• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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• pp.177-180
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• 2010

혼합비와 연소압에 따른 이중 와류 동축 분사기의 유량계수 변화를 살펴보았다. 연료 과농 조건에서 액체산소와 케로신을 이용하여 이중 와류 동축 분사기의 연소시험을 수행하였다. 두 종류의 분사기가 시험에 적용되었는데, 산화제 분무각 변화에 의한 추진제간 모멘텀 비 차이와 연료 노즐 직경 차이로 인한 유량계수 영향 특성이 파악되었다. 연료 와류실을 연료가 모두 채운 상태에서 연소가 이루어지는 경우 화염 구조의 변화가 없어 혼합비에 다른 유량계수 변화 또한 보이지 않는 것으로 파악하였다.

• Advances in Energy Research
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• 제4권3호
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• pp.213-221
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• 2016

The main purpose of this work is to test the validation of use of a four step reaction mechanism to simulate the laminar speed of hydrogen enriched methane flame. The laminar velocities of hydrogen-methane-air mixtures are very important in designing and predicting the progress of combustion and performance of combustion systems where hydrogen is used as fuel. In this work, laminar flame velocities of different composition of hydrogen-methane-air mixtures (from 0% to 40% hydrogen) have been calculated for variable equivalence ratios (from 0.5 to 1.5) using the flame propagation module (FSC) of the chemical kinetics software Chemkin 4.02. Our results were tested against an extended database of laminar flame speed measurements from the literature and good agreements were obtained especially for fuel lean and stoichiometric mixtures for the whole range of hydrogen blends. However, in the case of fuel rich mixtures, a slight overprediction (about 10%) is observed. Note that this overprediction decreases significantly with increasing hydrogen content. This research demonstrates that reduced chemical kinetics mechanisms can well reproduce the laminar burning velocity of methane-hydrogen-air mixtures at lean and stoichiometric mixture flame for hydrogen content in the fuel up to 40%. The use of such reduced mechanisms in complex combustion device can reduce the available computational resources and cost because the number of species is reduced.

• 오토저널
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• 제7권4호
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• pp.49-56
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• 1985

This study consists of instrumenting and running tests on variable compression engines and measuring the following combustion characterics: (a)flame speed, (b) emission and (c)performance parameter such as power and economy. The results were as follows: 1) The phase separation diagram of substitute fuels were obtained from phase separation experiment. 2) The flame propagation speed of substitute fuels were higher than gasoline and increased with increasing methanol weight percent of substitute fuels. 3) BEMP of substitute fuels was slightly less than that of gasoline but in the range of small weight percent, BEMP was compatible to gasoline. 4) Concentration of NOx decreased significantly with delaying spark advancing time. Also, it decreased for rich equivalence ratio but increased with high compression ratio. In general, NOx concentration was much lower than that of gasoline. 5) Concentration of HC and CO increased for rich equivalence ratio. Also it was lower than that of gasoline.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제27회 추계학술대회논문집
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• pp.47-53
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• 2006

산화제 과잉 예연소기는 고성능 closed cycle 액체추진로켓 시스템에 적용된다. 이러한 산화제 과잉 연소기는 산화제-연료 혼합비가 약 50이상에서 작동하므로, 예연소기에서 분무특성과 혼합성능이 연소 안정성에 큰 영향을 주게 된다 본 연구에서는 예연소기에 적용 가능한 분사기를 설계하고, 유량측정, 가시화 실험을 수행하여 예연소기 분사기의 분무특성을 연구하기로 한다.

