• Fire Science and Engineering
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• v.32 no.1
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• pp.24-32
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• 2018

There are two kinds of method on hydraulic calculation of fire sprinkler system design. The one is using the computational program and the other is designer calculate system for oneself. In case of using the computational program, putting the input data in, the program calculate the friction loss, water flow, total height and so forth. If program user or designer doesn't know the basic idea and procedure of hydraulic calculation. Then, the outputs are different from each other. This paper suggests the hydraulic calculation procedure in design area as follow. Equivalent lengths of tees on the branch are selected base on the same pipe diameter which the tees are established, although the diameter of tee outlet is different. Even though there is a different friction loss of head from the other head, the pressure from the hydraulic end is bigger than a head loss, discharge flow is calculated by pressure from the hydraulic end.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.705-712
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• 2000

The fluid generally flows through fractures in crystalline rocks where most of underground storage facilities are constructed because of their low hydraulic conductivities. The fractured rock is better to be conceptualized with a discrete fracture concept, rather continuum approach. In the aspect of fluid flow in underground, the simultaneous flow of groundwater and gas should be considered in the cases of generation and leakage of gas in nuclear waste disposal facilities, air sparging process and soil vapor extraction for eliminating contaminants in soil or rock pore, and pneumatic fracturing for the improvement of permeability of rock mass. For the purpose of appropriate analysis of groundwater-gas flow, this study presents an unsteady-state multi-phase FEM fracture network simulator. Numerical simulation has been also conducted to investigate the hydraulic head distribution and air tightness around Ulsan LPG storage cavern. The recorded hydraulic head at the observation well Y was -5 to -10 m. From the results obtained by the developed model, it shows that the discrete fracture model yielded hydraulic head of -10 m, whereas great discrepancy with the field data was observed in the case of equivalent continuum modeling. The air tightness of individual fractures around cavern was examined according to two different operating pressures and as a result, only several numbers of fractures neighboring the cavern did not satisfy the criteria of air tightness at 882 kPa of cavern pressure. In the meantime, when operating pressure is 710.5 kPa, the most areas did not satisfy air tightness criteria. Finally, in the case of gas leaking from cavern to the surrounding rocks, the resulted hydraulic head and flowing pattern was changed and, therefore, gas was leaked out from the cavern ceiling and groundwater was flowed into the cavern through the walls.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.891-895
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• 1996

Performance and efficiency of hybrid (hydraulic-mechanical) pick-up device of deep sea manganese nodules collector are very sensitive to altitude and altitude of pick-up head relative to undulating seafloor. For this reason, motion control of pick-up head relative to the changing deep sea topography and other disturbances is of particular importance in design of pick-up device. The concept of design axiom is applied to a pick-up device of hybrid type. Kinematic analysis conducted in absolute Cartesian coordinates gives position, velocity, and acceleration of the hydraulic cylinders which enable the pick-up head to keep the preset optimal distance from seafloor. Inverse dynamic analysis provides the driving forces of hydraulic cylinders and the reaction forces at each joint. Design sensitivity analysis is performed in order to investigate the effects of possible design variables on the change of the maximum strokes of hydraulic cylinders. The direct differentiation method is used to obtain the design sensitivity coefficients.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.5
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• pp.334-339
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• 2013

A pilot-scale sand-box experiment simulating a lateral of collector well used in riverbank filtration was performed, and hydraulic head distributions along the lateral were measured according to the various drawdowns at the well. The results of this experiment were compared to the predicted values obtained using a theory previously developed by Kim in order for its validation. This theory predicts the head loss in a large-scale lateral given the loss in a small-scale one, and to have actual values for comparison, the results from a lab-scale experiment previously performed by Kim were employed. Comparing the experimental values to the extrapolated value indeed confirmed the validity of the theory. A procedure to determine the hydraulic head distribution of a practical-scale lateral was also presented applying the theory to the experimental result of this study in an effort to show the process of lateral design for riverbank filtration.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.664-667
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• 2009

The Francis type hydro turbine with vertical axis has been designed and analized for hydraulic performance verification. The guide vane angle of turbine casing were designed to be varied according to the condition of head and flowrate. When the changes in flowrate and output were comparatively large, the efficiency drop were small, so the efficiency characteristics and stability of the entire operating condition were maintained in good condition. These results showed that the developed hydro turbine in this study will be suitable for small hydro power stations with medium and high head such as agricultural reservoirs and large dam.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.523-526
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• 2006

A series of hydraulic and cavitation tests are performed in water environment in order to verify the hydraulic and cavitation performance of three types of LOX pumps. All the performances of the pumps are found to be satisfied with each design requirement. In the hydraulic tests, the head and efficiency are increased as the gap between floating ring seals and the impeller shoulder is decreased. In the cavitation tests, some pumps show decrease in the cavitation performance as the flowrate of the pump is decreased.

• Magazine of the Korean Society of Agricultural Engineers
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• v.14 no.1
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• pp.2557-2569
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• 1972

Hydraulic computations to determine the elevation of canal bottom and mater surface for box type concrete culverts are discussed. Velocity and cross sectional area of flow are computed from Manning's formula. Aad then head loss and velocity head are considered to determine the elevation of bottom and water surface. For stress analysis, 13.5 ton live load and earth pressure are considered. Also longitudinal stress of box culverts is checked.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.379-382
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• 2008

The propeller type hydro turbine model with vertical axis has been tested and analized. The blade angle of runner of turbine model were designed to be varied according to the condition of head and flowrate. When the changes in head and output were comparatively large, the efficiency drop were small, so the efficiency characteristics and stability of the entire operating condition were maintained in good condition. These results showed that the developed model in this study will be suitable for small hydro power stations with large changes in head and load such as sewage treatment plants and agricultural reservoirs.

• Transactions of the Korean hydrogen and new energy society
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• v.14 no.2
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• pp.171-176
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• 2003

The propeller type hydro turbine model with vertical axis has been tested and analyzed. The blade angle of turbine model were designed to be varied according to the condition of head and flowrate. When the changes in head and output were comparatively large, the efficiency drop were small, so the efficiency characteristics and stability of the entire operating condition were maintained in good condition. These results showed that the developed model in this study will be suitable for small hydro power stations with large changes in head and load such as sewage treatment plants and agricultural reservoirs.

• The Journal of Engineering Geology
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• v.25 no.2
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• pp.291-298
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• 2015

For hydrogeological studies, it is of importance to observe hydraulic head in order to interpret groundwater flow, characterize aquifers, and calibrate groundwater flow model. This study analyzed the zonal variation of hydraulic heads at the eight monitoring wells (GM-1~GM-8) installed with multi-packers in a coastal area and verified vertical and lateral trends of the hydraulic gradients. Hydraulic heads were expressed as the depth of water because the monitoring wells have different depths. The hydraulic gradient at the nearest well (GM-5) shows 0.0142 with increasing trend of hydraulic gradient along depth. This fact indicates typical phenomenon of the discharge area. On the other hand, GM-1 and GM-2 wells in coastal area demonstrate constant hydraulic gradient down to the depth of 100 meters while at the zone of deeper than 100 m the hydraulic gradients illustrate 0.0196 and 0.0735, respectively. This indicates that horizontal flow is dominant at shallower zone than 100 m whereas upward flow is dominant at the zone deeper than 100 m. GM-3 well located farther than the other wells from the coast shows a small hydraulic gradient of 0.0046 that evidences a prevalent horizontal flow between the recharge area and the discharge area.