• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.840-843
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• 2003

The Paper presents theoretical and experimental investigation of plunger type water hydraulic pump (plunger pump). An analysis of Crank shaft for plunger pump is carried out. With this results, the optimal dimensions of plunger pump are determined. And performance test results about slide resistance, hydraulic leak test, efficiency-pressure. and flow-speed and flow-pressure are presented.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.4
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• pp.418-424
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• 2004

An abrupt high pollution loads in combined sewer systems is believed to be caused by first flushing actions and the resuspension of sediments deposited in sewers. Therefore, pollution loads in each flow regulator have a different tendency. This systems control intercepting flow in each flow regulator using water quality and water level. A desired quantity of intercepting flow was adjusted and the necessary slide position for a constant intercepting is calculated by Optimization programming. This systems make it possible to reduce pollution loads caused by CSOs to water body, may be alternative for the stable operation of STP through improving water quality to STP.

• Korea-Australia Rheology Journal
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• v.18 no.4
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• pp.209-215
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• 2006

Recent research results on viscocapillary models of various pre-metered coating flows such as curtain, slide, and slot coatings have been reviewed in this paper. Such one-dimensional models have been simplified from two-dimensional Navier-Stokes equations for viscous coating flows with free surfaces, using integral momentum balances and lubrication approximation. It has been found that these viscocapillary models is capable of predicting flow dynamics in various coating systems, providing the good agreement with results by 2-D models.

• Journal of the Korean Society of Visualization
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• v.1 no.1
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• pp.75-81
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• 2003

A custom micro-PIV optics assembly has been used to measure the flow fold inside a T-junction of a microchannel. The micro-PIV system consists of microscope objectives of various magnifications, a dichroic cube, and an 8-bit CCD camera. Fluorescent particles of diameters 620 nm have been used with a Nd:YAG laser and color filters. A programmable syringe pump with Teflon tubings were used to inject particle-seeded distilled water into the channel at flow rates of 2.0, 4.0, 6.0 mL/hr. The micro-channels are fabricated with PDMS with a silicon mold, then O$_{2}$ -ion bonded onto a slide glass. Results show differences in flow characteristics and resolution according to fluid injection rates, and magnifications, respectively. The results include PIV data with vector-to-vector distances of 2 $\mu$m with 32 pixel-square interrogation windows at 50$\%$ overlap.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.423-426
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• 2002

A custom micro-PIV optics assembly has been used to measure the flow field inside a T-shaped microchannel. The micro-PIV system consists of microscope objectives of various magnifications, a dichroic cube, and an 8-bit CCD camera. Fluorescent particles of diameters 620nm have been used with a Nd:YAG laser and color filters. A programmable syringe pump with Teflon tubings were used to inject particle-seeded distilled water into the channel at flow rates of $420,\;40,\;60{\mu}L/hr$. The microchannels are fabricated with PDMS with a silicon mold, then $O_2-ion$ bonded onto a slide glass. Results show differences in flow characteristics and resolution according to fluid injection rates, and magnifications, respectively. The results show PIV results with vector-to-vector distances of $2{\mu}m$ with 32 pixel-square interrogation windows at $50{\%}$ overlap.

• Journal of the Korean Society of Visualization
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• v.4 no.2
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• pp.32-36
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• 2006

Recently there are many researches about single flow and two-phase flow phenomena in the mini and microchannel. But from this result the principle in the microchannel was not explained clearly. In this paper two-phase flow pattern was visualized in the micro-multi-branched-channel using a high speed camera. Microchannel was fabricated with PDMS and glass slide. The velocity profile was obtained by a Micro PIV. Then flow boiling at the near inlet area was occurred and vapor was moved in the micro-multi-branched-channel.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.392-401
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• 2006

In the July of 2006, devastating rainfalls ravaged the terrain in the province of Kangwon. These rainfalls resulted in debris flows, landslide and overflow over the habitat. Following these events, the urgent field study and countermeasures were to be needed and several methods were indicated. At each site, field observations were made and the properties of the channel and debris flow were broadly characterized. Debris flows are a natural hazard which looks like a combination of flood, land and rock slide. The same goes for that case, debris flow has been reported frequently overseas and the extent of damages has been increased. But the hazards "debris flow" is still insufficiently researched and futhermore debris flows are very hard to predict. In this paper, the general overview of the debris flow problem and the mitigation method will be presented

• 기술발표회
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• s.2006
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• pp.220-231
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• 2006

Debris flows are a natural hazard which looks like a combination of flood, land and rock slide. Large rainfall in July 2006 produced several large scale debris flows and many small debris flows that resulted in loss of life and considerable property and highway damage, as was widely reported in the national media. The hazard "debris flow" is still insufficiently researched Furthermore debris flows are very hard to predict. In this paper, a general over view of the debris flow problems along the highway, a generic way for the design and dimensioning of flexible barrier systems will be presented. A brief description of the various unique barrier types will be provided, too. The future for these barrier concepts looks promising because these barriers represent the state of art for such applications and are superior to many other available options.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.2
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• pp.157-164
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• 2017

A parallel slide gate valve (PSGV) is located between the heat recovery steam generator (HRSG) and the steam turbine in a combined cycle power plant (CCPP). It is used to control the flow of steam and runs with repetitive operations such as startups, load changes, and shutdowns during its operation period. Therefore, it is necessary to evaluate the fatigue damage and the structural integrity under a large compressive thermal stress due to the temperature difference through the valve wall thickness during the startup operations. In this paper, the thermal-structural analysis and the fatigue life evaluation of a 16-inch PSGV, which is installed on the HP steam line, is performed according to the fatigue life assessment method described in the ASME B&PVC VIII-2; the method uses the equivalent stress from the elastic stress analysis.

• Journal of the Korean GEO-environmental Society
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• v.9 no.5
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• pp.83-89
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• 2008

This study is to figure out the speed of soil diffusion and shapes as well when landslide occurred. It was measured the speed and shapes of soil diffusion using installed indoor-simulation of a land slide. Standard sand was used to measure it and this measurement is following the moisture content of standard sand. The result of this experiment follows the moisture content; as the moisture content goes up, the area and speed of soil diffusion goes faster as well. As the average of records by the moisture content was analyzed, the area and speed of land slide are increased proportionally. The shape of diffusion is formed as fanwise. It depends on the moisture content as above; the speed was fast when the moisture content is high, and it was getting narrower and longer as the speed of diffusion was faster.