• Journal of Industrial Technology
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• v.16
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• pp.31-38
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• 1996

This experimental study was conducted to analyze the characteristics of centrifugal pipes which were made of silica fume concrete. External load tests showed that maximum external load ranged from 1,100~5,300kgf/m with thickness ratio(t/D) of between 4.5%~10.0%. Correlation between thickness ratios and external loads was excellent with $R^2$ of 0.99. Respective correlation between measured and computed vertical deformation was good with $R^2$ of higher than 0.90. And therefore, vertical deformation and tensile stress of centrifugal concrete pipes may be theoretically computed with a good precision.

• Nuclear Engineering and Technology
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• v.39 no.5
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• pp.617-626
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• 2007

A centrifugal atomization process for uranium fuel was developed in order to fabricate high uranium density dispersion fuel for advanced research reactors. Spherical powders of $U_3Si$ and U-Mo were successfully fabricated and dispersed in aluminum matrices. Thermal and mechanical properties of dispersion fuel meat were characterized. Irradiation tests at the research reactor HANARO confirm the excellent performance of high uranium density dispersion fuel.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.2
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• pp.87-95
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• 2013

The aim of this study is to examine the behavior of reservoir fill dam with the water level raising by use of the centrifugal model test and the numerical simulation. In this study, LIQCA2D-SF based on the cyclic elasto-plastic constitutive model proposed by Oka et al. (1999) is applied for numerical simulation. In order to investigate the displacements and the pore water pressures in the fill dam due to the water level raising velocity, three model tests in centrifugal field of 50g for fill dams were conducted. A comparison between the test result and the simulation result has provided the influence on the displacement and the pore water pressure of the fill dam with increasing up of the water level.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.3
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• pp.91-100
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• 2016

Recently, lots of damages have been lost because large magnitude earthquakes were occurred in the world. It has been increased the number of earthquakes in Korea. It needs improvement required for the repair of deteriorated reservoirs, reinforcement and raised reservoir coping with climate change and earthquake. This study aims to investigate the seismic behavior of deterioration reservoir levee using dynamic centrifugal model test. Therefore, two case tests in centrifugal field of 60 g, the result has provided the influence on the acceleration response, displacement, settlement and the pore water pressure of the reservoir with earthquakes. From the results larger displacement and acceleration response at the front side of reservoir embankment with poor-fabricated core in seismic condition may degrade overall stability. Reasonable reinforcement method of the raised reservoir embankment is required for ensuring long-term stability on earthquake.

• Journal of the Korean Society of Safety
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• v.13 no.3
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• pp.135-142
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• 1998

This paper is to investigate the failure surface and modes in a soil mass by a excavation of the model ground. To study the failure surface for the excavated slope, centrifugal model tests were performed by changing the angle of the excavated slope(50, 75, $90^{\circ}$) and the ground condition($D_r$=60, 90%, dry and submerged ground). Excavation was simulated during the centrifuge tests by operating a valve that allowed the zinc chloride solvent to drain from the excavation. Results of model tests were compared with those obtained with theoretical solutions using limit equilibrium analysis method. The results of model tests show that, there is a failure to create a straight line in the low angle of excavated surface and a create a circle as the angle increases. Also, as the angle of excavated surface is increasing, the angle of the failure surface increases. The failure length in the submerged ground increases approximately 1.10~1.34 times more than that of the dry ground.

• International Journal of Fluid Machinery and Systems
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• v.4 no.3
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• pp.317-323
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• 2011

