• 한국추진공학회지
• /
• 제21권4호
• /
• pp.79-88
• /
• 2017

램젯 연소실 조건에서 점화보조제가 도포된 Fuel-rich 추진제의 점화 실험을 수행하여 점화 지연과 연소 유지를 확인하였다. 연료 그레인은 HTPB에 AP 파우더 15 wt.%, Al 파우더 5 wt.%가 혼합된 형태로 구성되어 있다. 한편 연료 그레인에 $NC/BKNO_3$와 Composite 추진제로 이루어진 점화보조제를 도포하여 빠른 점화지연이 나타나도록 하였다. 에탄올 블렌딩 과산화수소 가스발생기를 통해 램젯 연소실의 공기와 가깝도록 온도, 압력, 산소 조성을 조절한 산화제 가스를 유속 $200kg/m^2s$으로 공급하였다. 실험 결과, 점화보조제가 잘 작동하여 연료그레인에서 0.6초의 점화 지연시간을 파악하였고 연소 중에는 화염이 유지되는 것을 확인하였다.

• 한국추진공학회지
• /
• 제22권4호
• /
• pp.85-90
• /
• 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.

• Bulletin of the Korean Chemical Society
• /
• 제25권2호
• /
• pp.293-297
• /
• 2004

The ignition of monomethylamine was studied in reflected shock waves over the temperature range of 1255- 1579 K and the pressure range of 1.04-1.51 bar. The ignition delay time was measured by the sudden increase of pressure profile and the radiation emitted by OH radicals. The relationship between the ignition delay time and the concentrations of monomethylamine and oxygen was determined in the form of mass-action expressions with an Arrhenius temperature dependence. In contrast to the behavior observed in hydrocarbons, monomethylamine acts to accelerate rather than inhibit its own ignition. And numerical modeling of the ignition of $CH_3NH_2$ has also been carried out to test the several kinetic mechanisms.

• 오토저널
• /
• 제11권5호
• /
• pp.55-64
• /
• 1989

The effect of discharge have been investigated for condition of spark in a multiple spark ignition engine, as the spark duration, capacitive and inductive discharge energy were calculated for condition of spark by ignition wave and energy formula. The useful portion of spark discharge is divided into capacitance portion and inductance portion. It was found that capacitive discharge energy and spark duration were increased according to increasing number of spark, and inductive discharge energy was increased according to increasing spark interval. Therefore engine torque was increase and lean misfire limit was extended comparing with the standard ignition system. It found that spark energy was discharged within ignition delay period availability acted on the formation and growth of flame kernel, and total spark energy was increased according to increasing number of spark times, but discharged spark energy after ignition delay became unavailable energy. And the capacitive discharge energy has the dominant effect for stoichiomeric or not very rich air-fuel mixture but inductive discharge energy has the dominant effect for lean air-fuel mixture.

• 한국연소학회지
• /
• 제18권4호
• /
• pp.21-28
• /
• 2013

HCCI engines have mainly focused on achieving low temperature combustion in order to obtain higher efficiency and lower emission. One of practical difficulties in HCCI combustion is to control the start of combustion and subsequent combustion phasing. The choice of primary reference fuels in HCCI strategy is one of various promising solutions to make HCCI combustion ignition-controlled. The behavior of ignition delay to the frequency variation of sinusoidal velocity oscillation is computationally investigated under HCCI conditions of PRF75 using a reduced chemistry in a counterflow configuration. The second-stage ignition is more delayed as the higher frequency is imposed on nozzle velocity fluctuation whereas the first-stage ignition is not much influenced.

• 한국자동차공학회논문집
• /
• 제9권4호
• /
• pp.44-49
• /
• 2001

Reduced chemical kinetics mechanism has been derived, which can be applicable for autoignition model of hydrocarbon fuels, and contains 23 reactions and 18 species. The present model is validated with the experimental data, where the ignition delays of several hydrocarbon fuels, such as n-heptane, i-octane, n-decane and DME(dimethylether) are measured as equivalence ratios are varied. Especially, the effects of different fuels on ignition delays can be explained by changing the rate constants of three reactions among the present model. As a result, the proposed model can be applicable to two stage ignition model of Diesel combustion.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2010년도 제35회 추계학술대회논문집
• /
• pp.705-706
• /
• 2010

킥모터 점화기의 점화 초기 연소 특성에 대한 설계 해석 결과 초기 압력 조건에 따라 100~500 ms 범위의 점화지연이 생기는 것으로 나타났다. 개발 시험에서 점화기가 점화 초기 주 추진제를 점화시키는데 충분한 에너지를 공급할 수 있다는 것을 검증하였다.

• 한국분무공학회지
• /
• 제3권1호
• /
• pp.19-26
• /
• 1998

The effect of mixture component makes a nelay time and a long total combustion period $\tau_{p\;max}$. The flame propagation delay $\tau_{df}$ was determined by the record of current ion. The pressure release delay $\tau_{dp}$ and $\tau_{p\;max}$ were determined by the indicated pressure diagram in constant volume of the combustion chamber. The results are as follows: 1) The ignition delay $\tau_t$ time takes the minimum value around $\Phi=1.15$. 2) $\tau_{df}$ and $\tau_t$ time increased according to the increases of the concentrated dilution gases, because the adiabatic flame temperature decreased due to the increases of the heat capacity. But dilution gases have little effect on flame nucleus formation delay 3) The relation between $\tau_t$ time and reciprocal laminar burning velocity is almost linear. 4) The increase of the propagation length is accompanied with increased ratio of the $\tau_{df},\;\tau_{dp},\;\tau_{t},\;\tau_{p\;max}$.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 1995년도 제5회 학술강연회논문집
• /
• pp.139-144
• /
• 1995

The main purpose of igniter is sure ignition of main propellant at desired ignition delay times. Since ignition mechanism of solid rocket propellant involves so many complicated physical and chemical phenomena, it is almost impossible to predict ignition behavior with pure analytical means. In this study, one dimensional and unsteady ignition transient phenomena in solid rocket was analyzed by finite volume method. In analysis, assumption was made that ignition occurs when propellant surface temperature reaches to it's auto-ignition temperature.

• 한국가스학회지
• /
• 제17권2호
• /
• pp.21-27
• /
• 2013

화재 및 폭발 방호를 위해서 문헌에서의 최소자연발화온도 값을 사용하는 것이 일반적이다. 본 연구에서, n-Propanol+n-Octane 계의 최소자연발화온도는 ASTM E659 장치를 이용하여 발화지연시간으로부터 측정하였다. 2성분계를 구성하는 n-Propanol과 n-Octane의 측정된 최소자연발화온도는 각 각 $435^{\circ}C$와 $218^{\circ}C$ 였다. 그리고 두 개의 2성분계에서 측정된 발화지연시간은 제시된 식에 의한 예측된 발화지연시간과 적은 평균절대오차에서 일치하였다.