• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.22-28
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• 2021

Combustion characteristics were examined experimentally for a swirl-stabilized double cone premixed burner nozzle used for industrial gas turbines for power generation. An original model and a variant with a different fuel injection pattern are tested to compare their combustion characteristics such as NOx, CO and stability in pressurized conditions with single burner-flame and in an ambient multi-flame conditions with multi-burners. Test results show that NOx emissions are smaller for the variant, whose number of fuel holes is reduced with the same total area of fuel holes, in ambient and pressurized single-flame conditions with single burner, which results from enhanced fuel/air mixing due to a higher penetration of fuel into the air stream. The multi-burnerflame test results show that NOx emissions are smaller for the variant due to reduced flame interactions, which, on the contrary, slightly reduces the stability margin. On-site test results fromin an actual power plants also show that NOx emissions are reduced for the variant, compared with the original one, which is in agreement with the lab test results stated above.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2349-2356
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• 2014

The recycling technology by the catalytic conversion is one of the most promising techniques for the $CO_2$ treatment of coal burning power plant flue gases. The conversion of $CO_2$ to valuable product of $CH_4$ can be used as a fuel to run the turbine for electricity generation. Through this technique, the amount of coal needed for the combustion in a gas turbine can be reduced as well as $CO_2$ emissions. Therefore, a series of catalysts based on cerium oxide doped with copper, nickel and manganese were prepared by impregnation method. From the characterization analysis, it showed that the prepared catalysts calcined at $400^{\circ}C$ were amorphous in structure with small particle size in the range below 100 nm. Meanwhile, the catalyst particles were aggregated and agglomerated with higher surface area of $286.70m^2g^{-1}$. By increasing the calcination temperature of catalysts to $1000^{\circ}C$, the particle sizes were getting bigger (> 100 nm) and having moderate crystallinity with lower surface area ($67.90m^2g^{-1}$). From the catalytic testing among all the prepared catalysts, Mn/Ce-75/$Al_2O_3$ calcined at $400^{\circ}C$ was assigned as the most potential catalyst which gave 49.05% and 56.79% $CO_2$ conversion at reaction temperature of $100^{\circ}C$ and $200^{\circ}C$, respectively.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.7
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• pp.79-88
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• 2006

In the present paper, the swirl flow structure and flame characteristics of turbulent premixed combustion in a model gas turbine combustor are investigated using large eddy simulation(LES). A G-equation flamelet model is employed to simulate the unsteady flame behavior. When inlet swirl number is increased, the distinct flow structures, such as the shapes of corner recirculation and center toroidal recirculation zone, are observed and the flame length is shorted gradually. Also, the phenomena of flashback are identified at strong swirl intensity. In order to get the accurate description of unsteady flame behavior, the predictive ability of the acoustic wave in a combustor is primarily evaluated. It is found that the vortex generated near the edge of step plays an important role in the flame fluctuation. Finally it is examined systematically that the flame and heat release fluctuation are coupled strongly to the vortex shedding generated by swirl flow and acoustic wave propagation from the analysis of flame-vortex interaction.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.4
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• pp.11-17
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• 2011

In order to see flame behavior in the annular reverse gas turbine combustor, sector combustion test was performed. Ignition test by using torch ignition system was carried out at various combustor inlet velocity and air fuel ratio. Also, flame blow out limit was measured by changing fuel flow rate with constant air mass flow rate. In test results, stable ignition is possible at air excess ratio of 6 and this limit is gradually increased with combustor inlet velocity. The minimum blow out limit is about 4 at 40 m/s of combustor inlet velocity. This blow out limit is also increased up to about 10 with increasing combustor inlet velocity. Test result shows that lean blow out limits are increased with air velocity. The highest blow out limit was found at the combustor inlet velocity of 65 m/s.

