• Journal of Advanced Marine Engineering and Technology
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• v.24 no.4
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• pp.421-426
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• 2000

A study on the combustion and exhaust emissions characteristics of diesel engine with various suction air humidity is performed experimentally. In this paper, suction air humidity is changed from RH 50% to RH 90%, the experiments are performed at engine speed 1800rpm, and main measured parameters are cylinder pressure, fuel consumption rate, CO, HC, NOx and Soot emissions etc. Increase of suction air humidity from RH 50% to RH 90% does not effect specific fuel consumption, decreases maximum pressure in cylinder, ratio of maximum pressure rise and net heat release, and delays ignition timing. Also, that increases CO and HC emissions, decreases NOx emissions, but does not constant in changing tendency on emission.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.3
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• pp.303-308
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• 2015

Compressed air has many uses on board ship, ranging from diesel engine starting to the cleaning of machinery during maintenance. In an effort to enhance the performance of the marine compressed air system, this work studied a way to reduce condensation from the air compressor via experiments. Especially more condensation is produced when the temperature at compressor outlets and the humidity of the air are higher. so in the research, drain production change has been observed by additionally installing the cooling fan on the suction portion of the air to air compressor and this is the method for reducing the compressed air drain that has passed through the compressor. For the result, it was verified that when the cooling fan was used, less drain was made where per hour it was 500.9ml of drain and the measured result after installing the cooling fan was that less drain was made. Other additional and various researches are needed including experiments like silica gel passing through the suction portion afterwards.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.6
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• pp.609-614
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• 2014

In this research, results of measuring temperature and relative humidity of underground-air-heat in Jeju showed $15{\sim}18^{\circ}C$ and 70~80% each which are somewhat high compare to other regions. So the Multi-effect dehumidifying and heating Heat Pump system which has merged functions of dehumidification and heating is made to solve this problem mentioned previously. When the suction air was $15^{\circ}C$ with 60% humidity, the outcome was 1.70 on $COP_h$ and 1.797(kg/h) on total amount of dehumidification, and also showed 1.87 $COP_h$ with 1.87 total amount of dehumidification under the condition of $20^{\circ}C$ and 80% humidity of suction air. Furthermore, $COP_h$ showed increased number which is 1.87 and also total amount of dehumidification increased which was 3.269(kg/h). The highest COP can be achieved at $17^{\circ}C$ and 70% relative humidity condition.

• Geomechanics and Engineering
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• v.37 no.2
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• pp.109-122
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• 2024

Standard triaxial cells are commonly used to measure the mechanical behavior of saturated soils. However, this type of standard system is difficult to use for unsaturated soil specimens since it cannot measure the changes in the pore-air volume and pressure. This paper proposes to extend the measurement possibilities of the standard triaxial testing device in a simple way and to adapt it to partially saturated soils. The system is supplied by two hygrometers installed at each end of the cylindrical unsaturated specimen to measure local relative humidity, which allows the derivation of suction. The volumetric strain of the specimen is calculated by analyzing digital photos captured from the outside of the transparent cell wall. Specimens made of kaolin clay, having different hydraulic properties, were tested to verify the reliability of the measurements, and thus, the relevance of the proposed techniques to study the mechanical behavior of unsaturated soils.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.3
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• pp.547-553
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• 1989

Last several stages of high capacity fossil power steam turbine and most stages of nuclear power steam turbine operate on wet steam. As a consequence, the flows in those cascades are accompanied by condensation, and the latent heat caused by condensation affects an oblique shock wave being generated at the vicinity of trailing of the blade. In the case of expanding of moist air through a suction type indraft wind tunnel, the effect of condensation affection the oblique shock wave generated by placing the small wedge into the supersonic part of the nozzle was investigated experimentally. In these connections, the relationship between condensation zone and reflection point of the incident oblique shock wave, angle between wedge bottom wall and oblique shock wave, and the variations of angles of incident and reflected shock waves due to the variation of initial stagnation relative humidity are discussed. Furthermore, the relationship between initial stagnation relative humidity and load working on the nozzle wall, obtained by measuring static pressure at the nozzle centerline, is discussed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.8
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• pp.2177-2183
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• 1994

The rapid expansion or condensible gas such as moist air of steam gives rise to nonequilibrium condensation. As a result of irreversibility of condensation process in the supersonic cascade flow of low pressure steam turbine, the entropy of the flow is increased, and the efficiency of the turbine is decreased. In the present study, to investigate the flow of moist air in 2-dimensional cascade made as the configuration of the tip section of the last actual steam turbine moving blade, the static pressure at both sides of pressure and suction of blade are measured by static pressure taps and the distribution of Mach number on both surfaces of the blade are obtained by using the measured static pressure. Also, the flow field is visualized by a schlieren system. From the experimental results, the effects of the stagnation temperature and specific humidity on the flow properties in a 2-dimensional stationary cascade of a practical steam turbine blade are clearly identified.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1658-1663
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• 2015

To control the indoor humidity, humidifier is installed in an air handling unit. Up to now, foreign product made of glasswool has been widely used as a humidifying element. In this study, a new humidifying element made of cellulose and PET was tested, and the performance was compared with Glasdek element, which is made of glasswool. Mass transfer rates and pressure drops were measured from the element which was installed at the entrance of the suction-type wind tunnel. Results show that, $j_m$ and f factors of the new element are 33%~39% larger and 0%~51% smaller than those of Glasdek. Large water absorption capacity and the smoothness of the new element appear to be responsible for the large $j_m$ and small f factor. The mass transfer effectivenesses ($j_m/f^{1/3}$) of the new element are 36%~63% larger than those of Glasdek.