• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.2
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• pp.70-77
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• 2012

The selective catalytic reduction(SCR) system used to reduce NOx in diesel engines requires an NO/$NO_2$ ratio of about 1 in exhaust emissions to realize the fast SCR mode at temperatures lower than $300^{\circ}C$. This study investigated the characteristics of a plasma system as a pre-active apparatus for the fast SCR reaction mode of an SCR system. Plasma was generated by the pulse corona discharge(PCD) method with a four-channel wire-cylinder reactor. This study showed that plasma was easily generated in the exhaust gas by the PCD system, and the peak voltage of the normal state condition for plasma generation was generally 12 kV. The PCD system easily converted NO into $NO_2$ at lower temperatures and the NO/$NO_2$ conversion ratio increased with the discharge current for plasma generation. But the PCD system could not convert NO into $NO_2$ at higher engine speeds and higher engine loads due to the lack of oxygen in exhaust gas. The PCD system also activated the diesel oxidation catalysts(DOC) system to reduce CO emissions.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.10a
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• pp.195-200
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• 2004

In this study, a component map generation method using experimental data and the genetic algorithms are newly proposed. In order to generate the performance map for components of this engine, after obtaining engine performance data through many experimental tests, and then the third order equations which have relationships the mass flow function the pressure ratio and the isentropic efficiency as to the engine rotational speed were derived by using the genetic algorithms. A steady-state performance analysis was peformed with the generated maps of the compressor by the commercial gas turbine performance analysis program GASTURB(1). In comparison, it was found that the component maps can be generated from the experimental test data by using the genetic algorithms, and it was confirmed that the analysis results using the generated maps were very similar to those using the scaled maps from the GASTURB.

• Journal of ILASS-Korea
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• v.19 no.4
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• pp.204-210
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• 2014

Experimental study was conducted to investigate the effect of EGR(exhaust gas recirculation) on engine noise using single cylinder combustion ignition engine. Under constant engine rotary speed of 1200 RPM, 8 mg fuel quantity was injected with 15, 18 and 21% of oxygen ratio and 1400 bar of injection pressure. Using the in-cylinder pressure data acquired by a piezoelectric transducer, the engine performance parameters were calculated. Radiated engine noise measured for 10 seconds was analyzed using spectral characteristics and sound quality metrics such as loudness, sharpness, roughness. From the obtained engine performance parameters and sound quality metrics, effect of oxygen ratio of the premixed air, start of injection timing on frequency characteristic and sound quality metrics were analyzed. Correlation analysis was conducted between MPRR(maximum pressure rise rate), RI(ringing intensity) and sound quality metrics. RI was identified as the most important factor having influence on the sound quality metrics.

• International Journal of Aeronautical and Space Sciences
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• v.15 no.2
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• pp.123-137
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• 2014

The aviation gas turbine is composed of many expensive and highly precise parts and operated in high pressure and temperature gas. When breakdown or performance deterioration occurs due to the hostile environment and component degradation, it severely influences the aircraft operation. Recently to minimize this problem the third generation of predictive maintenance known as condition based maintenance has been developed. This method not only monitors the engine condition and diagnoses the engine faults but also gives proper maintenance advice. Therefore it can maximize the availability and minimize the maintenance cost. The advanced gas turbine health monitoring method is classified into model based diagnosis (such as observers, parity equations, parameter estimation and Gas Path Analysis (GPA)) and soft computing diagnosis (such as expert system, fuzzy logic, Neural Networks (NNs) and Genetic Algorithms (GA)). The overview shows an introduction, advantages, and disadvantages of each advanced engine health monitoring method. In addition, some practical gas turbine health monitoring application examples using the GPA methods and the artificial intelligent methods including fuzzy logic, NNs and GA developed by the author are presented.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.8
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• pp.996-1008
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• 1997

