• 한국분무공학회지
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• 제19권3호
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• pp.109-114
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• 2014

The main purpose of this study is to provide basic information of droplet burning, extinction process and flame behavior of methanol fuel and improve the ability of theoretical prediction of these phenomena. For the improved understanding of these phenomena, this paper presents the experimental results on the methanol droplet combustion conducted under various initial droplet diameters ($d_0$), ambient pressure ($P_{amb}$), and oxygen concentration ($O_2$) conditions. To achieve this, the experimental study was conducted in terms of burning rate (K) with normalized droplet diameter ($d/d_0$), flame diameter ($d_f$) and flame standoff ratio (FSR) under the assumptions that the droplet combustion can be described by both the quasi-steady behavior for the region between the droplet surface and the flame interface and the transient behavior for the region between the flame interface and ambient surrounding.

• 대한기계학회논문집B
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• 제23권1호
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• pp.114-122
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• 1999

Reignition as special cases of acoustic pressure responses of flame are numerically studied by employing methanol droplet flame as a laminar flamelet. Quasi-steady flame responses occur in the range of small amplitude, low frequency oscillation. Reignition phenomena can occur when, by increasing the frequency of large amplitude acoustic pressure, the magnitude of characteristic acoustic time is the same order of that of characteristic reaction time of flames. And more increasing of amplitude of acoustic pressure induces the direct extinction of flame. Flame can sustain its own intensity even under the steady extinction temperature in case of high frequency acoustic oscillation, and this tendency is remarkable with increasing frequency. Reignition regime with respect to amplitude and frequency of acoustic pressure doesn't exist in low frequency($10^2$ Hz, in this study), but broadens with frequency of acoustic pressure.

• 대한기계학회논문집
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• 제18권2호
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• pp.389-396
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• 1994

It is very important to clarify the ignition and flame propagation processes of methanol fuel in the Spark-ignition engine. High speed Schlieren photography and pressure trace analyses were used to study on combustion characteristics of methanol fuel in a constant volume chamber. Methanol-air mixtures equivalence rations from lean limit to 1.4 were ignited at initial pressure (0.1, 0.3, 0.5 MPa), temperature (313 343, 373 K) and ignition energy (40, 180 mJ). As the result of this study, we verified the characteristics such as ignition delay, effective thermal efficiency, flame propagation velocity, lean limit, ignitability and combustion duration. Obatained results are as follows. (1) The time to 10% reach of maximum pressure was 40-50% of the total combustion duration for this experimental condition hardly affected by equivalence ratio. (2) The Effective thermal efficiency, as calculated from maximum pressure was the highest when the mixture was slightly lean $({\phi} 0.8-0.9)$ and maximum pressure was the highest when the mixiture was slightly rich $({\phi} 1.2-1.2).$

• 한국안전학회지
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• 제25권6호
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• pp.103-108
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• 2010

In this study, tank truck incidents of road transport of hazardous materials to experimental investigated the potential fire hazard. Real scale fire was to perform experiments for on this qualitative and quantitative data collection and analysis. Particularly affected by radiant heat from the flames caused and damage estimates range investigated accordingly. Flame temperature, internal temperature of tank and emitted radiation from the flames was investigated. The flame of light oil spill caused a fire at a temperature of about $300^{\circ}C$ high in comparison with the methanol by combustion of diesel and methanol, according to the difference, the flame duration changes varies depending on the Burning rate, amount of radiant heat flux from light oil fire was 4 times increases compared with fire of methanol. Depending on spill locations(kinds of road surfaces, absorbing rate) and the longer the duration of the flame important factors for the internal temperature of tank truck rise was found. Dirt roads than paved road accident in a fire caused by leakage of hazardous was could the higher the damaged. Therefor, Fire suppression activities should be required in particular to be around.

• 한국안전학회지
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• 제31권5호
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• pp.54-60
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• 2016

In this study, tank truck incidents of road transport of hazardous materials to experimental investigated the potential fire hazard. Real scale fire was to perform experiments for on this qualitative and quantitative data collection and analysis. Particularly affected by radiant heat from the flames caused and damage estimates range investigated accordingly. Flame temperature, internal temperature of tank and emitted radiation from the flames was investigated. The flame of light oil spill caused a fire at a temperature of about $300^{\circ}C$ high in comparison with the methanol by combustion of diesel and methanol, according to the difference, the flame duration changes varies depending on the Burning rate. Depending on spill rate(30, 60, 90 and $120{\ell}/min$) and the longer the duration of the flame important factors for the internal temperature of tank lorry rise was found. Road accident in a fire caused by leakage of hazardous was could the higher the damaged. Therefor, Fire suppression activities should be required in particular to be around.

