• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.5
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• pp.579-586
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• 2019

Pilot Point Method (PPM) is one of the popular methods to search hydraulic conductivities in the inverse method using groundwater flow equations. In this study, the Simultaneous Search based Pilot Point Method (SSBM) was applied with diverse information (e.g. hydraulic heads and/or tracer concentration) applications over previously developed sensitivity based Pilot Point Method (e.g. D-optimality based Pilot Point Method: DBM). In the case of DBM, due to the minimized the variance size, tracer concentration can be recognized as a tool to control the searching space of hydraulic conductivities. SSBM reduced the procedure of hydraulic conductivity searching, though it produced more variance for exploring hydraulic conductivities. In addition, SSBM was dependent on the initial hydraulic conductivity values for search finalized hydraulic conductivities. When tracer concentration was applied, searching hydraulic conductivities was more preferable than only when hydraulic head was applied. Applications of various data for searching hydraulic conductivities is recommended as a more efficient way.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.5
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• pp.77-85
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• 1999

Irrigation pipeline systems have been recently adopted for irrigation purposes, which was thought to improve irrigation efficiencies. However, if hydraulic characteristics are not evaluated in designing , overpressure due to waterhammer may occur and result in serious problems. Therefore, in this study a model was formulated to simulate unsteady motion of water in a pipeline resulting from valve closure, the applicability of the model owas tested with fiedld data, and the results showed good agreement in maximum piezometric head. Also, simulated maximum piezometric head was compared with designed piezometric head computed by empirical method, and maximum piezometric head in a pipeline resulting from valve closure was simulated and analyzed with varing surge tank's position and diameter.

• Transactions of Materials Processing
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• v.14 no.6 s.78
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• pp.565-569
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• 2005

Reactor Vessel is one of the most important structural parts of nuclear power plant. It is manufactured by various steel forgings such as shell, head and transition ring. Head forgings have been made by open die forging process. After steel melting and ingot making, open die forging has been carried out to get a good quality which means high soundness and homogeniety of the steel forgings by using high capacity hydraulic press. This paper introduced the open die forging process and manufacturing experience of large head forgings which can be used for the reactor vessel of 1,000MW nuclear power plant.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.06a
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• pp.131-139
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• 2005

Reactor Vessel is one of the most important structural part of nuclear power plant. It is manufactured by various steel forgings such as shell, head and transition ring. Head forgings has been made by open die forging process. After steel melting and ingot making, open die forging has been carried out to get a good quality which means high soundness and homogeniety of the steel forgings by using high capacity hydraulic press. This paper introduced the development trend of the open die forging process and manufacturing experience of large head forgings which canl be used for the reactor vessel of nuclear power plant.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.397-400
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• 2005

Reactor Vessel is one of the most important structural part of nuclear power plant. It is manufactured by various steel forgings such as shell, head and transition ring. Head forgings has been made by open die forging process. After steel melting and ingot making, open die forging has been carried out to get a good quality which means high soundness and homogeniety of the steel forgings by using high capacity hydraulic press. This paper introduced the open die forging process and manufacturing experience of large head forgings which cant be used for the reactor vessel of 1,000MW nuclear power plant.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.655-659
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• 2004

Performance tests of the fuel pump for a turbopump unit have been successfully carried out in water environment. The tests are performed to evaluate the hydraulic and cavitation performances. The head and volute pressure distribution of the fuel pump followed the conventional similarity rule - unlike this, the secondary passage pressure distribution showed a small deviation from the conventional similarity rule. Also, critical cavitation number decreased as the rotational speed of the pump increased.

• KCID journal
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• v.3 no.2
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• pp.44-52
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• 1996

To make a real hydraulic simulation model, Hazen-Williams' coefficient must be calibrated using the measured discharges and hydraulic head loss. In this paper, calibrating method of Hazen-Williams' coefficient was proposed for pipeline system. The calibra

• Journal of the Korean Geotechnical Society
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• v.25 no.9
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• pp.101-106
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• 2009

In this study we analyzed the seepage characteristics of meandering section of rivers commonly seen in domestic terrain. The seepage analysis is designed to be more realistic by considering a tangent and meandering section of levee. The levee was idealized to reflect the relevant characteristics by considering the curved angle of 90 degrees and 130 degrees in the spatial frequencies, water elevation conditions, and hydraulic conductivities. Seepage analysis becomes more detailed and precise with the seepage curve shape which is interpreted to indicate the flow of three-dimensional numerical analysis program using VisualFEA. As a result of the analysis, it is shown that the water level in the straight levee was constant, regardless of hydraulic conductivities, and the total head in the meandering section was increased by the overlapping of seepage. Consequently, it is found that the total head was increased more significantly in the case of 90 degrees curved levees than 130 degrees, and the total head showed similar characteristics In the straight levee.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2002-2010
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• 2024

Korea Atomic Energy Research Institute (KAERI) has operated an integral effect test facility, the Advanced Thermal-Hydraulic Test Loop for Accident Simulation (ATLAS), with reference to the APR1400 (Advanced Power Reactor 1400) for tests for transient and design basis accidents simulation. A test for a loss of coolant accident (LOCA) at the top of the reactor pressure vessel (RPV) had been conducted at ATLAS to address the impact of the loss of safety injections (LSI) and to evaluate accident management (AM) actions during the postulated accident. The experimental data has been utilized to validate system analysis codes within a framework of the domestic standard problem program organized by KAERI in collaboration with Korea Institute of Nuclear Safety. In this study, the test has been analyzed by using thermal-hydraulic system analysis codes, MARS-KS 1.5 and TRACE 5.0 Patch 6, and a comparative analysis with experimental and calculation results has been performed. The main objective of this study is the investigation of the thermal-hydraulic phenomena during a small break LOCA at the RPV upper head with the LSI as well as the predictability of the system analysis codes after the AM actions during the test. The results from both codes reveal that overall physical behaviors during the accident are predicted by the codes, appropriately, including the excursion of the peak cladding temperature because of the LSI. It is also confirmed that the core integrity is maintained with the proposed AM action. Considering the break location, a sensitivity analysis for the nodalization of the upper head has been conducted. The sensitivity analysis indicates that the nodalization gave a significant impact on the analysis result. The result emphasizes the importance of the nodalization which should be performed with a consideration of the physical phenomena occurs during the transient.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.4
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• pp.55-61
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• 2019

Motor pumps cannot be used in those areas where electricity is not accessible such as remote rural areas in many African countries. Hydraulic ram pump is one of the solutions for supplying water for irrigation or domestic uses. The hydraulic ram pumps are working based on the water hammer effect for pumping without external power or electricity. This study was conducted to investigate the effect of air chamber volume and operation parameters on the performance of the hydraulic ram pump which was assembled with common plumbing parts. The experimental results showed the volume of the air chamber did not affect the performance such as discharge rate and head. When drive heights were 1.7 and 2.35 m, the maximum discharge heads were up to 7 m and 10 m, respectively. When the air chamber volume was 1 L, discharge rates were 0.23 and 2.12 L/min under the drive heights of 1.7 and 2.35 m, respectively. The average energy efficiency of the hydraulic ram pump assembled in this study was about 60% for all the experimental conditions.