• Journal of Aerospace System Engineering
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• v.11 no.2
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• pp.9-15
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• 2017

In order to verify the possiblity of improving the combustion performance of ethanol using zeolite catalyst and the characteristics of nitrogen oxides and carbon monoxide emission, micro gas turbine experiments were performed using catalytic reaction products, ethanol and kerosene as fuels and the results were compared. The thrust of the catalytic reaction product was lower than that of kerosene, but it was improved by 5% on average compared with the use of ethanol. Nitrogen oxides and carbon monoxide emissions of the catalytic reaction products were measured to be very low overall compared to kerosene. As a result, when the ethanol was reformed using the zeolite catalyst, the engine performance could be improved while maintaining the environment friendliness of the ethanol.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.153-159
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• 2010

In order to see the flame behavior in the annular reverse gas turbine combustor, sector combustion test was performed. Ignition test by using torch ignition system was carried out at the various combustor inlet velocity and air fuel ratio. Also, flame blow out limit was measured by changing fuel flow rate with constant air mass flow rate. In the test results, stable ignition is possible at air excess ratio of 6 and this limit is gradually increased with combustor inlet velocity. The minimum blow out limit is about 4 at 40 m/s of combustor inlet velocity. This blow out limit is also increased up to about 10 with increasing combustor inlet velocity. Test result shows that lean blow out limits are increased with air velocity. The highest blow out limit was found at the combustor inlet velocity of 65m/s.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.5
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• pp.60-69
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• 2013

An optimum configuration of the hybrid/dual swirl jet combustor for a micro-gas turbine was investigated experimentally. Location of pilot nozzle, angle and direction of swirler vane were varied systematically as main parameters under the conditions of constant thermal load. The results showed that the variation in locations of inner fuel nozzle and pilot burner resulted in significant change in flame shape and swirl intensity due to the changes in recirculating flow pattern and minimum flow area near burner exit, in particular, with the significant reduction of CO emission near lean-flammability limit. In addition, it was observed that the co-swirl configuration produced less CO and NOx emissions compared to the counter-swirl configuration.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.5
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• pp.70-79
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• 2013

The isothermal flow structure and mixing characteristics of a hybrid/dual swirl jet combustor for micro-gas turbine (MGT) were numerically investigated. Location of pilot burner, swirl angle and direction were varied as main parameters with the identical thermal load. As a result, the variations in location of pilot nozzle, swirl angle and direction resulted in the significant change in turbulent flow field near burner exit, in particular, center toroidal recirculation zone (CTRZ) as well as turbulent intensity, and thus the flame stability and emission performance might be significantly changed. With the comparison of experimental results, the case of swirl angle $45^{\circ}$ and co-swirl flow including optimum location of pilot burner were chosen in terms of the flame stability and emissions for the development of hybrid/dual swirl jet combustor.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.75-76
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• 2014

The present study has numerically investigated the effects of the oxidizer-side nitrogen dilution on the precise structure and NOx formation characteristics of the turbulent syngas nonpremixed flames. Eulerian particle flamelet model was used to predicted the NOx formation characteristics in the turbulent syngas swirling nonpremixed flames. Current numerical simulation was conducted for the syngas gas turbine combustor. Numericla results indicate that as the H2O portion is increased in diluent, the formation of NOx decreased effectively in turbulent syngas swirl nonpremixed flames.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.492-497
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• 1998

Thermoacoustic oscillation is a significant problem in cylindrical-type combustors such as common internal combustion engines, industrial furnaces, gas turbine, etc. This kind of low frequency oscillation can give rise to serious troubles such as the destruction of system or producing of a strong noise. Accurate numerical simulation of thermoacoustic phenomena is a complex and challenging problem. Especially, considering the reaction of mixture intensifies the difficulty of analysis. Like as other simulations of the aerodynamics and aeroacoustics, direct computation of thermoacoustic phenomena requires that the Navier-Stokes equations be solved using accurate numerical differentiation and time-marching schemes, with non-reflecting boundary conditions. In this study,, numerical approach aims at qualitative analysis and efficient prediction of problem, not at the development of an accurate scheme. Overally speaking, numerical prediction is reasonably matched with experimental result.