• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.21 no.6
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• pp.451-465
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• 1992

• Journal of Korean Society of Water and Wastewater
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• v.22 no.6
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• pp.609-617
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• 2008

Water pipes are supposed to deliver the predetermined demand safely to a certain point in water distribution system. However, pipe burst or crack can be happened due to so many reasons such as the water hammer, natural pipe ageing, external impact force, soil condition, and various environments of pipe installation. In the present study, the reliability model which can calculate the probability of pipe breakage was developed regarding unsteady effect such as water hammer. For the reliability model, reliability function was formulated by Barlow formula. AFDA method was applied to calculate the probability of pipe breakage. It was found that the statistical distribution for internal pressure among the random variables of reliability function has a good agreement with the Gumbel distribution after unsteady analysis was performed. Using the present model, the probability of pipe breakage was quantitatively calculated according to random variables such as the pipe diameter, thickness, allowable stress, and internal pressure. Furthermore, it was found that unsteady effect significantly increases the probability of pipe breakage. If this reliability model is used for the design of water distribution system, safe and economical design can be accomplished. And it also can be effectively used for the management and maintenance of water distribution system.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.511-516
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• 2005

This study is to investigate the pressure wave characteristics and the maximum pressure rise generated by instantaneous valve closure at the end of the straightening polybutylene double piping system with header. Experiments were conducted under the following conditions: initial pressure $1{\sim}5$ bar, flow velocity $0.5{\sim}3.0$ m/s and water temperature $25^{\circ}C$.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.431-437
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• 1996

The natural frequencies of annular plates in contact with water were theoretically derived and its validity was checked by experiments. The experimental frequency response functions of the annular plates were obtained using the impact hammer method. Comparison of the FRF obtained using the impact hammer and the fRF using shaker attached showed that the former was better than the latter due to the mass effect and additional constraint from the instrumentation. It was found that the experimentally extracted natural frequencies of annular plates in contact with water were in good agreement with those theoretical values.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.7
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• pp.380-385
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• 2009

This study is to investigate the pressure wave characteristics and the maximum pressure rise generated by instantaneous valve closure at the end of the straightening polybutylene double piping system with header. Experiments were conducted under the following conditions: initial pressure $0.1{\sim}0.5$ MFa, flow velocity $0.5{\sim}3.0$ m/s and water temperature $25^{\circ}C$.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.25 no.5
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• pp.387-393
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• 1996

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.25 no.5
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• pp.379-386
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• 1996

• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.251-251
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• 2003

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.2
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• pp.164-174
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• 2007

Phenomena of hydraulic transient such as water hammer should be analyzed to design the pipeline systems effectively in dam. Surge tanks generally are used to reduce change in pressure caused by hydraulic transient from load changes on the turbines. In this study, the appropriate scale of surge tank with chamber is investigated for dam safety management. The variation of water level in the surge tank are computed using governing equation. Using the Thoma-Jaeger's stability condition, static and dynamic stability are investigate for the cases of flood water level, normal high water level, rated water level and low water level. Finally appropriate diameters of shaft and chamber are determined in the surge tank with chamber.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.285-286
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• 2005