• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.340-344
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• 2008

The importance of the more efficient cogeneration system is emphasized. Also the more clean energy is needed at recent energy system. The cogeneration system using Lean burn engine is more preferred to the system using Rich burn engine because of the electrical efficiency. Although the cogeneration system using Lean burn engine is economically preferred, because of the NOx emission level, the system using Rich burn engine with 3-way catalyst can only be used in Korea. The NOx regulation level is 50ppm at oxygen level 13%. The cogeneration hybrid system using Lean burn engine is up to be optimized because of the large amount of the extra-fuel at the after-burner system. The after-burner system at different concept was applied. The reduction time for the activation temperature of the DeNOx catalyst was achieved by making a hole between the combustor and boiler. Because of the lowered fuel consumption, the lowered temperature level was optimized by blocking the hole of the boiler The optimized cogeneration hybrid system consumes $76Nm^3/h$ LNG to produce 150kW electricity compared to before optimization $103Nm^3/h$ LNG. The system was accurately evaluated and the result is following ; 90% total efficiency, below 10 ppm NOx, 50ppm CO, 25ppm HC. The cogeneration hybrid system can meet the current NOx level and exhaust gas regulation. It can achieve the clean combustion gas and efficient cogeneration system.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.136-140
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• 2013

The stringent emission norms cannot be met through engine design and exhaust after treatment alone. Use of oxygenated fuel like biodiesel as a alternative to diesel may be the best way to reduce emissions today. In this study, Diesel fuel and pure biodiesel (mahua oil) were tested on a single cylinder naturally-aspirated direct-injection diesel engine. The study aims to investigate the effects of the mahua oil biodiesel on existing diesel engine emissions. The effect of test fuels on engine emissions like CO, HC, $CO_2$, NOx and smoke emissions was investigated with respect to the load on engine. Smoke opacity of Diesel engine was lower in case of biodiesel of mahua oil as compare to mineral diesel. NOx emissions was little higher during the whole range of loading, which is a typical characteristic of biodiesel. However the increments are within in the narrow range. $CO_2$ emissions was bit higher which is the indication of better combustion due to presence of rich oxygen in the mixture, it results in the low values of CO and HC during the whole range of experiments. Thus considering environmental norms most of the engine emissions, it can be concluded and biodiesel derived from mahua oil could be used in a conventional diesel engine without any modification.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.4
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• pp.44-51
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• 2017

An experimental results on the dynamic characteristics of hydrocarbon/air premixed flames with ultrasonic standing waves are presented and compared. Images of the propagating flames were acquired by using a high-speed camera, and the flame behavior of methane/air and propane/air premixed flame were closely scrutinized through the image post-processing. At the fuel-lean conditions, the flame propagation velocity increased due to the intervention of the ultrasonic standing wave and vice versa at the fuel-rich conditions.

• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.201-208
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• 2003

Wheat dust cloud를 $5{\times}5{\times}214.1cm^3$ square tube내부에 발생시켜 화염의 전달과 연소 한계에 관한 연구를 수행하였다. 사용된 미립자는 $160{\mu}m-300{\mu}m$의 크기로 분류되어 주로 사용되었고 $300{\mu}m-325{\mu}m$크기의 미립자가 더불어 사용되었다. 연소 튜브는 연료로 사용되는 미립자를 튜브의 상단에서부터 컨베이어 벨트를 사용해서 공급받아 튜브의 하단에서 전기코일을 사용하여 점화시키는 구조로 고안되었다. 화염의 최대 진행속도는 작은 크기와 보다 큰 크기의 미립자를 사용했을 때가 각각 523cm/sec와 373cm/sec로 측정되었다. 연소 속도는 입자의 크기와 집접도(concentration)에 따라 변화를 보였는데 최소 3cm/sec에서 최대 7.5cm/sec로 관측되었다. 그러나 화염의 두께는 놀랍게도 입자의 집접도와 큰 연관이 없어 보였는데, 이는 앞으로도 보다 많은 연구를 통한 검증이 필요하리라 생각된다. 끝으로 fuel rich flammability는 $790g/m^3$으로 stoichiometric mixture $230g/m^3$에 비교해 월등히 높은 값으로 관측되었다.

