• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.329-334
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• 2009

An oxy-fuel boiler has been developed to capture $CO_2$ from the exhaust gas. FGR (flue gas recirculation) is adopted to be compliant with the retrofit scenario. Numerical simulations have been performed to study the detailed physics inside the combustion chamber of the boiler. The temperature field obtained from the simulation agrees with the flame image from the experiment. The FGR combustion yields similar heat transfer characteristics with the conventional air combustion while the flame is formed further downstream in case of the FGR combustion.

• Journal of Environmental Science International
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• v.27 no.5
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• pp.309-317
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• 2018

In this study, a laser sheet technique and PLIF (Planar laser-induced fluorescence) are applied to a laboratory-scale pulverized coal burner of the open type, and the spatial relationship of the pulverized coal particle zone and the combustion reaction zone is examined by simultaneous measurement of Mie scattering and OH-LIF images. It is found that this technique can be used to investigate the spatial relationship of the combustion reaction zone and pulverized-coal particles in turbulent pulverized-coal flames without disturbing the combustion reaction field. In the upstream region, the combustion reaction occurs only in the periphery of the clusters where high-temperature burned gas of the methane pilot flame is entrained and oxygen supply is sufficient. In the downstream region, however, combustion reaction can be seen also within clusters of pulverized-coal particles, since the temperature of pulverized-coal particles rises, and the mixing with emitted volatile matter and ambient air is promoted.

• Journal of the Korean Society of Combustion
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• v.22 no.4
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• pp.43-50
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• 2017

In this study, the multi-environment probability density function(MEPDF) approach has been applied to numerically investigate Delft-Jet-in-Hot-Coflow(DJHC) turbulent flames under Moderate or Intense Low-oxygen Dilution (MILD) combustion condition. Computations are made for two different jet velocities(Re = 4100 and 8800). In terms of mean axial velocity, temperature, and turbulent kinetic energy, numerical results are in reasonably good agreements with experimental data even if there exist the noticeable deviations in downstream region. Based on numerical results, the detailed discussions are made for the essential features of the non-visible flame structure and MILD combustion processes.

• 한국연소학회:학술대회논문집
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• 1998.10a
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• pp.59-67
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• 1998

The aim of this study is to investigate advantages that the catalytically supported combustor can have. For this purpose, the catalytic combustor was prepared which consisted of the catalyst bed and the thermal combustor at the downstream of the catalyst bed. The catalyst bed consisted of two-stage. Pd catalyst was installed in the first stage of the catalyst bed, and Pt catalyst was placed in the second stage. Results showed that the catalytically supported combustion had some advantages. One was that auto-ignition occurred in the thermal combustor. This can give merit that an igniter is not necessary to start flame ignition. Other was that the catalytically supported combustion was stable for lean mixture. When combustion of lean mixture was not supported by surface reaction it became unstable so that big combustion noise was created. Therefore, it is desirable to support flame by catalytic surface reaction to obtain the stable combustion of lean mixture.

• Journal of Energy Engineering
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• v.10 no.4
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• pp.379-386
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• 2001

This experimental study deals with on Nitric Oxide Formation & Reduction in Industrial Bunner. In this study, Laser-induced fluorescence (LIF) techniques have been used for quantitative measurements of Nitric Oxide. The NO A-X (0, 0) Vibrational band around 226 nm was excited using a XeCl excimer-pumped dye laser. And on-line excitation used $P_{21}+Q_1(14.5)/R_{12}+Q_2(20.5)/P_1(23.5)$ transition, for minimizing the other interferential effect. The measurements were taken NO concentration distribution in double swirling diffusion flame. In this swirl burner, NO concentration in downstream fo the flame decrease as primary/secondary air ratio increases.

• Journal of the Korean Society of Combustion
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• v.8 no.1
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• pp.25-35
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• 2003

The objective of this research is to determine generally applicable design principles for the development of internally staged combustion devices. Utilizing a triple annulus combustor, the detailed combustion characteristics are studied. For this triple air staged combustor, the angular momentum weighted by it#s swirl number and air distribution ratio was observed to be the critical criteria of NOx emission. An internal recirculation zone which develops on the centerline of the flame immediately downstream of the burner entraps the fuel into a fuel rich eddy. Then sufficient heat must be transferred from the flame via radiation to the chamber heat transfer surfaces, such that the peak flame temperatures are suppressed when the second air is introduced. It is experimentally found out that the total NOx emission level in this type of burner is below 50ppm(3% Ref. O2) at optimum operating conditions.