Mini centrifugal pumps having a diameter smaller than 100mm are employed in many fields; automobile radiator pump, ventricular assist pump, cooling pump for electric devices and so on. Further, the needs for mini centrifugal pumps would become larger with the increase of the application of it for electrical machines. It is desirable that the mini centrifugal pump design be as simple as possible as precise manufacturing is required. But the design method for the mini centrifugal pump is not established because the internal flow condition for these small-sized fluid machines is not clarified and conventional theory is not suitable for small-sized pumps. Therefore, we started research on the mini centrifugal pump for the purpose of development of high performance mini centrifugal pumps with simple structure. Three types of rotors with different outlet angles are prepared for an experiment. The performance tests are conducted with these rotors in order to investigate the effect of the outlet angle on performance and internal flow condition of mini centrifugal pumps. In addition to that, the blade thickness is changed because blockage effect in the mini centrifugal pump becomes relatively larger than that of conventional pumps. On the other hand, a three dimensional steady numerical flow analysis is conducted with the commercial code (ANSYS-Fluent) to investigate the internal flow condition. It is clarified from the experimental results that head of the mini centrifugal pump increases according to the increase of the blade outlet angle and the decrease of the blade thickness. In the present paper, the performance of the mini centrifugal pump is shown and the internal flow condition is clarified with the results of the experiment and the numerical flow analysis. Furthermore, the effects of the blade outlet angle and the blade thickness on the performance are investigated and the internal flow of each type of rotor is clarified by the numerical analysis results.

• Journal of the Korean Society of Safety
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• v.21 no.4 s.76
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• pp.85-94
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• 2006

In this study, in order to evaluate the effect of two types of connector systems in reinforced retaining wall, the centrifugal tests for the conventional connector and new settlement connector system were performed. In the centrifugal tests, the aluminum plate for the face was used and the aluminum foil was used as a reinforcement. The granite soil was adopted as a fill. As a result, The settlement reinforced retaining wall reached to the failure at 80g-level. In contrast, the conventional reinforced retaining wall was collapsed at 69g-level. It means that the settlement reinforced retaining wall has the stronger stability than the conventional reinforced retaining wall. In addition, it was shown that the settlement connector system is more effective to release the stress concentration occurred at the face of reinforced retaining wall than the conventional connector system.

• Journal of the Korean Society of Safety
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• v.12 no.3
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• pp.139-146
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• 1997

In this study, centrifugal model tests were performed to investigate the behavior of excavated earth retaining wall with the depth of excavation and different types of wall(aluminum, steel panel). Jumunjin standard sand was used for foundation soil. The raining method was adopted to form the required relative density of the model ground. The lateral earth pressure measured from tests were compared with estimated active earth pressure by Rankine's theory. The test results have shown that the earth pressure acting on the retaining wall and the rotation displacement of the wall are influenced by the depth of excavation and the type of wall. It was found from the test results that the deformation of the wall increases with the depth of excavation.

• 기술발표회
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• s.2006
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• pp.156-161
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• 2006

Recently, construction of soil-reinforced segmental retaining walls which used geosynthetics are being increased day by day due to its construction efficiency, economic efficiency, and its aesthetic view. The conventional reinforced earth retaining wall has the connector system to fix the reinforcement and block However, this system may cause the crack of block and the rupture of reinforcement due to the stress concentration near the face of reinforced earth retaining wall In this study, the new connector system, which is able to allow the settlement of reinforcement, was applied to analyze the effect of connector system of reinforced earth retaining wall The connection strength tests and centrifugal tests for both the conventional reinforced earth retaining wall and the settlement reinforced earth retaining wall were performed to compare the results

• Journal of the Korean Geotechnical Society
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• v.20 no.8
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• pp.135-145
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• 2004

In this study, the behavior of unpropped diaphragm walls on decomposed granite soil was investigated through centrifugal and numerical modelling. Centrifuge model tests were performed by changing the interval distance of surcharge. Excavation was simulated during the centrifuge tests by operating a solenoid valve that allowed the zinc chloride solution to drain from the excavation. In these tests, ground deformation, wall displacement and bending moment induced by excavation were measured. FLAC program which can be able to apply far most geotechnical problems was used in the numerical analysis. In numerical simulation, Mohr-Coulomb model fur the ground model, an elastic model for diaphragm wall were used for two dimensional plane strain condition. From the results of model tests, failure surface was straight line type, the ground of retained side inside failure line had downward displacement to the direction of the wall, and finally the failure was made by the rotation of the wall. The angle of failure line was about 67 ∼ 74$^{\circ}$, greater than calculated value. The locations of the maximum ground settlement obtained from model tests and analysis results are in good agreements. The displacement of wall and the change of the embedment depth is likely to have linear relationship.