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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Society of Combustion
Journal Basic Information
Journal DOI :
The Korean Society of Combustion
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Volume & Issues
Volume 17, Issue 4 - Dec 2012
Volume 17, Issue 3 - Sep 2012
Volume 17, Issue 2 - Jun 2012
Volume 17, Issue 1 - Mar 2012
Selecting the target year
Combustion Characteristic of Anode Off Gas for Fuel Cell Reformer
Lee, Pil Hyong ; Hwang, Sang Soon ;
Journal of the Korean Society of Combustion, volume 17, issue 4, 2012, Pages 5~10
The reformer system is a chemical device that drives the conversion of hydrocarbon to hydrogen rich gas under high temperature environment(
). Generally, NG(Natural Gas) or AOG(Anode Off Gas) is used as fuel of fuel cell reformer combustion system. The experimental study to analyze the combustion characteristics of a premixed ceramic burner used for 0.5-1.0 kW fuel cell reformer was performed. Ceramic burner experiments using NG and AOG were carried out to investigate the flame stability characteristics by heating capacity, equivalence ratio and different fuels respectively. The results show that surface flames can be classified into green, red, blue and lift-off flames as the equivalence ratio of methane-air mixture decreases. And the stable flames can be established using NG and AOG as reformer fuel in the perforated ceramic burner. In particular, the blue flame is found to be stable at a lean equivalence ratio under different mixture conditions of NG and AOG for the 0.5 to 1.0 kW fuel cell system power range. NOx emission is under 60 ppm between 0.70 to 0.78 of equivalence ratio and CO emission is under 50 ppm between 0.70 to 0.84 of equivalence ratio.
Control the Blow-off Characteristics of Lean Premixed Flames Utilizing a Stratified Flame Concept
Lee, Wonnam ; Ahn, Taekook ; Nam, Younwoo ;
Journal of the Korean Society of Combustion, volume 17, issue 4, 2012, Pages 11~20
The Blow-off characteristics of LPG/air lean pre-mixed flames were experimentally investigated using a double and a multiple concentric coflow burners. Experiments were conducted to understand the effects of recirculation motion, thermal interaction between flames, and stratified flame configuration. Here, the stratified premixed flame is a "new concept" of a flame that sequentially contains fuel rich, stoichiometric, and fuel lean reaction zones in a flame. The blow-off from a lean premixed flame was significantly suppressed with recirculation motion. The recirculation motion by itself, however, was not sufficient to prevent the blow-off when the equivalence ratio became low. The existence of a inner premixed flame could also help to prevent the blow-off of lean premixed flame; however, the blow-off suppression effect was rather diminished by weakened recirculation motion with the presence of inner flame. The inner flame could be separated from an outer flame on a multiple concentric coflow burner, causing recirculation motion as well as thermal interaction between flames to become effective; therefore, the blow-off was further suppressed. The lean premixed flame could be stabilized with a fuel rich premixed flames that was produced with the supply of fuel through an inner nozzle. The penetration of lean premixed gas from outside into the fuel stream produced a lifted rich premixed flame. Chemiluminescence images of OH, CH, and
radicals confirmed the structure of a stratified premixed flame. The stable premixed flames could be obtained at the very fuel lean condition by applying the stratified premixed flame concept.
Overview of Fire Safety onboard International Space Station(ISS): Characteristics of Flame Ignition, Shape, Spread, and Extinction in Microgravity
Park, Seul-Hyun ; Hwang, Cheol-Hong ;
Journal of the Korean Society of Combustion, volume 17, issue 4, 2012, Pages 21~29
Due to a significant leap in the science and technology, the manned space exploration that has started with suborbital flights is now being expanded into the deep space. The space superpowers such as the U.S. and Russia have been making an effort to further develop the manned space technology. Among such technologies, the fire safety technology in microgravity has recolonized as one of the most critical factors that must be considered for the manned space mission design since the realistic fire broke out onboard the Mir station in 1997. In the present study, the flame characteristics such as flame ignition, shape, spread, and extinction that are critical to understand the fire behavior under microgravity conditions are described and discussed. The absence of buoyancy in microgravity dominates the mass transport driven by diffusiophoretic and thermophorectic fluxes (that are negligible in normal gravity) and influences the overall flame characteristics-flame ignition, shape, spread, and extinction. In addition, the cabin environments of the pressurized module (PM) including the oxygen concentration, ambient pressure, and ventilation flow(which are always coupled with microgravity condition during the ISS operation) are found to be the most important aspects in characterizing the fire behavior in microgravity.