• Journal of ILASS-Korea
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• v.8 no.3
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• pp.33-40
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• 2003

The low-emission and high-performance diesel combustion is an important issue in the combustion research community, In order to understand the detailed diesel flame involving the complex physical processes, it is quite desirable to diesel spray dynamics, auto-ignition and spray flame propagation. Dynamics of fuel spray is a crucial element for air-fuel mixture formation, flame stabilization and pollutant formation, In the present study, the diesel RCM (Rapid Compression Machine) and the Electric Control injection system have been designed and developed to investigate the effects of injection pressure, injection timing, and intake air temperature on spray dynamics and diesel combustion processes, In terms of the macroscopic spray combustion characteristics, it is observed that the fuel jet atomization and the droplet breakup processes become much faster by increasing the injection pressure and the spray angle, With increasing the cylinder pressure, there is a tendency that the of spray pattern in the downstream region tends to be spherical due to the increase of air density and the corresponding drag force, Effects of intake temperature and injection pressure on auto-ignition is experimently analysed and discussed in detail.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.5
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• pp.343-348
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• 2009

The present study has experimentally investigated the effects of $CO_2$ diluted oxygen on the structure of swirl-stabilized flame in a lab-scale combustor. The methane fuel and oxidant mixture gas ($CO_2$ and $O_2$) were mixed in a pre-mixer and introduced to the combustor through different degrees of swirl vanes. The flame characteristics were examined for various amount of carbon dioxide addition to the methane fuel and various swirl strengths. The effects of carbon dioxide addition and swirl intensity on the combustion characteristics of pre-mixed methane flames were examined using chemiluminescence techniques to provide information about flow field. The results show that the hot combustion zone increases at the upstream reaction zone because of an increase in the recirculation flow for an increase in swirl intensity. The hot combustion zone is also increased at the downstream zone by recirculation flow because of an increase in swirl intensity which results in higher centrifugal force. The OH and CH radical intensities of reaction zone decrease with carbon dioxide addition because the carbon dioxide plays a role of diluted gas in the reaction zone.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.447-452
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• 2000

The low-emission and high-performance diesel combustion is an important issue in the combustion research community. In order to understand the detailed diesel flame field involving the complex Physical Processes, It Is quite desirable to study diesel spray dynamics, auto-ignition and spray flame propagation. Dynamics of fuel spray is a crucial element for air-fuel mixture formation flame stabilization and pollutant formation. In the present study, the diesel RCM (Rapid Compression Machine) and the Electric Control injection system have been designed and developed to investigate the effects of injection Pressure, injection timing, and intake air temperature on spray dynamics and diesel combustion processes. In terms of the macroscopic spray combustion characteristics it is observed that the fuel jet atomization and the droplet breakup processes become much faster by increasing the injection pressure and the spray angle. With increasing the cylinder pressure there is a tendency that the shape of spray pattern in the downstream region tends to be spherical due to the increase of air density and the corresponding drag force. Effects of intake temperature and injection pressure on auto-ignition is experimently analysed and discussed in detail.

• Korean Journal of Optics and Photonics
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• v.9 no.4
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• pp.264-269
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• 1998

The Measurement of concentration patterns for $C_2$, CH and OH radicals in the premixed propane-air flame could be managed through an image processing technique. This technique was applied to the three kinds of flames on a bunsen burner-mixtures of fuel to be lean, optimum and excessive respectively. The image processing system was complished by treating single wavelength flame images around the eac radical luminescence band, which was obtained by using a set of narrow band pass filters, an image intensifier, CCD and PC. It was possible to observe and predict the reaction zone and the concentration distribution of the radicals, Spatial distribution of each radicals in the raaction zone gave us enough informations to analyze the reaction mechanisms in $C_mH_n$ combustion process. According to this informations, the image of $C_2$ radical exists at front zone, following the images of CH and OH radicals at downstream.