• Corrosion Science and Technology
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• 제9권6호
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• pp.331-337
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• 2010

This study compared the macro and micro electrochemical characteristics at the local area of welding metal on dissimilar welding parts for type 304 stainless steel (SS) and type 316L SS. The materials are used for double wall gas pipe of duel fuel engine for a ship. The various potentiodynamic experiments were performed several times in 10% ${H_2C_2O_2}{\cdot}{H_2O}$ solution using macro and micro methods, respectively. The micro electrochemical experiments conducted to resolve at local area on cross-section of dissimilar welding materials by micro-droplet cell device. The micro-droplet cell techniques can be used almost electrochemical experiments to resolve corrosion characteristics of the limited electrode area of the metallic surface between wetted spot of working electrode and tip of sharpened capillary tube. The results of macro electrochemical experiments show that resistance of active dissolution reaction at welding zone was high due to low current density by formation of passivation protection film at passive region. According to the micro electrochemical experiment, the corrosion current density of welding zone and bond zone were relatively high.

• Advances in Energy Research
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• 제3권3호
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• pp.181-194
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• 2015

In this work, an experimental study of the gasification on wood was carried out in downdraft type fixed bed Gasifier attached with 10 kW duel fuel diesel engine. The main objective of the study was to use wood as the biomass fuel for downdraft Gasifier and to evaluate the operating parameter of gasifier unit to predict its performance in terms of gas yield and cold gas efficiency. The influence of different biomass on fuel consumption rate, gas yield and cold gas efficiency was studied. Composition of producer gas was also detected for measuring the lower heating value of producer gas to select the feed stock so that optimum performance in the existing gasifier unit can be achieved. Under the experimental conditions, Lower heating value, of producer gas, cold gas efficiency and gas yields, using wood as a feed stock, are $4.85MJ/m^3$, 46.57% and $0.519m^3/kg$.

• 한국자동차공학회논문집
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• 제7권7호
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• pp.24-31
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• 1999

The MPI engine becomes increasingly popular because it meets two requirements of stringent pollutant emission and the lower fuel consumption. Even though supplies the same amount of fuel to each cylinder , it is hard to precisely control the air-duel ration due to the different amount of air flowing into each cylinder. The uniformity of air-fuel ration in each cylinder is considerably affected by the plenum chamber configuration . This study is focused on experimentally analyzing the flow characteristics within the plenum chamber In the present experiment , steady and valve dynamic state flow tests are performed and the flow field inside the plenum chamber is visualized and measured by utilizing a laser sheet visualization technique and a PTV method. These measured results indicate that the flow structure in the plenum chamber is highly influenced by the plenum chamber configurations, suction flow rates, crank speeds and so on.

• 한국분무공학회지
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• 제8권2호
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• pp.1-6
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• 2003

The liquid phase LPG injection (LPLI) system (the third generation technology) has been considered as one of the next generation fuel supply systems for LPG vehicles, since it has a very strong potential to accomplish the higher power, higher efficiency, and lower emission characteristics than the mixer type(the second generation technology) fuel supply system However. when a liquid LPG fuel is injected into the inlet duct of an engine, a large quantity of heat is extracted due to evaporation of fuel. This leads to freezing of the moisture in the air around the outlet of a nozzle, which is called icing phenomenon. It may cause damage to the outlet nozzle of an injector or inlet valve seat. In this work, the experimental investigation of the icing phenomenon was carried out The results showed that the icing phenomenon and process were mainly affected by humidity of inlet air instead of air temperature in the inlet duel. Also, it was observed that the total ice formed around the nozzle weighs at about $150mg{\sim}260mg$ after injection for ten minutes. And some fuel species were found in the ice attached at the front side of a nozzle, while frozen ice attached at the back of a nozzle was mostly' consisted of moisture of inlet air. Therefore, some frozen ice deposit. detached from front nozzle of an injector, may cause a problem of unfavorable air fuel ratio control in the small LPLI engine.

• 한국분무공학회지
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• 제14권1호
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• pp.34-38
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• 2009

This paper presents the pulsation of carburetor inlet and outlet pressure of a small SI gasoline engine. The engine used in this paper is a 23cc, single cylinder, diaphragm carburetor, two-stroke, air-cooled for brush cutter. The rpm and pressure wave pulsation at the inlet and the outlet of carburetor were measured and analysed for the understand of the internal air flow into the barrel on the diaphragm carburetor. These data should be used for the development of the duel fuel injection system for gasoline and LPG. The results showed that the carburetor inlet pressure variations were very steady, but the pressure variations at carburetor outlet were very sensitive to the pressure variation into the crank case and were to similar independently to the engine speed on partial opened throttle conditions. According to increasing engine speed, the pressure waves started to come out and be developed after closing the intake port of the engine at carburetor outlet. Reverse flow occurred on the WOT (wide open throttle) condition.

• Journal of Advanced Marine Engineering and Technology
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• 제35권1호
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• pp.68-74
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• 2011

본 논문은 LNG 선박의 이중연료엔진의 이중벽 가스파이프의 재료인 STS 304와 STS 316L에 대하여 GTAW에 의해 용접된 동종 및 이종 용접부의 기계적 특성과 용접성을 평가하였다. STS 304 동종 용접부의 경우, STS 316L 동종 용접부에 비해 모재 대비 현저하게 기계적 특성이 감소하는 경향을 나타냈다. 미세조직 관찰 결과, STS 304 동종 용접부가 STS 316L 동종 용접부에 비해 침상 페라이트가 많이 형성되어 상대적으로 높은 경도를 나타냈다.