• Journal of the Society of Naval Architects of Korea
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• v.46 no.5
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• pp.545-551
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• 2009

In naval architecture and offshore engineering, the development and a broad use has been achieved in the field of flow control valves for pipe system. Butterfly valves are also widely used for flow control, but there are not many studies for triple-eccentric butterfly valves. Moreover, if the fluid of pipeline flows in the bi-direction then it makes more complicate to adapt triple-eccentric butterfly valves to flow control. In this study, we are trying to develop a bi-directional triple-eccentric butterfly valve through sealing mechanism and stem design study. Digital mockup using 3D CAD was constructed for shape interference check and structural analysis was conducted for structural safety. Also we performed leakage test to check out the durability of the bi-directional pressure for the developed valve.

• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.105-109
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• 2008

A safety valve has a valve mechanism for the automatic release of gas from piping system when the pressure exceeds preset limit cause of a defect of a pressure regulator, condensation of water in a pipe. Therefore, for the safety of pressure regulating station, it is essential to study the flow regime and characteristics of safety valve. This article presents the numerical analysis on the flow analysis, the ejection capacity and required effective discharge area of the safety valve that is established in pressure regulating station. Then, the results are compared and analyzed with domestic and foreign regulations such as API(America Petroleum Institute), EN(European Standard), and NF(Norme Francise). Moreover, the installation number of safety valve is considered by using domestic and foreign regulations and maximum reguired effective discharge area of safety valve.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.1
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• pp.1-6
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• 2017

Surge pressure is created by rapid change of flow rate due to operation of hydraulic component or accident of pipeline. Proper control of surge pressure in distribution system is important because it can damage pipeline and may have the potential to degrade water quality by pipe leakage due to surge pressure. Surge relief valve(SRV) is one of the most widely used devices and it is important to determine proper parameters for SRV's installation and operation. In this research, determining optimum parameters affecting performance of the SRV were investigated. We proposed the methodology for finding combination of parameters for best performance of the SRV. Therefore, the objective function for evaluate fitness of candidate parameters and surge pressure simulation software was developed to validate proposed parameters for SRV. The developed software was integrated into genetic algorithm(GA) to find best combination of parameters.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.7
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• pp.1408-1418
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• 1992

The valve timing and intake system in SI engine is chosen in order to get the maximum performance at the target rpm. This is a compromise and the performance reduction is expected in a certain rpm range. Therefore, to accomplish the possible engine capacity all over the operation ranges, it is required to investigate the effects of intake system and valve timing on engines more thoroughly. In this paper, it was attempted to examine closely the combined effects on the torque and the volumetric efficiency due to the change of valve timing and intake system dimensions. For this, the inlet port pressure was chosen as a primary parameter to represent engine performance characteristics together with surge tank pressure and induction pressure as secondaries. The inlet port pressure was analyzed in connection with both the secondaries and the performance data. Especially the relation between the inlet port pressure and the torque and volumetric efficiency was investigated on the operating conditions. In this experiment, it was acquired that the performances at specific rpm range could be improved by the combinations of valve timing and intake system. Then it was verified that pressure at a intake system contained useful data for the engine performance. By the analysis of inlet port pressure with the others, it was obtained that the properties of the torque and the volumetric efficiency due to the change of valve timing and intake conditions were able to be defined by the average and the maximum inlet port pressures, the pressure near before the intake valve closing(IVC) point as well as the pressure at IVC point during the intake valve opening duration. These results could be applied to almost all over the experimental conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.50-55
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• 2015

This study examined the relationship between the shape of the inside of the PRV and the cavitation of the water supply system of an apartment house. In this paper, nine types of PRV with different gaps and shapes were analyzed numerically using a 3D model embedded in the commercial code, ANSYS-CFX. The lowest pressure and the maximum velocity occurred at the narrow gap, which is located at the between the stem and the disk. When the gap size was increased, the vapor volume fraction was always greater than 0, but the vapor volume fraction of the type of expansion pipe approached 0. These results indicate that the cavitation of PRV can be reduced by a shape change to the type of expansion pipe.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.1
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• pp.179-188
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• 1990

The characteristic of volumetric efficiency considering gas exchange process in a reciprocating engine is presented in this paper. The characteristic method is used for solving gas exchange problems of engine system in theoretical studies. The validity of the simulation is investigated by a comparison with the results obtained by the experiment which have been performed on the practical 4-cycle, 4-cylinder gasoline engine. The relationship between the volumetric efficiency and the intake pressure variation according to configuration of intake pipe, position of branch point, valve timing, compression ratio is clarified through simulation and experiment. The results predicted by the simulation are found to be in approximate agreement with those obtained by the experiment.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.271-278
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• 1997

The flow of steam through a safety valve vent pipe system in the boiler has been analyzed to provide a design basis of diffuser silencer for attenuating shock-shell and jet noise. Numerical analysis to estimate inner fluid of silencer and noise propagation outside silencer are performed. The distribution curve of fluid information to provide average values about inner fluid of silencer is presented by theoretical analysis.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.1
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• pp.38-41
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• 2014

Fixture units and the diversity curve are used, in order to determine the required size of water supply pipe. However, the values of the National Plumbing Code, International Plumbing Code and National Standard Plumbing Code of America are not the same. The objective of this study is to comparatively analyze the fixture units and the peak flows of a 10th story office building, at any instant of time, according to the three codes.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.5
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• pp.66-73
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• 1994

The configuration effects of a tumble adaptor which transforms tumble into swirl on the intake tumble characterization under steady flow condition have been investigated by LDV measurement The following parameters were involved to test their effects on tumble-swirl conversion characteristics ; the cylinder height and its bottom shape, measuring position in the swirl induction pipe, and the relative direction of the induction pipe. The short cylinder height and the flat bottom of the tumble adaptor were found effective for the generation of tumble in the cylinder, allowing higher tumble-swirl conversion efficiency.

• Journal of Power System Engineering
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• v.13 no.4
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• pp.11-17
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• 2009

This paper deals with the effects of pulsating flow on volumetric efficiency, which may be generated during the gas exchange procedure, due to piston motion, valve event on intake and exhaust stroke and unsteady flow of turbocharger of a three-cylinder four stroke turbo-charged diesel engine. Consequently, volumetric efficiency affects significantly the engine performance; torque characteristics, fuel economy and further to emission and noise level. As the expansion ratio became larger the engine speed varies and torque increases, the pressure pulsation in an exhaust gas pipe acts as an increasing factor of intake air charging capacity totally. The phase and amplitude of pressure pulsation in the intake system only affects volumetric efficiency favorably, if it is well matched and tuned effectively to the engine. Thus, to verify the exact phase and amplitude of the pressure variation is the ultimate solution for the air-flow ratio assessment in the intake stroke. Some experimental results of pressure diagrams in the intake pipe and gas-flow of turbine in-outlet are presented, under various kinds of operating condition.