• 한국자동차공학회논문집
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• 제5권2호
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• pp.127-135
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• 1997

Experiments have been conducted to investigate emission characteristics of compressed natural gas fueled vehicle(CNGV) by the FTP 75 mode test. Its purification technologies were also investigated. It was found that CNGV was operated on the rich A/F condition by comparison with gasoline vehicle. The Pd catalyst was higher in methane purification performance than Pt and Pd/Pt/Rh catalysts. Up to 60% portion of the accumulative HC emissions(that contains above 80% methane) form CNGV occurs during the first phase of the FTP 75 mode. CO that is exhausted at rich conditions of the air-fuel ratio more than lean conditions should be used for the catalytic reduction of NOX, because the methane is not the effective reduction for NOX in the CNGV with 3-way catalyst system.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.73-74
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• 2015

Synthesis gas such as hydrogen and carbon monoxide was produced from $CH_4/oxygen$ mixture using insulated pressurized porous media combustor. Experimentally, two cylindrical SiC foams with the different pore density were piled up in a quartz tube and fully premixed mixture was supplied in the axial direction. After stabilizing fuel-rich flame at the interface of the two foams at several pressure conditions, mole fractions of synthesis gases were measured by gas chromatography. Heat recirculation through the inner foam structure could extend the flow velocity of stable region over the laminar burning velocity. As the pressure increased, the rich flammability limit, $H_2/CO$ ratio, and module M increased.

• Journal of Advanced Marine Engineering and Technology
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• 제34권2호
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• pp.250-258
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• 2010

부상화염에서 노즐직경과 연료유량을 변화하면서 화염전파속도와 연료과농영역, 연료희박영역, 확산화염 영역에서의 체적연소반응속도의 변화 특성을 수치해석을 통하여 살펴보았다. 본 연구에서 사용한 3가지 연료노즐 직경(d=0.25, 0.30, 0.35mm)에서 연료분출속도를 증가시키면 화염전파속도가 증가하지만 변화폭은 4.3%를 넘지 않는다. 연료분출속도를 증가함에 따른 연료량 증가는 직접적이고 선형적으로 체적연소반응속도에 연관되어 있음을 알 수 있었고, 따라서 부상화염에서 연료량의 증가는 화염전파속도 보다 체적연소반응속도가 연료량 변화에 대응함을 알 수 있었다.

• 한국수소및신에너지학회논문집
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• 제28권4호
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• pp.392-400
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• 2017

An experimental study was conducted to investigate behavior of steel surface oxidation with characteristics of the combustion. The excess entalphy combustion in porous media system was applied to implement the direct radiation heating system. The surface oxidation thickness (SOT) of fuel-lean was thicker than the SOT of fuel-rich. Also, the SOT was increased by increasing residence time. Detailed explanations were given by SEM and EDS analysis.

• 대한기계학회논문집
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• 제16권1호
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• pp.70-76
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• 1992

본 연구에서는 수소와 공기의 예혼합기체가 가열된 벽면에 노출되어 있는 경 우의 점화문제를 1차원 비정상상태로 예측하고자 하며 특히, 계산에서 가정하는 화학 반응기구가 갖는 정확성에 관하여 수치해석적으로 고찰하고자 한다.

• Journal of Mechanical Science and Technology
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• 제16권12호
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• pp.1710-1718
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• 2002

The effect of fuel concentration gradient on the propagation characteristics of tribrachial (or triple) flames has been investigated experimentally in both two-dimensional and axisymmetric counterflows. The gradient at the stoichiometric location was controlled by the equivalence ratios at the two nozzles; one of which is maintained rich, while the other lean. Results show that the displacement speed of tribrachial flames in the two-dimensional counterflow decreases with fuel concentration gradient and has much larger speed than the maximum speed predicted previously in two-dimensional mixing layers. From an analogy with premixed flame propagation, this excessively large displacement speed can be attributed to the flame propagation with respect to burnt gas. Corresponding maximum speed in the limit of small mixture fraction gradient was estimated and the curvefit of the experimental data substantiates this limiting speed. As mixture fraction gradient approaches zero, a transition occurs, such that the propagation speed of tribrachial flame approaches stoichiometric laminar burning velocity with respect to burnt gas. Similar results have been obtained for tribrachial flames propagating in axisymmetric counterflow.