• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.119-124
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• 2004

A water hammer mostly comes out when a valve fixed at the downstream end of the pipe-line system is rapidly closed or opened. A simple phenomenon of water hammer is often caused around us, and this phenomenon imperils the pipe systems occasionally. In this paper, we confirmed the phenomenon of water hammer by an experiment and forecasted a change of pressure in the pipe-line system by a numerical method. Also a vibration response, which is caused by water hammer, of the pipe-line system confirmed by an experiment and analyzed by a numerical method.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.1
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• pp.37-44
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• 1996

Water hammer pressure waves were measured in a simplified water piping system with and without arresters and air chambers by the operations of the solenoid valve. Experiments were performed to investigate the effects of the location of the arresters and the effects of the volume of the air chambers on maximum and minimum water hammer pressures and wave frequency for various flow rates.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.9
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• pp.2251-2256
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• 1994

An experimental study was conducted on water hammer phenomena generated by quick valve operations in piping systems of buildings. Transient water hammer pressure waves were measured for three different types of valves, i. e. a ball valve, a solenoid valve, and on one-touch valve. The effects of flow rate and valve closing time on the maximum water hammer pressure were investigated. Based on the experimental results, general design recommendations were provided to prevent water hammer phenomena in piping systems of high-rise apartment buildings.

• Nuclear Engineering and Technology
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• v.36 no.4
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• pp.285-294
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• 2004

Pressure wave propagation in the discharge piping with a sparger submerged in a water pool, following the opening of a safety relief valve, is analyzed. To predict the pressure transient behavior, a RELAP5/MOD3 code is used. The applicability of the RELAP5 code and the adequacy of the present modeling scheme are confirmed by simulating the applicable experiment on a water hammer with voiding. As a base case, the modeling scheme was used to calculate the wave propagation inside a vertical pipe with sparger holes and submerged within a water pool. In addition, the effects on wave propagation of geometric factors, such as the loss coefficient, the pipe configuration, and the subdivision of sparger pipe, are investigated. The effects of inflow conditions, such as water slug inflow and the slow opening of a safety relief valve are also examined.

• Journal of Korean Society of Steel Construction
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• v.11 no.3 s.40
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• pp.259-270
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• 1999

In this study, establishment of standard design procedure and optimum dimension of the embedded steel-plate cellular bulkheads for seawall structures in deep water sites has been presented. A computer program was developed to asses feasible dimensions of steel-plate cell, and general equations to determine optimum cell diameter and embedment depth are derived for sand. A model experiment to verify the necessary driving force of vibratory hammer system was also performed and driving force data pertinent to optimum cell dimension are presented.

• New & Renewable Energy
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• v.4 no.4
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• pp.37-43
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• 2008

Three properties of food waste are water 80%, ash 3%, volatile matter 17%. When food waste goes through treatment process such as removal of foreign substances, removal of water as well as sodium, dryness, and pulverization, it transforms into 4,000 Kcal/kg purverized fuel if moisture content is below 13%. Fuel ratio (fixed carbon/volatile matter) of purverized fuel is low compared with bituminuous coal. Ignition temperature measured by thermogravimetry analyzer is about $460^{\circ}C$. Combustion test of purverized fuel have been performed using energy recovery facility which include storage tank of dewatered cake, dryer, hammer mill, combuster including burner, boiler, flue gas treatment equipment. When 160-180 kg/hr of fuel is steadily supplied to burner for 3 hours, combustor temperature reaches about $1000^{\circ}C$ and CO is 77-103 ppm at 1.55 excess air ratio and SOx and Cl are under 2 ppm and 1ppm, respectively. This experiment demonstrate that purverized fuel made from food waste could be an alternative clean energy at the age of high oil price.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.149-152
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• 2008

Three properties of food waste are water 80%, ash 3%, volatile matter 17%. When food waste goes through treatment process such as removal of foreign substances, removal of water as well as sodium, dryness, and pulverization, it transforms into 4,000Kcal/kg purverized fuel if moisture content is below 13%. Fuel ratio(fixed carbon/volatile matter) of purverized fuel is low compared with bituminuous coal. Ignition temperature measured by thermogravimetry analyzer is about $460^{\circ}C$. Combustion test of purverized fuel have been performed using energy recovery facility which include storage tank of dewatered cake, dryer, hammer mill, combuster including burner, boiler, flue gas treatment equipment. When 160-180 kg/hr of fuel is steadily supplied to burner for 3 hours, combueter temperature reaches about $1000^{\circ}C$ and CO is 77-103ppm at 1.55 excess air ratio and SOx and Cl are under 2ppm and 1ppm, respectively. This experiment demonstrate that purverized fuel made from food waste could be an alternative clean energy for high oil price era

• Nuclear Engineering and Technology
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• v.51 no.4
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• pp.1008-1016
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• 2019

In the SG (steam generator) of PWR (pressurized water reactor) for a nuclear plant, hundreds of U-shaped tubes are used for the heat exchanger system. They interact with primary pressurized cooling water flow, generating flow-induced vibration in the secondary flow region. A simplified U-tube model is proposed in this study to apply for experiment and its counterpart computation. Using the commercial code, ANSYS-CFX, we first verified the Moody chart, comparing the straight pipe theory with the results derived from CFD (computational fluid dynamics) analysis. Considering the virtual mass of fluid, we computed the major modes with the low natural frequencies through the comparison with impact hammer test, and then investigated the effect of pump flow in the frequency domain using FFT (fast Fourier transform) analysis of the experimental data. Using two-way fluid-structure interaction module in the CFD code, we studied the influence on mean flow rate to generate the displacement data. A feasible CFD method has been setup in this research that could be applied potentially in the field of nuclear thermal-hydraulics.