• Journal of Advanced Marine Engineering and Technology
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• v.23 no.4
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• pp.543-551
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• 1999

Diesel engine is a major source of the air pollution. In general the concentrations of these pollu-tants in diesel engine exhaust differ from values calculated assuming chemical equibrium. Thus the detailed chemical mechanisms by which these pollutions form and the kinetic of these process-es are important in determining emission levels. In this study the computer program has been developed to calculate the required thermodynam-ic properties of combustion products(10 spacies) for both equilibrium and non-equilibrium in cylin-der for diesel engines. Nitric oxide emissions are calculated by using the extended Zeldovich Kinet-ic mechanism with a steady state assumption for the N concentration and equilibrium values used for H, O, $O_2$ and OH concentrations. By the results it is confirmed that developed simulations program with the NO prediction model is validated against residual mass fraction combustion index of Wiebe's functions pre-mixed com-bustion ration fuel injection timing.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.41-43
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• 2013

In order to simulate and visually observe combustion phenomena in cylindrical radial-flow porous inert media, a radial multi-channel burner, made of transparent quartz plates, was fabricated. Flame stabilization characteristics and its pulsating instability in the burner were experimentally investigated with respect to various mixture flow rates and equivalence ratio. As a result, five different flame behaviors, such as stable flame, pulsating instability, sudden extinction, blowout and unstable extinction, were observed. Mean radial position of circularly arranged multi-flame and its averaged burning velocity were measured and then compared to the freely propagating flame. The multi-flame pulsation frequency is about several tens of Hz and it is supposed to be generated by the heat diffusion enhancement to cold pre-mixture by the intensive gas-solid interaction.

• Clean Technology
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• v.19 no.4
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• pp.437-445
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• 2013

To develop SEWGS (sorption enhanced water gas shift) system using dry $CO_2$ absorbent for pre-combustion $CO_2$ capture, hydrodynamic characteristics of $CO_2$ absorbents were measured and investigated. The minimum fluidization velocity of $CO_2$ absorbent was measured and the effects of the operating conditions were investigated to operate the system at bubbling fluidized bed condition. The minimum fluidization velocity decreased as pressure and temperature increased. Moreover, the minimum fluidization velocity decreased as column diameter increased. The effects of operating conditions on the solid circulation rate were measured and investigated to select appropriate operating conditions for continuous $CO_2$ capture and regeneration. The measured solid circulation rates were ranged between 10 and 65 kg/h and increased as the solid injection velocity, gas velocity in the regeneration reactor, and solid height increased.

• Journal of the Korean Society of Safety
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• v.5 no.1
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• pp.7-18
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• 1990

This study measured the smouldering temperature of dust layer for various combustible natural polymer material by practical apparatus. The dust layer was either put on the preheated plate of constant temperature, or formed with cylinderical metal sleeve of various diameters and depths at room temperature and then heated up to a pre-determined smouldering temperature. Plots of arrival times versus smouldering temperature were made to compare the smouldering characteristics with kinds of dusts. The natural polymer material was divided into theree groups by characteristics of smouldering mechanism. This groups are cellulose group, lipide group and glucose group.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.99-102
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• 2002

The BSCCO superconductor materials of using Self-propagating High-temperature Synthesis (SHS) were studied. Mechano-chemical activation - as a pre-treatment of the reactants mixture - strongly influences the kinetic parameters, the reaction mechanism, and the composition and structure of the final product. In this paper as an effort for fabricating the SHSed BSCCO superconductor powder SHS method was considered to application in the synthesis of superconducting materials.

• Journal of Korea Ship Safrty Technology Authority
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• s.23
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• pp.37-50
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• 2007

The test result is a part of a study on the reduction of fuel expense. the test was conducted in the ship of east sea fisheries supervision office which is modified from 139 ton trawler to 183 ton petrol ship. The result of NOx emission and Smoke Value for main engine and generator engine are measure and included in this paper. The information on pre-treatment systems and measuring equipment also includes.

• Journal of Energy Engineering
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• v.4 no.1
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• pp.85-94
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• 1995

본 연구에서는 최근 차량용 대체연료로서 주목받고 있는 천연가스의 연소특성을 규명하기 위해 밀폐된 정적연소실을 이용, 당량비, 초기압력 및 점화위치 변화에 따른 연소실험을 행하였으며, 그 결과 다음과 같은 결론을 얻었다. 메탄-공기 예혼합기의 화염전파과정은 이론혼합기 부근에서 구면형으로 진행되는데 반해, 과농 또는 과박 혼합기 그리고 점화위치가 연소실 벽면에 가까울수록 타원형으로 진행되며, 초기압력이 증가함에 따라 화염전파는 느려진다. 화염전파속도와 연소 속도는 초기압력이 낮고 점화위치가 연소실 중심에 가까울수록 빠르며, 당량비 1.0∼1.1 사이에서 최대치를 보인다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.3 no.1
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• pp.1-9
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• 1979

Methanol was examined as supplemental fuel for open chamber type and pre-combustion chamber type diesel engine. Pre-determined quantities of diesel oil were injected as ordinary diesel engines and methanol was added at inlet pipe using venturi, nozzel and and float chamber for the rest of the charge. In this mode of operation, addition of methanol reduced inlet and exhaust temperature. Inlet air quantities were essentially unchanged in spite of lower inlet temperature. Exhaust smoke was significantly reduced At light load when both diesel oil and methanol were introduced with small quantities, specific heat consumption was considerably increased. However, with the increase of the quantity of methanol or diesel oil, specific heat consumption was improved. With sufficient quantities of diesel oil enough to produce the power above 3/4 load, addition of methanol showed better thermal economy.

• Journal of the Korean Institute of Gas
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• v.17 no.1
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• pp.7-12
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• 2013

As emission regulation for vehicle has been reinforced, many researches carried out for HCNG(hydrogen-natural gas blends) fuel to the conventional compressed natural gas (CNG) engine. However, abnormal combustion such as backfire, pre-ignition or knocking can be caused due to high combustion speed of hydrogen and it can result in over heating of engine or reduction of thermal efficiency and power output. In the present study, improvement of combustion performance was observed with HCNG fuel since it can extend a flammability limit. Knocking characteristics for CNG and HCNG fuel were investigated. Feasibility of HCNG fuel was evaluated by checking the knock margin according to excess air ratio. The operation of engine with HCNG was stable at minimum advance for best torque(MBT) spark timing and knock phenomena were not detected. However, it is necessary to prepare higher knock tendency since possibility of knock is higher with HCNG fuel.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.449-456
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• 2010

The HCCI engine is a prospective internal combustion engine with which high diesel-like efficiencies and very low NOx and particulate emissions can be achieved. However, several technical issues must be resolved before HCCI engines can be used for different applications. One of the issues concerning the HCCI engine is that the operating range of this engine is limited by the rapid pressure rise caused by the release of excessive heat. This heat release is because of the self-accelerated combustion reaction occurring in the engine and the resulting engine knock in the high-load region. The purpose of this study is to evaluate the role of thermal stratification and fuel stratification in reducing the pressure rise rate in an HCCI engine. The concentrations of NOx and CO in the exhaust gas are also evaluated to confirm combustion completeness and NOx emission. The computation is carried out with the help of a multizone code, by using the information on the detailed chemical kinetics and the effect of thermal and fuel stratification on the onset of ignition and rate of combustion. The engine is fueled with dimethyl ether (DME), which allows heat release to occur in two stages, as opposed to methane, which allows for heat release in a single stage.