• Journal of the Korean Society of Combustion
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• v.4 no.1
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• pp.85-93
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• 1999

Experimental study on a porous ceramic liquid fuel combustor is performed. Compact burner with low pollutant emission and high combustion efficiency is realized through the use of porous ceramic materials of high porosities. The use of porous ceramic materials in burner material results in rapid vaporization of liquid fuel and enhancement in mixing process, and thus nearly premixed combustion of liquid fuel is achieved instead of diffusion and partially premixed combustion method, which is often used and apt to produce high pollutant emissions such as CO, NOx and soot. With this enhanced vaporization and premixing method of liquid fuel vapor and air, it is found that enhanced combustion process with intense radiation output and better emission characteristics in NOx, CO and soot emission, compared to other conventional liquid fuel burning method, are possible.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.122-127
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• 2006

The objective of this research is to determine generally applicable design principles for the development of Rapid mix burner. Details operating RMB(Rapid mix burner) is designed that thermal NOx and prompt NOx formation be reduced through control of low peak flame temperature, and nearly uniform flame temperature by rapid mixing at the ignition point. Results from RMB(Rapid mix burner) achieving lower than 43 ppm NOx emissions and nearly flame temperature uniform

• 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 Mechanical Science and Technology
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• v.17 no.6
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• pp.906-913
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• 2003

Lean premixed combustion has been considered as one of the promising solutions for the reduction of NOx emissions from gas turbines. However, unstable combustion of lean premixed flow becomes a real challenge on the way to design a reliable, highly efficient dry low NOx gas turbine combustor. Contrary to a conventional diffusion type combustion system, characteristics of premixed combustion significantly depend on a premixing degree of combusting flow. Combustion behavior in terms of stability has been studied in a model gas turbine combustor burning natural gas and air. Incompleteness of premixing is identified as significant perturbation source for inducing unstable combustion. Application of a simple convection time lag theory can only predict instability modes but cannot determine whether instability occurs or not. Low frequency perturbations are observed at the onset of instability and believed to initiate the coupling between heat release rate and pressure fluctuations.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.279-282
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• 2002

Recently, gas turbines for power generation adopt multistage DLN(Dry Low NOx) type combustion, where diffusion combustion is applied at low load and, with increase in load, the combustion mode is changed to lean premixed combustion to reduce NOx emissive concentration. However, during the mode changeover from diffusion to premixed flame, unfavorable phenomena, such as flashback, high amplitude combustion oscillations, or thermal damage of combustor parts could frequently occur. In the present study, to apply for the analysis of such unfavorable phenomena, three-dimensional CFD investigations are carried out to compare the detailed flow characteristics and temperature distribution inside the gas turbine combustor before and after combustion mode changeover. The fuel considered here is pure methane gas. A standard $k-{\varepsilon}$ turbulence model with wall function and a P-N type radiation heat transfer model, have been utilized. To analyze the complex geometric effects of combustor parts on combustion characteristics, fuel nozzles, a swirl vane f3r fuel-air mixing, and cooling air holes on the combustor liner wall, are included in this simulation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.854-860
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• 2004

"Research and Development of Melt-Growth Composite (MGC) Ultra High Efficiency Gas Turbine System Technology" program has been started in JFY2001. The main objective of the program is to establish basic component technologies to apply MGC material to an efficient gas turbine system successfully. It is known that MGC material maintains its mechanical strength at room temperature up to about 2000 K, which is ideal for the high temperature gas turbine. The purposes of the present study are to develop the cooling structure of the gas turbine combustor liner where MGC material is applied as the heat shield panel, also to develop the low NOx combustion system for a 1970 K (1700 deg.C) class gas turbine combustor. To start with, basic heat transfer characteristics were investigated by one-dimensional calculation and heat transfer experiment for the cooling structure. Axially staged configuration and fuel preparation were investigated by CFD calculation and experiments for the low NOx combustor.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.449-452
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• 2004

“Flameless combustion” of lean to ultra lean mixtures, supported by high-temperature burned gas, can resolve the dilemma between complete combustion versus ultra-low NOx emissions in gas turbine combustors. The characteristics of NOx emissions and combustion in “lean-lean” two-stage combustion were investigated for fuel vapor and droplets / air mixture jets injected from the main injection tube that was placed perpendicular to the combustor wall into the primary hot burned gas prepared by combustion of lean mixtures on a perforated flame holder. The present results clearly show that the ultra-low NOx combustion supported by the reaction of lean mixtures well mixed with the hot burned gas from the primary stage is much more advantageous in achieving ultra-low NOx emissions while maintaining high combustion efficiency.

• 한국연소학회:학술대회논문집
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• 2001.11a
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• pp.153-160
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• 2001

The combustion test used DTF was performed to obtain the characteristics of NOx emission and reduction. In this test, major factor of NOx emission was a stoichiometric air ratio. At the onset of combustion to be rich oxygen, NOx was produced rapidly. Optimum condition for NOx reduction was formed under about AR:0.7 in the combustion test of Alaska coal. Investigations were undertaken with 200KW(th) test combustor. In combustion test, the major variables were coal feed ratio of center/outer, stoichiometric air ratio at the onset of combustion. The lowest NOx emission, 182ppm(6% O2 base), was achieved at about AR:0.6 of the first combustion stage with low NOx burner. Also, unburned carbon content of char collected in this combustion condition was about 1wt%.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.148-155
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• 2005

In this study, Development of 300,000kcal/hr high velocity Injection burner with fuel multi-stage was performed using experiments. The characteristics of NOx emission in multi fuel/air staged combustor have been experimentally studied. The design concept of multi fuel/air staged combustor is creation of two separate flame, a primary flame is largest access air combustion and the secondary flame is complete combustion zone, where most of fuel bums. Experiments were performed on an industrial scale in a laboratory furnace and Liquefied Natural Gas(LNG) was used as primary and secondary fuels. Comparison of outlet NOx and outlet Temperature under various air rate and primary/ secondary fuel ratio was performed. The test demonstrated that NOx emission con be reduced by 70% in accordance with operating conditions.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.7
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• pp.70-75
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• 2005

In this study, experimental investigations were conducted on NOx emission characteristics with fuel swirl flow in swirl combustor. Many types of vanes, which altered air and fuel swirl angles, were employed to verify the mixing processes. For strong air swirl, fuel counter-swirl resulted in relatively large turbulent intensity, high energy to the high frequency region and narrow width of high temperature region compared with co-swirl condition. These effects of fuel counter-swirl resulted in low NOx emission characteristics at strong air swirl condition. And NOx reduction mechanism was also discussed.