 연소특성 (Combustion Characteristics of Pre-mixed Charge Compression Ignition Engines with Natural Gas Applied to 4-Cylinders Diesel Engine)

  • 정석호
    • 동력기계공학회지
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    • 제13권2호
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    • pp.5-10
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    • 2009
  • In recently, studies concerned to the diesel engine uses a natural gas as a fuel oil whose infra has been built already was approached to PCCI or HCCI with keeping a high thermal efficiency and reducing NOx and PM have been researching actively in normally single cylinder. An ignition source is required to bum the natural gas by a spark plug in gasoline engines, due to a higher auto-ignition temperature of natural gas. Then gas oil and DME were introduced as the ignition source. In this study as basic data for practical use of natural gas PCCI and HCCI engines, combustion characteristics and emission characteristics on 4-cylinders natural gas PCCI and HCCI engines with gas oil and DME as ignition sources were analyzed and the engine load range that is main object for practical use of PCCI and HCCI engines was made clearly by empirical experiment.

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플라즈마를 이용한 분말형 금속 연료 알루미늄의 점화 특성 (Ignition Characteristics of Aluminum Metal Powder Fuel with Thermal Plasma)

  • 이상협;임지환;윤웅섭
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2011년도 제37회 추계학술대회논문집
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    • pp.737-744
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    • 2011
  • 탄화수소 계열의 점화원과 달리 선행 연구된 스팀 플라즈마 점화기를 이용한 알루미늄 분말의 지속 연소 성공을 바탕으로, 고온의 플라즈마를 이용한 알루미늄 분말의 점화 특성을 알아보기 위해 산화제가 없는 환경을 조성하여 점화 특성 확인 실험을 수행하였다. 아르곤 플라즈마를 이용하여 이전의 연소 실험과 동일한 4500 K의 온도 조건 및 이송 가스를 이용한 입자 공급 조건을 조성하여 실험을 수행하였으며, 플라즈마의 온도는 방출분광법을 사용하여 측정하였고 점화 특성은 SEM 촬영과 EDS 분석을 통해 비교 분석하였다. 고온의 플라즈마 제트 내부를 통과한 알루미늄 분말은 탄화수소 계열의 점화원과 다르게 급격한 기화로 인한 점화 촉진 효과를 확인 할 수 있었다.

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Theoretical Analysis on the Hot Surface Ignition of a Rectangular-Shape Solid Fuel

  • Kim, Se-Won
    • 에너지공학
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    • 제4권2호
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    • pp.297-302
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    • 1995
  • Ignition of a reactive solid in a shape of square corner by a hot surface is studied theoretically. Ignition time and the location of ignition point are determined as a function of dimensionless parameters, with the use of the homogeneous model of ignition. The effect of geometry on the ignition of solid fuel results in the local characteristics: the reaction is initiated in a hot point in depth of the substance. It is shown that ignition time is proportional to the dimensionless initial temperature, whereas for the ignition of the semiinfinite body this dependence was quadratic.

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예연소실 점화플러그의 화염가시화와 화염전파특성 (Flame Visualization and Flame Characteristics of Spark Plug with Pre-ignition Chamber)

  • 지명석;정인태
    • 한국가시화정보학회지
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    • 제14권3호
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    • pp.51-58
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    • 2016
  • New concept spark plug was developed to study its influence on the combustion characteristics of SI engine. It has pre-ignition chamber at the lower end of spark plug and flame hole, in which fresh mixture gas can be put in through the flame hole without any fuel supply system. This spark plug was tested in a single cylinder engine dynamometer for different air fuel ratio to measure the fuel consumption rate, emission gases, and MBT timing. And constant volume combustion chamber was made to understand flame characteristics of spark plug. New spark plug induced fast burn compared to the conventional spark plug and its effects were increased in lean air fuel ratio. Pre-ignition chamber spark plug with 5 holes which had adjusted size was more stable and effective in combustion performance than pre-ignition chamber spark plug with 1 hole. And its effects showed larger differences in lean air fuel ratio than stoichiometric condition. Flame kernel and flame growth process of conventional spark plug and pre-ignition chamber spark plug studied by flame visualization of schlieren method.

연료조성에 따른 HCCI 엔진의 냉염 및 열염의 2단연소 특성에 관한 실험적 연구 (An Experimental Study on the Two Stage-Ignition of Cool Flame and Hot Flame in HCCI Engine According to Fuel Composition)

  • 김형민;류재덕;이기형;이창식
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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    • pp.13-19
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    • 2003
  • As the environmental pollution becomes serious global problem, the regulation of emission exhausted from automobiles is strengthen. Therefore, it is very important to know how to reduce the NOx and PM simultaneously in diesel engines, which has lot of merits such as high thermal efficiency, low fuel consumption and durability. By this reason, the new concept called as Homogeneous Charge Compression Ignition(HCCI) engines are spotlighted because this concept reduced NOx and P.M. simultaneously. However, it is well known that HCCI engines increased HC and CO. Thus, the investigation of combustion characteristics which consists cool and hot flames for HCCI engines were needed to obtain the optimal combustion condition. In this study, combustion characteristics for direct inject type HCCI engine such as quantity of cool flame and hot flame, ignition timing and ignition delay were investigated to clarify the effects of these parameters on performance. The results revealed that diesel combustion showed the two-stage ignition of cool flame and hot flame, the rate of cool flame increase and hot flame decrease with increasing intake air temperature. On the other hand, the gasoline combustion is the single-stage ignition and ignition timing is near the TDC. In addition mixed fuel combustion showed different phenomenon, which depends on the ratio of gasoline component. Ignition timing of mixed fuel is retarded near the TDC and the ignition delay is increased according to ratio of gasoline.

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