This paper describes a methodology and results for the analysis of a small steam injected gas turbine cogeneration system. A performance analysis program for the gas turbine engine is utilized with modifications required for the model of steam injection and the heat recovery steam generator (HRSG). The object of simulation is a simple cycle gas turbine engine under development which adopts a centrifugal compressor. The analysis is based on the off-design operation of the gas turbine and the compressor performance map is utilized. Analyses are carried out with the injection ratio as the main parameter. The effect of steam injection on the power and efficiency of gas turbine and cogeneration capacity is investigated. Also presented is the variation in the main operating parameters inside the HRSG. Remarkable reduction in NOx generation by steam injection is confirmed. In addition, it is observed that for the 100% power operation the temperature of the cooled first nozzle blade decreases by 100.deg. C at full steam injection, which seems to have a favorable effect on the engine life time.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.1
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• pp.114-120
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• 2016

This paper describes generating efficiency characteristics of the double acting Stirling engine/generator for domestic small-scale CHP (Combined Heat and Power) system. In small distributed generation applications, Stirling engine has competition from fuel cell, microturbine and etc. In order to be economical in the applications, a long life with minimum maintenance is generally required. Free piston Stirling engine (FPSE) has no crank and rotating parts to generate lateral forces and require lubrication. Double acting Stirling engine/generator has one displacer and two power piston which are supported by flexure springs. Two power pistons oscillate with symmetric displacement and are connected with moving magnet type linear generators for power generation from PV work. In experiments, 1 kW class double acting free piston Stirling engine/generator is fabricated and tested. Heat is supplied to hot end of engine by the combustion of natural gas and converted to electric power by linear generators which are assembled with power pistons. The electric parameters such as voltage, current and phase are measured with for variable flow rate of fuel gas. Especially, generating efficiency of FPSE is measured with three different measurement methods. Generating efficiency of the double acting Stirling engine/alternator is about 24%.

• Proceedings of the SAREK Conference
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• 2004.11a
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• pp.27-27
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• 2004

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.3
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• pp.96-101
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• 2005

Cogeneration is an energy conversion process, where electricity and useful heat are produced simultaneously in one process. Also, carbon dioxide emissions can be reduced as well. The cogeneration process may be based on the use of steam, gas turbines or combustion engines. However, there have been few models with an output of less than 100 kilowatt. In the present study, a spark ignited gas engine with generation output of 10 kilowatts was developed for micro cogeneration package. The gas engine shows 29.2$\%$ of thermal efficiency under Stoichiometric combustion and 33.6$\%$ of thermal efficiency under lean combustion. NOx emission shows less than 10ppm at 13$\%$ oxygen under stoichiometric combustion and about 100ppm at 13$\%$ oxygen under lean combustion.

• International Journal of Aeronautical and Space Sciences
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• v.10 no.2
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• pp.34-42
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• 2009

Gas turbine performance diagnostics is a method for detecting, isolating and quantifying faults in gas turbine gas path components. On-line precise fault diagnosis can promote greatly reliability and availability of gas turbine in real time operation. This work proposes a GUI-type on-line diagnostic program using SIMULINK and Fuzzy-Neuro algorithms for a helicopter turboshaft engine. During development of the diagnostic program, a look-up table type base performance module are used for reducing computer calculating time and a signal generation module for simulating real time performance data. This program is composed of the on-line condition monitoring program to monitor on-line measuring performance condition, the fuzzy inference system to isolate the faults from measuring data and the neural network to quantify the isolated faults. Evaluation of the proposed on-line diagnostic program is performed through application to the helicopter engine health monitoring.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.6
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• pp.642-648
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• 2017

The use of fossil is causing enviromental all over the world. So hydrogen energy is attracting attention as one of the alternative. The government announced that 30% of the air pollution is because of the Internal Combustion Engine Vehicle. In addition, they plans to reduce Internal Combustion Engine Vehicles by 2030 and increase (electric vehicles, EV) or (fuel cell vehicle, FCV). The FCV is evaluated as a next-generation green car because it has a long driving distance and short charging time. However, the hydrogen industry is not able to expand due to the lack of refueling infrastrucutre. This paper predicts the site of hydrogen refueling stations for the expansion of the hydrogen industry and proposes a method to supply hydrogen multi energy filling stations.