• 오토저널
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• 제10권5호
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• pp.42-53
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• 1988

The effects of ignition position on combustion in a chamber with swirl flow were investigated by use of hot wire anemometer, high speed schlieren photography, and chamber pressure measurement. In experiments, the closed-constant volume combustion chamber was used, and the swirl was formed unsteadily by suction of external fluid after reducing pressure in the chamber. Results show that the effect of ignition position on combustion depends on the flow state and the flame propagation distance corresponding to each ignition position. Also, the effect of combustion promoting increases as an ignition position moves from the center of chamber to the outside, but maximum burning pressure was obtained at the position that is the shortest flame propagation distance.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.814-819
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• 2017

본 논문에서는 점화 위치 및 시간에 따른 점화 지연 및 연소 불안정에 미치는 영향을 관찰하는 것이 목표이다. 산화제는 기체 산소를 사용하였고 연료는 액체 케로신을 사용하였다. 점화 지연 및 연소 불안정 정도를 관찰하기 위해 압력 트랜스듀서를 이용하여 정압을 측정하였다. 점화 위치는 분사기 스페이서를 이용하여 변경하였다. 모든 경우의 점화기 작동 시기를 제외한 점화 시퀀스는 동일하게 설정하였고 점화 시간은 25 ms 간격으로 설정하였다. 점화 시간이 늦어질수록 초기 압력 피크값과 점화 지연 시간이 증가하는 경향을 보였다. 점화 위치가 분사기로부터 멀어질수록 초기 압력 피크 이후 불안정한 화염 발달 구간이 존재하였다.

• Korean Journal of Acupuncture
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• 제25권1호
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• pp.247-257
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• 2008

Objectives : The warm needling technique is the method in combining the effects of acupuncture needle with the effects of moxibustion. We need to standardize the characteristics of the warm needling technique in order to get more systematic and objective result in operation mechanism and effects and then get more clinical abilities in these fields. Methods : In this study, using of labview system on the warm needling technique we studied about measurement and comparison with partial temperature changes according to the position of ignition. Results & conclusion : When we measured the warm needling's partial temperature according to the position of ignition, the bottom ignition method got the higher result on the peak temperature measured at 2cm below the head than the apex ignition method.

• 한국추진공학회지
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• 제22권4호
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• pp.85-90
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• 2018

본 논문에서는 점화 위치 및 시간에 따른 점화 지연 및 연소 불안정에 미치는 영향을 관찰하는 것이 목표이다. 산화제는 기체 산소를 사용하였고 연료는 액체 케로신을 사용하였다. 점화 지연 및 연소 불안정 정도를 관찰하기 위해 압력 트랜스듀서를 이용하여 정압을 측정하였다. 모든 경우의 점화기 작동시기를 제외한 점화 시퀀스는 동일하게 설정하였고 점화 시간은 25 ms 간격으로 설정하였다. 점화 시간이 늦어질수록 초기 압력 피크값과 점화 지연 시간이 증가하는 경향을 보였다. 점화 위치가 분사기로부터 멀어질수록 초기 압력 피크 이후 불안정한 화염 발달 구간이 존재하였다.

• 한국연소학회지
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• 제4권2호
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• pp.1-10
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• 1999

Pulverized coal is widely used as the source of electrical power generation and industrial processes. Numerical analysis on the transient ignition process of the cloud of pulverized coal particles in various cases is carried out. Particle radius, initial particle temperature, number density are chosen as major parameters that influence the characteristics of ignition and combustion. The result can be summarized as follow. The ignition occurs at the position that is closed to the surface of the cloud. Maximum temperature and velocity appear at ignition point, and the concentrations of gaseous fuel and oxidizer decrease rapidly near the ignition point. The chemical reaction takes place in wider zone as number density and particle radius decrease. The ignition delay is shortest when particle radius is about $50\;{\mu}m$, and tends to be shorter as number density and initial ambient temperature increase.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.49-51
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• 2015

In this research, engine performance and emission variation according to equivalence ratio and ignition time is calculated by validated analysis model. LNG engine ignite by spark plug and spark ignition modeled using DPIK model and G-equation that modeled initial flame surface called kernel and velocity and position of flame front. Engine pressure and emission was validated with experimental data.