• 수산해양기술연구
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• 제21권2호
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• pp.157-166
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• 1985

가변 압축비 기관(C. F. R.)에 ionization gap probe를 피스톤 및 실린터 헤드 sleeve에 설치하여 화염거동에 대하여 실험한 결과는 다음과 같다. 1) 혼합연료에서 화염전파속도는 메타놀 함량에 따라 증가한다. 2) 혼합연료에서 메타놀 percent가 증가하면 에너지 소모비 (Btu/HP-hr)가 감소하여 열효율은 증가한다. 3) 당량비가 일정하면 평균유효압력은 메타놀 량이 증가할수록 감소한다. 4) 순수한 가솔린 및 혼합연료는 점화진각이 클수록 NO 하(X) 방출량은 증가하고 희박 혼합기 영역에서 NO 하(X) 방출량은 최대가 된다. 또 RG50/M40/THF10/W1의 연료에서는 당량비가 0.95이하에서는 당양비가 낮을수록, 점화진각이 높을수록 NO 하(X) 방출량은 증가하고, 0.95 이상에서는 당량비와 점화진각이 클수록 방출량은 감소한다. 5) CO, HC의 최소값은 메타놀 함유량이 높을수록 감소한다.

• 한국화재소방학회논문지
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• 제26권3호
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• pp.73-78
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• 2012

화점높이 변화에 따른 풀 화재와 회오리 화염의 연소특성을 알아보기 위하여 인화성 액체인 메탄올을 $100{\times}100{\times}50$ 크기의 스테인레스 재질의 사각형 용기에 넣고 연소실험을 하였다. 연소시간, 질량감소속도, 화염온도, 화염높이 및 외부로부터 화염으로의 공기유입속도 등을 측정하였으며, 연소시 화염의 거동은 비디오카메라를 이용하였다. 모든 실험결과로부터 화점높이 변화에 따른 연소특성은 풀 화재보다는 회오리 화염에 있어서 더 큰 영향을 준다는 것을 알 수 있었다.

• Journal of Mechanical Science and Technology
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• 제20권9호
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• pp.1459-1474
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• 2006

The present study is focused on the development of the RIF (Representative Interactive Flamelet) model which can overcome the shortcomings of conventional approach based on the steady flamelet library. Due to the ability for interactively describing the transient behaviors of local flame structures with CFD solver, the RIF model can effectively account for the detailed mechanisms of $NO_x$ formation including thermal NO path, prompt and nitrous $NO_x$ formation, and reburning process by hydrocarbon radical without any ad-hoc procedure. The flamelet time of RIFs within a stationary turbulent flame may be thought to be Lagrangian flight time. In context with the RIF approach, this study adopts the Eulerian Particle Flamelet Model (EPFM) with mutiple flamelets which can realistically account for the spatial inhomogeneity of scalar dissipation rate. In order to systematically evaluate the capability of Eulerian particle flamelet model to predict the precise flame structure and NO formation in the multi-dimensional elliptic flames, two methanol bluffbody flames with two different injection velocities are chosen as the validation cases. Numerical results suggest that the present EPFM model has the predicative capability to realistically capture the essential features of flame structure and $NO_x$ formation in the bluff-body stabilized flames.

• 수산해양기술연구
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• 제26권3호
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• pp.288-294
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• 1990

혼합연료의 혼합성에서 보았을 때, #6 오일은 메타놀, 에타놀, 프로파놀등 어느 알콜과도 혼합하지 않고 급격한 분리 현상을 일으켰으며, #1 오일과 메타놀의 혼합에서도 알콜 함량이 매우 낮을 때를 제외하고는 거의 혼합되지 않았다. 에타놀과 프로파놀만이 #1 오일과 균일한 상태(homogeneous condition)로 혼합되었다. 인화점은 알콜 함량의 증가에 의해 급격히 하락하다가 알콜 함량 20% 이상에서 순수한 알콜과 차이를 보이지 않았으며, 점성은 에타놀 혼합의 경우는 혼합비의 증가에 따라 완만히 감소하였으나, 프로파놀의 경우는 증가하였다. 화염의 용적은 알콜 증가에 따라 감소하고 길이도 짧아졌으나 에타놀 혼합체의 경우에만 예외를 나타내었으며, 휘도도 알콜 증가에 따라 눈에 띄게 감소하였다.

• 오토저널
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• 제13권5호
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• pp.89-94
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• 1991

In the quantitative analysis of oxygenated exhaust emissions (unburned methanol, formal- dehyde) from methanol fueled vehicles, the oxygen contained in oxygenated exhaust gases lowers the FID (Flame Ionization Detector) response factor of conventional THC analyzer and leads to erroneous HC reading. For correct measurement of various HCs including oxygenated HCs emitted from FFV(Flexible Fuel Vehicle), first of all, the measurement technique of real HC emissions should be established. GC and HPLC-DNPH measuring methods specified by the EPA are used in this paper to analyze unburned methanol and formaldehyde components in the exhaust emissions. In emission test of FFV, unburned methanol and formaldehyde are emitted mostly during cold transient period, and it is shown that formaldehyde emission level is proportional to engine displacements. In view of the HC emission level, vehicle using M85 has 40% advantage over gasoline-fueled vehicle in OMHCE and has a good potential of a low emission vehicle.