• Journal of Mechanical Science and Technology
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• v.18 no.9
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• pp.1640-1647
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• 2004

This study was to investigate the effects of water induction through the air intake system on the characteristics of combustion and exhaust emissions in an IDI diesel engine. The fuel injection timing was also controlled to investigate a method for the simultaneous reduction of smoke and NOx when water was injected into the combustion chamber. The formation of NOx was significantly suppressed by decreasing the gas peak temperature during the initial combustion process because the water played a role as a heat sink during evaporating in the combustion chamber, while the smoke was slightly increased with increased water amount. Also, NOx emission was significantly decreased with increase in water amount. A simultaneous reduction in smoke and NOx emissions was obtained when water was injected into the combustion chamber by retarding more 2$^{\circ}C$A of the fuel injection timing than without water injection.

• The KSFM Journal of Fluid Machinery
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• v.8 no.5 s.32
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• pp.22-28
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• 2005

As the water supply facilities are recently getting larger, the domestic waterworks become multi-regional water supply system. Large water supply facilities generally consist of the intake pumping station, water treatment plant and water supply/distribution facilities. Although the pumping stations and the pipeline systems are used to pump up water, it often happens pipeline damage and flooding accident by the water hammer. In this paper, the intake pumping station is guaranteed by both the computer simulation and the field test analysis. This study is contributed to the safe operation program for the pumping station in which results of the adjustment on the safety plan of the pumping station, the air valve and the valve closing time.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.4
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• pp.72-79
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• 1994

In an automotive spark ignition, it is important to form the proper mixture(air/fuel) on each driving condition for developing the stabilizing combustion and exhaust characteristics. Since most of supply fuel is attached on the inside wall of the intake manifold for unadequate atomization by fuel injection system, it brings a bad effect on combustion and exhaust caused by nonuniformity of fuel distribution to each cylinder and mixture variation. Also it affects engine performance variation and causes noises and vibration. In this study, we verified the effect of the mixture variation which is caused by fuel liquid film in an intake manifold on combustion characteristics and engine performance.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.3
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• pp.97-108
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• 2018

It is definitely important to measure thrust during ground test when developing air-breathing engine, and in case of air-breathing engine, gross thrust should be calculated considering not only the measured thrust but also the force induced by the air flow of engine intake. Also, side thrust like yaw and pitch should be measured and analyzed using multi-component thrust measurement system. Engine performance was accurately evaluated by calculating the gross thrust of air breathing engine precisely which is analyzed from below serial procedure: labyrinth seal isolation, 1-axis gross thrust calculation, develop multi-component thrust measurement system, and side thrust analysis.

• Journal of the Korean Society of Mechanical Technology
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• v.20 no.6
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• pp.917-923
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• 2018

The drinking water supply system applicable to the laying hen consists of air-water heat pumps, drinking water tanks, heat stroage tank, circulation pumps, PE pipes, nipples, and control panels. When the heat pump system has power of 7.7 to 8.7 kW per hour, the performance coefficient is between 3.1 and 3.5. The supply temperature from the heat pump to the heat stroage tank was stabilized at about $12{\pm}1^{\circ}C$, but the return temperature showed a variation of from 8 to $14^{\circ}C$. Stratified temperature in the storage tank appeared at $12.^{\circ}C$, $13.5^{\circ}C$ and $14.4^{\circ}C$, respectively. The drinking water supply temperature remained set at $15^{\circ}C$ and $25^{\circ}C$, and the conventional tap water showed a variation for $23^{\circ}C$ to $30^{\circ}C$. As chickens grow older, the amount of food intake and drinking water increased. $y=-0.0563x^2+4.7383x+8.743$, $R^2=0.98$ and the feed intake showed $y=-0.1013x^2+8.5611x$. In the future, further studies will need to figure out the cooling effect on heat stress of livestock.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.2
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• pp.18-24
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• 1999