• 한국자동차공학회논문집
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• 제6권3호
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• pp.115-122
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• 1998

For digital engine control timings, such as ignition, are based on the crank shaft angle. Therefore, it is very important that the angle of the crank shaft can be detected with accuracy for optimal ignition timing. Sequential multi-point injection(MPI) systems that have independent injection events for each cylinder, are used to inject an accurate quantity of fuel, and to cope with varying engine status promptly. In this study the distributorless ignition timing. A crankshaft position sensor has been installed such that it generates a number of pulses per crankshaft revolution to permit accurate detection of the crank shaft angle. An event detecting algorithm has been developed, which detects the crank shaft pulses generated by the position sensor, and the software outputs the required control signals at given crank angle values. We clarified that the hardware method is the best way to increase the performance of the control system, because the event detecting duration T(1+2)max becomes zero.

• 대한기계학회논문집B
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• 제35권5호
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• pp.451-457
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• 2011

본 연구의 주 목적은 연료 수분 미소 정량 공급기를 장착한 층류 반응기(LFR)에서 수분함량 변화에 따른 석탄의 휘발분 점화 특성을 조사하는 것이다. 실제 발전소의 미분기 출구 분위기와 비슷한 수분량이 석탄량의 20, 30, 40%로 LFR에 석탄과 함께 공급했을 때 휘발분의 점화 위치와 시간을 실험적으로 관찰하였다. 석탄이 공급되는 층류 반응기 정 중앙의 수직방향으로 $70{\mu}m$ R-type 열전대를 이용하여 복사 열손실을 고려한 가스온도를 측정하였고, 휘발분 점화 위치는 CCD 카메라를 이용해 촬영한 15~20개의 이미지를 디지털 이미지 프로세싱을 통해 얻은 평균 값으로 결정하였다. 그 결과 수분량이 증가할수록 가스 온도는 감소하였고, 점화 위치는 2.92, 3.36, 3.96, 4.65mm로 지수적으로 증가하였다. 이러한 실험결과는 이론적으로 adiabatic thermal explosion에서의 점화 지연 시간과 같은 경향을 나타내었다.

• 대한기계학회논문집B
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• 제22권3호
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• pp.294-302
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• 1998

Ignition characteristics of a vertical solid fuel plate with block have been investigated experimentally. For low radiant heat flux, ignition does not occur in a vertical solid fuel plate without block. In the case with the block on a vertical fuel plate, however, ignition can occur by increasing the residence time and the time to absorb the incident radiation flux by fuel vapor in gas phase. The ignition occurs below block and the point varies according to the block location and the block height. As the block height increases, the block locates at higher position, and the hot wall temperature increases, the ignition delay time decreases. Also as the initial temperature of fuel plate rises, the ignition delay time of the solid fuel plate decreases. The temperature distribution of solid fuel plate with block is nearly proportional to the radiant heat flux distribution. Therefore, the effect temperature by natural convection heat transfer is of the same order as that of inhibition of temperature increase by pyrolysis.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.864-870
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• 2001

Flame propagation along vortex tube was experimentally investigated. The vortex tube was generated by the ejection of propane from a nozzle through a single stroke motion of a speaker and the ignition was induced from a single pulse laser. Non-reactive flow fields were visualized using shadow technique. From these images, vortex ring size and translational velocity were measured in order to determine the ignition time and position. Flame structure and flame speed were measured using high speed CCD camera. Flame speed was accelerated during the initial stage of flame kernel growth, and reached near constant value during steady propagation period. Near the completion of propagation, flame speed was decelerated and then extinguished. Flame speed along the non-premixed vortex tube was found to be linearly proportional to circulation, which was similar to that of the flame propagation along premixed vortex ring. Ignition position minimally affects the propagation characteristics. These imply that flame is propagating along the maximum speed locus expected to be along stoichiometric contour and also support the existence of tribrachial flames.