Flame Length and EINOx Scaling of Syngas
/CO Turbulent Non-premixed Jet Flames
Hwang, Jeongjae ; Sohn, Kitae ; Bouvet, Nicolas ; Yoon, Youngbin ;
Journal of the Korean Society of Combustion, volume 17, issue 4, 2012, Pages 30~37
The flame lengths and NOx emission characteristics of syngas
/CO turbulent non-premixed jet flames were investigated. The flame length which is the main parameter governs NOx emission was studied for various syngas compositions. The flame length was compared with previous correlation between Froude number and flame height and it shows that they have good agreements. It was confirmed that the turbulent jet flames herein investigated are in the region of buoyancy-momentum transition. NOx emission was reduced with increased Reynolds number and CO contents in syngas fuel and with decreased fuel nozzle diameter which is attributed by decreased flame residence time. Previous EINOx scaling based on flame residence time of
satisfies only the jet flame in momentum-dominated region, not buoyancy-momentum transition region. The simplified flame residence time (
) was adopted in modified EINOx scaling. The modified scaling satisfies the jet flames not only in momentum-dominated region but in buoyancy-momentum transition region. The scaling is also satisfied with
/CO syngas jet flames.
Experimental Study on Extinction Behavior in Buoyancy-minimized Counterflow Diffusion Flame
Chung, Yong Ho ; Park, Jeong ; Kwon, Oh Boong ; Yun, Jin-Han ; Kee, Sang-In ; Kim, Young Ju ;
Journal of the Korean Society of Combustion, volume 17, issue 4, 2012, Pages 38~43
Experimental study was conducted to elucidate flame extinction phenomena in counterflow flame. Using a curtain helium flow significantly reduced buoyancy such that the flame can be positioned at the center between the upper and lower nozzles even at the velocity ratio of 1.0. The curves of critical diluent mole fraction versus global strain rate have C-shapes. The flame oscillation was observed prior to low strain rate flame extinction at both flame conditions with and without minimizing buoyancy force. The results show that, at low strain rate flame, the self-excitation frequency with the order of 1.0 Hz in the case of utilizing pure helium gradually decreases in increase of
mole fraction in the curtain flow, meaning that buoyancy suppresses the self-excitation of the outer edge flame.
Experimental Study on Effects of Syngas Addition in Flame Propagation and Stability of DME-Air Premixed Flames
Song, Wonsik ; Park, Jeong ; Kwon, Ohboong ; Yun, Jinhan ; Kee, Sangin ;
Journal of the Korean Society of Combustion, volume 17, issue 4, 2012, Pages 44~50
The present study was conducted to investigate the flame instability(evaluated by Markstein length and cellular instability) and laminar burning velocity in a constant volume combustion chamber at room temperature and elevated pressure up to 0.3 MPa to suggest the possibility of utilizing mixtures of syngas added DME-air premixed flames in internal combustion engines. The experimentally measured laminar burning velocities were compared to predictions calculated the PREMIX code with Zhao reaction mechanism. Discussions were made on effects of syngas addition into DME-Air premixed flames through evaluating laminar burning velocity, Markstein length, and cellular instability. Particular concerns are focused on cellular instability caused by hydrodynamic instability and diffusive-thermal instability.
Helieum-dilution Effect of Coflow Air on Self-excitation in Laminar Coflow Jet Flames
Lee, Won June ; Park, Jeong ; Kwon, Oh Boong ; Baek, Se Hyun ; Ko, Sung Ho ;
Journal of the Korean Society of Combustion, volume 17, issue 4, 2012, Pages 51~59
Experimental study in coflow jet flames has been conducted to investigate the helium-dilution effect of coflow air on self-excitation. For various helium mole fractions and jet velocities, two types of self-excitation were observed: buoyancy-driven self-excitation and Lewis-number-induced self-excitation(here after called Le-ISE) coupled with buoyancy-driven one. The difference between buoyancy-driven and Le-ISE is clarified by using the Mie-scattering visualization as well as exploring the different features. The mechanism of Le-ISE is proposed. When the system Damk
hler number was lowered, Le-ISE is shown to be launched. Le-ISE is closely related to heat loss, in that it can be launched in even methane jet flame (Lewis number less than unity) with helium-diluted coflow air. Particularly, Le-ISE becomes significant as the Damk
hler number decreases and heat-loss becomes significant.
Computational Study of the MILD Combustion and Pollutant Emission Characteristics in Jet Flow Field
Kim, Yu Jeong ; Song, Keum Mi ; Oh, Chang Bo ;
Journal of the Korean Society of Combustion, volume 17, issue 4, 2012, Pages 60~65
The MILD combustion and pollutant emission characteristics were investigated computationally. The temperature of supplying air-stream and mixing rate (
) of exhaust gas in the air-stream were adjusted to investigate the effects of those parameters on the MILD combustion in jet flow field. The emission indices for NO (EINO) and CO (EICO) were introduced to quantify the amount of those species emitted from the combustion. The high-temperature region disappeared gradually as the mixing rate increased for fixed air-stream temperature. The EINO increased as the air-stream temperature became higher for fixed mixing rate, and the EINO decreased dramatically with increasing the mixing rate for each air-stream temperature condition. The EICO also decreased with increasing the mixing rate and it was nearly independent of air-stream temperature except for near
= 0.7. It was found that the CO supplied in the air-stream can be destroyed in the MILD combustion over the certain mixing rate.