• 한국연소학회:학술대회논문집
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• 2002.11a
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• pp.11-17
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• 2002

The first-order conditional moment closure (CMC) model is applied to $CH_4$/Air turbulent jet diffusion flames(Sandia Flame D, E and F). The flow and mixing fields are calculated by fast chemistry assumption and a beta function pdf for mixture fraction. Reacting scalar fields are calculated by elliptic CMC formulation. The results for Flame D show reasonable agreement with the measured conditional mean temperature and mass fractions of major species, although with discrepancy on the fuel rich side. The discrepancy tends to increase as the level of local extinction increases. Second-order CMC may be needed for better prediction of these near-extinction flames.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.10
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• pp.1038-1047
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• 2009

The development process of a gas generator for a 30-tonf pump-fed space liquid rocket engine is described. Starting from the development of an injector, followed by subscale and full-scale test specimens, the development of LOx/kerosene fuel-rich gas generator has been concluded successfully. Various analytical methods have been utilized in the course of design and the performance requirements have been verified experimentally through ignition tests, combustion performance and stability assessment tests and duration tests. The gas generator has proven its workability and stability within a defined operation window of varying chamber pressure and mixture ratio and demonstrated compliance to the performance and life time requirements.

• 한국연소학회:학술대회논문집
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• 1997.06a
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• pp.61-68
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• 1997

The morphology and size distribution of chromium oxides and the concentration measurement of atomic arsenic have been studied in laminar diffusion flames. Nitrogen was added to vary flame temperatures in hydrogen flames. Ethene flames were used in order to investigate the potential for interaction between the soot aerosol that is formed in these flames and the chromium aerosol. Two sources of chromium compounds were introduced: chromium nitrate and chromium hexacarbonyl. A detailed investigation of the morphology was carried out by scanning electron microscopy (SEM). The amounts of Cr(VI) and total Cr were determined by a spectrophotometric method and by X-ray fluorescence spectrometry, respectively. Also, LIF was used for the measurement of atomic arsenic, which was excited at 197.2 nm and was detected at 249.6 nm. Results showed that the morphology of the particles varied with the flame temperature and with the chromium source. The particles were characterized by porous structures, cenospheres and agglomerated dense particles when chromium nitrate solution was added to the flames. At low to moderate temperatures, porous sintered cenospheric structures were formed, in some cases with a blow hole. At higher temperatures, an agglomerated cluster which was composed of loosely sintered submicron particles was observed. It was also found that the emission of Cr(VI) from the undiluted $H_2$ flame was more than 10 times larger than in the 50% $H_2$ / 50% $N_2$ flame on a mass basis. Single point LIF measurement of atomic arsenic indicated that arsenic exist only in the low temperature, fuel rich region.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.4
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• pp.337-343
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• 2009

Noncatalytic partial oxidation of methane for producing synthesis gas was studied in a lab-scale experimental apparatus. Partial oxidation developed for high-temperature, fuel-rich combustion and it is exothermic process. but Steam reforming and Caron reforming is highly endothermic process to need much energy. Noncatalytic partial oxidation of methane is affected by temperature and equivalent ratio, so we studied effect about composition of synthesis gas at lab scale reactor. We used electronic heater to control the temperature of reactor. The quality of synthesis gas is improved and reduced heat value to require at Noncatalytic partial oxidation because the reacting temperature is lower at oxy condition.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_3
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• pp.1247-1260
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• 2022

The steel industry accounts for about 5% of the total annual global energy consumption and more than 6% of the total anthropogenic carbon dioxide emissions. Therefore, there is a need to increase energy efficiency and reduce greenhouse gas emissions in these industries. The utilization of coke oven gas, a byproduct of the coke plant, is one of the main ways to achieve this goal. Coke oven gas used as a fuel in many steelmaking process is a hydrogen-rich gas with high energy potential, but it is commonly used as a heat source and is even released directly into the air after combustion reactions. In order to solve such resource waste and energy inefficiency, several alternatives have recently been proposed, such as separating and refining hydrogen directly from coke oven gas or converting it to syngas. Therefore, in this study, recent research trends on the separation and purification of hydrogen from coke oven gas and the production of syngas were introduced.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1068-1071
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• 2017

The turbine exhaust system consists of a turbine flange, heat exchanger, exhaust duct and thrust nozzle. Heat exchanger is used for the launch vehicle because of the advantage of reducing the weight of the helium gas and the storage tank by using the heat exchanger pressurization method compared to the cold gas pressurizing method. Since the gas generator is combusted in fuel-rich condition, the soot is contained in the combustion gas. Hence, the heat exchanger should be designed considering the reduction of the heat exchange efficiency due to the soot effect. In addition, the uncertainty of the heat exchange calculation and the evaluation of the influence of the combustion gas soot on the heat exchange can not be completely calculated, so the design requirements must include a structure that can guarantee and control the temperature of the heat exchanger outlet. In this paper, it is described that the component allocation, the design method considering the manufacture of internal structure, the advantages of new concept of nozzle design.