Liquid ramjet combustor is closely connected with complex phenomena due to a series of processes such as intake air, spray, mixing, and combustion. The present numerical experiments were peformed to investigate these flow characteristics for two and three dimensional liquid ramjet combustor. Grid system was made with three domains: intake region where air is supplied and fuel is injected, combustor and nozzle region, and exit atmosphere region. The numerical results showed that two and three dimensional flow patterns in recirculation region of combustor were significantly different each other and spray model was necessary to predict correctly the chemical reaction flow characteristics. Numerically examined for two different location of fuel injector, one is located on the bottom position of curved intake and the other is located on the top position. We found that bottom position of fuel injector is better than top position because fuel influx to the recirculation region which is need to sustain chemical reaction is more than the latter.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.1
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• pp.42-49
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• 2006

In this research. the diesel cycle was thermodynamically interpreted to evaluate the possibility of high efficiency by converting diesel engines to the high expansion diesel cycle, and general cycle features were analyzed after comparing these two cycles. Based on these analyses. an experimental single cylinder a long stroke with high expansion-diesel engine. of which S/B ratio was more than 3, was manufactured. After evaluating the base engine through basic experiments, a diesel engine was converted into the high expansion diesel engine by establish VCR device and VVT system Accordingly, the high expansion diesel cycle can be implemented when the quantity of intake air is compensated by supercharge and the effective compression ratio is maintained at its initial level through the reduction of the clearance volume. In this case, heat efficiency increased by $5.0\%$ at the same expansion-compression ratio when the apparent compression ratio was 20 and the fuel cut off ratio was 2. As explained above, when the atkinson cycle was used for diesel cycle, heat efficiency was improved. In order to realize high expansion through retarding the intake value closing time, the engine needs to be equipped with variable valve timing equipment, variable compression ratio equipment and supercharged pressure equipment. Then a high expansion diesel cycle engine is realized.

• The KSFM Journal of Fluid Machinery
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• v.12 no.3
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• pp.13-18
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• 2009

This paper describes flow characteristics in a piping system having various duct shapes on refuse collecting system. A simulator for the refuse collecting system is designed to analyze the flow characteristics in the piping system. The simulator consists of an air intake, a waste chute, circular duct having various shapes, cyclone and turbo blower. The simulator has four different duct shapes: straight, curved, inclined and Y-shaped ducts. Three-dimensional Navier-Stokes analysis is introduced to analyze the pressure loss in the piping system. Throughout the numerical simulation, pressure loss obtained by numerical simulation has a good agreement with the results of experimental measurements. The selected length of curved and Y-ducts for the pressure loss is determined using pressure distributions on the duct. Flow and pressure characteristics in the piping system of the simulator are evaluated by numerical simulation and discussed in detail.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.1
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• pp.35-44
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• 2016

Leading national R&D project to design a PWR spent nuclear fuel interim dry storage system that has been under development since mid-2009, which consists of a dual purpose metal cask and concrete storage cask. To ensure the safe operation of dry storage systems in foreign countries, major confinement monitoring techniques currently consist of pressure and temperature measurement. In the case of a dual purpose metal cask, a pressure sensor is installed in the interspace of bolted double lid(primary and secondary lid) in order to measure pressure. A concrete storage cask is a canister based system made of double/redundant welded lid to ensure confinement integrity. For this reason, confinement monitoring method is real time temperature measurement by thermocouple placed in the air flow(air intake and exit) of the concrete structure(over pack and module). The use of various monitoring technologies and operating experiences for the interim dry storage system over the last decades in foreign countries were analyzed. On the basis of the analysis above, development of the confinement monitoring technology that can be used optimally in our system will be available in the near future.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.77-84
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• 2002

For the purpose of obtaining a fundamental data which is needed to develope the port injection type charged LPLi engine system, we manufactured intake port injection system of liquid charging LPG and modified heavy duty single cylinder LPLi engine from heavy duty diesel engine. Engine output and emission characteristics were analyzed under variable air/fuel ratio and charging pressure. Since LPG is consisted of propane and butane, we investigated combustion characteristics using this two kinds of fuel. From the result of charging engine performance test, engine torque increase about 30% ∼ 40% with 0.3bar charging pressure. In low speed condition, as charging pressure increase, combustion stability improve ill lean bum condition, but, in high speed condition, combustion stability make worse in lean bum condition. We know that engine output decreased rapidly from the condition of air excess ratio 1.3. In addition, we measured emission characteristics under the lean bum and charging condition. From this experiment, we found that CO emission is out of the question in the range from stiochiometric to lean burn and charging condition, but charging pressure has influence on HC emission.