• 한국연소학회지
• /
• 제13권3호
• /
• pp.9-16
• /
• 2008

In this study, a cylindrical constant volume combustion chamber is used to investigate the flow and combustion characteristics of methane-air homogeneous mixture under various initial charge pressure, excess air ratios and ignition times. The flame and burning speed, mean gas speed are calculated by numerical analysis to analyze the combustion characteristics. It is found that the mean gas velocity during combustion has the maximum value around 300 ms and then decreased gradually on the condition of 10000 ms, and that the combustion duration is shorten and flame speed and burning velocity have the highest value under the conditions of an excess air ratio 1.1, an initial charge pressure of 0.2 MPa and an ignition time of 300 ms in the present study. And, the initial pressure and burning speed are in inverse proportion, so that it is in agreement with Strehlow who presented that the initial pressure and burning speed are in inverse proportion when the burning speed is under 50cm/s.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
• /
• pp.207-210
• /
• 2014

The potential of combustion treatment of low concentration VOC on a turbulent partially premixed flame has been studied experimentally. The significant decrease in hydrocarbon concentration from the low concentration VOC was observed with a turbulent partially premixed flame. The VOC/inert gas mixture whose fuel concentration is beyond the flammability limit could be treated in this method.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
• /
• pp.85-86
• /
• 2014

The characteristics of the outward-propagating premixed flames of stoichiometric mixtures of R134a/methane/oxygen/nitrogen have been experimentally investigated in a constant volume combustion chamber. Three regimes of the expanding flames were categorized based on the flame behavior.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
• /
• pp.787-790
• /
• 2017

본 연구는 이원추진제 추력기(thruster)에 사용되는 메탄-산소 연소특성규명의 선행연구로서 모델연소실 내 전단동축형인젝터를 통해 분사된 기체메탄-기체산소 비예혼합화염의 연소안정한계 및 화염형상을 도출하기 위한 실험적 연구가 수행되었다. DSLR 카메라를 이용하여 화염 직접이미지(direct image)를 촬영하였고, 이미지 후처리(post-processing)를 통해 연소특성파악 및 화염길이 정량화를 수행하였다. 그 결과, 산화제 레이놀즈 수($Re_o$)가 증가함에 따라 이론반응비(stoichiometric ratio)에서 안정된 화염이 발생하였고, 동일 인젝터직경 조건에서 난류화염의 길이가 늘어남을 확인하였다.

• 한국연소학회지
• /
• 제8권4호
• /
• pp.15-23
• /
• 2003

The zone conditional two-fluid equations are derived and validated against DNS database of a premixed turbulent flame. The conditional statistics of major flow variables are investigated to understand the mechanism of flame generated turbulence. The flow field in burned zone shows substantially increased turbulent kinetic energy, which is highly anisotropic due to reaction kinematics across thin f1amelets. The transverse component may be larger than the axial component for a distributed pdf of the flamelet orientation angle, while the opposite occurs due to redistribution of turbulent kinetic energy and flamelet orientation normal to the flow at the end of a flame brush. The major source or sink terms of turbulent kinetic energy are the interfacial transfer by the mean reaction rate and the work terms by fluctuating pressure and velocity on a flame surface. Ad hoc modeling of some interfacial terms may be required for further application of the two-fluid model in turbulent combustion simulations.

• 한국연소학회지
• /
• 제20권4호
• /
• pp.1-9
• /
• 2015

The object of this study is a deriving the relations according to the measuring locations between the chemiluminescence and the flame state at commercial burner. In this study, the flame chemiluminescence of the flame of commercial burner is measured using a photomultiplier tube and the optical band-pass filter. In addition, the contour of the chemiluminescence of the flame is measured using the common CCD camera and the optical band-pass filters, and the acquired images is converted by the simple image processing as a matrix form. The results showed that certain relationship between optical data and equivalence ratio exists, and the contour according to the measuring location of the flame chemiluminescence is different by equivalence ratio.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
• /
• pp.319-320
• /
• 2015

This study is aiming to establish the relationship between the optical signal of flame through an optical fiber and the equivalent ratio of flame. In this experiment, flame optical signal in a furnace is measured using photodiode. The combustion system is composed of 15W turbulent burner and industrial boiler, and flame chemiluminescence is measured at various experimental conditions. In this study, the flame chemiluminescence of turbulent premixed flame is measured using commercially available photodiode. It is experimentally investigated the relationship between equivalent ratio and photodiode signal.

• 조명전기설비학회논문지
• /
• 제25권5호
• /
• pp.79-84
• /
• 2011

In this study, breakdown characteristics of a vertical sphere-plane air gap in the presence of combustion flame were examined under the application of a.c. and d.c. high-voltages in order to investigate the effect of flame on the dielectric strength of air. Propane gas is used as the fuel of the flame, and the temperature distribution of air around the flame is measured. The polarity effects for the d.c. voltages and breakdown voltages of air when applied both of a.c. and d.c. voltages were examined in the case of the variation of the gap length and the horizontal distance between the flame and the high-voltage sphere electrode. The influence of relative air density, electrification and shape changes of the flame as factors that affect the breakdown voltages were discussed.

• 한국추진공학회지
• /
• 제21권3호
• /
• pp.41-48
• /
• 2017

전단 동축형 인젝터를 통해 분사된 친환경 이원추진제 기체메탄-기체산소의 연소특성을 규명하기 위한 연구를 수행하였다. DSLR카메라를 이용하여 다양한 연소조건에서 화염을 촬영하였고, 이미지 후처리 기법을 통해 화염형상을 정량화한 후 그 특성을 분석하였다. 안정화 관점에서 확산화염은 anchored flame regime과 blow-off regime으로 구분될 수 있었으며, 산화제 레이놀즈 수($Re_o$)가 증가함에 따라 부착화염의 형성, 화염의 길이가 증가하는 경향을 나타냈다. 본 실험에 이용된 전단 동축형 인젝터는 추진제 제트의 운동량 확산에만 종속하고 그리 양호하지 않은 혼합으로 인해 분사방향으로 길이가 긴 화염을 형성하게 되므로 보다 큰 연소실 길이직경비가 요구됨을 확인할 수 있었다.

• 한국연소학회지
• /
• 제22권2호
• /
• pp.19-26
• /
• 2017

An experimental study investigates the flame response characteristics of jet-diffusion flame and premixed flame. The experiment was conducted while varying the amplitude. Flame lengths were quantified for OH chemiluminescence measurement and compared with the result of the flame transfer function. Flame length and flame velocity perturbation were normalized and compared with the result of the flame transfer function. The comparison results appear that velocity perturbation and flame length oscillation of premixed flame show linear behaviors on the other hand jet-diffusion flame, amplitudes are more thant 0.20, shows nonlinear behaviors of flame velocity perturbation and flame length oscillation.