• Proceedings of the KWS Conference
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• 1998.10a
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• pp.121-124
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• 1998

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.112-112
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• 1998

No Abstract, See Full Text

• Proceedings of the Korean Nuclear Society Conference
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• 2003.10a
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• pp.129.1-129.1
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• 2003

• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.229.1-229
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• 1999

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2261-2266
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• 2007

In this study, the numerical analysis to estimate condensation heat and mass transfer of the condenser was carried out using the PMA (porous medium approach). In the PMA, the details of tube bundle in the condenser are replaced by the porous medium, and the flow resistance term is added in the momentum equation. In this regard, the PMA is quite helpful for the study of tube bundle in the large condenser. The pressure loss through tube bundle can be compensated by viscous and inertial momentum sink terms, which was validated numerically. Value of the pressure drop was compared to that of Butterworth correlation. Three dimensional analysis of condensation for McAllister condenser with the PMA was conducted using Fluent 6.2 and UDFs (use-defined functions). The result of condensation rate was analogous to previous results (experimental and numerical data).

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.6 no.1
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• pp.65-71
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• 2010

The plugging rate of reheater tubes of Wolsung unit 1 nuclear power plant has been increased by corrosion and erosion since 1990. As the dimensions of the new first stage reheater bundle tubes which were supplied by Hanjung company to replace were different from old one, numerical calculations are carried out for flow and heat transfer in the reheater bundle tubes of the N.P.P. Numerical calculations consists of thermal performance, drain line pressure drop, flow change by pressure drop of line, stress analysis of finned tubes and analysis of flow induced vibration. Computational analysis using heat transfer research institute program is adopted to verify the results of the numerical calculations. It contains the evalution of performance in the system with view to location of the new reheater bundle and it shows the differences between the numerical calculation results and heat transfer research institute program output.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.2
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• pp.304-310
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• 2001

This paper describes the analysis of flow field using a projection finite element method. The projection scheme with a pressure correction is presented for the analysis of an incompressible Navier-Stokes flow. The projection scheme is analyzed numerically and applied to the well-known bench marking problems such as lid driven cavity. Finally, the projection scheme is applied to a flow through the automobiles front. In the automobiles cooling system, the flow through its front is very important to a cooling performance. The results show that the flow quantity increases by locating the position of bumper to the further front position of a car. And, the improvement on the suction part below a bumper achieves the more passing flow quantity. The attachment of an air dam increases passing flow quantity causing the pressure rise to the front part and the pressure drop beneath a car.

• Journal of Power System Engineering
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• v.20 no.1
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• pp.5-10
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• 2016

Swing check valve is opened when the flow direction is forward, when the flow is reversed, the valve is automatically closed by back pressure. In this study, the internal flow field analysis of the valve was conducted by Fluent. The working fluid used in the study, using liquefied methane $-165^{\circ}C$ (CH4) and velocity field, pressure field, pressure drop coefficient were simulated by varying separately the opening divergence into four intervals from 0 to 100%. The approximate research result are as follow : When the opening divergence is smaller, it appears high pressure on the upstream side, this value is relaxed when the opening divergence is large. Flow rate coefficient of the valve shows a larger value as the degree of opening becomes larger, confirming that the check valve used in the study is in the effective flow rate counting range.

• Journal of Power Electronics
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• v.1 no.1
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• pp.9-18
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• 2001

The performance analysis of a three-phase parallel active power filter that compensates PCC voltage and the unbalanced loads is presented in this paper. The proposed scheme in this paper employs a PWM voltage-source inverter and has two operation modes. Firstly, it operates as a conventional active filter with reactive power compensation when PCC voltage is within the 15% voltage drop range. Secondly, it operates as a voltage compensator when PCC voltage is not within the 15% voltage drop range. And both APF and voltage compensator compensate asymmetries caused by nonlinear loads. Finally, two methods of detecting the negative sequence are reviewed, and the validity of this scheme is investigated through analysis of simulation and experimental results for a prototype active power filter system rate at 10KVA.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.8
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• pp.112-119
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• 2002

Three dimensional numerical heat transfer analysis was carried out against periodically arranged fuel injectors of the liquid rocket engine. A finite volume method based on SIMPLE algorithm was adapted which gave a good agreement with the published results of the heat transfer problem of a backward facing step. The Nusselt number and pressure drop increased as the distance between the injector elements decreased. When the Reynolds number increased, the Nusselt number increased but nondimensionalized pressure drop decreased slightly.