• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 춘계 학술대회논문집
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• pp.68-71
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• 2007

An optimized bidet nozzle design to form the required swirl water jet is proposed with the help of numerical analysis. The bidet can do the cleaning process of human body by water injection and the speed/pressure/injection angle/magnitude of swirl intensity of water jet determine the cleaning capability and personal subjective feeling. The objective of this research is to design optimal water injection nozzle to make stable swirl intensity. The effect of individual design variables are analyzed from the basic design and the final design is deduced to make high performance water jet within the pre-determined operation conditions.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 춘계 학술대회논문집
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• pp.149-152
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• 2007

The numerical simulations on the heat transfer and flow field were carried out for the improvement of the performance of the shell and tube heat exchanger. The steady incompressible 3-D Navier-Stokes solution is obtained with the actual operational condition and geometry of the heat exchanger. The present geometry of the heat exchanger causes poor heat transfer since the air inside shell dose not flow through the tube bundle, but around it. The enhancement of the heat transfer can be achieved by the variation of the design factor like the sealing strip located on the top/bottom and middle of the baffle.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2002년도 추계 학술대회논문집
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• pp.71-77
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• 2002

The grid technology is believed to be the next generation research tool for both computational and experimental scientists. With advanced network technologies and middleware, geographically distributed facilities can be tightly connected to provided a huge amount of resources or remote accessibility, In this paper, an overview of grid technology will be introduced with an emphasis in application to computational fluid dynamics. The computational fluid dynamics, which involves solution of partial differential equations, is basically limited by the computing power, With the grid technology, virtually unlimited resources are provided. The schematic structure of middleware and grid environment, as well as some preliminary results are presented.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2002년도 추계 학술대회논문집
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• pp.114-119
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• 2002

A numerical model is employed for design of a spinner device to dry the 5-th generation LCD glass panel. The turbulent flow in a spinner is driven by rotation of a large disk and suction by the exhaust system connected to vacuum chamber, which is simulated by using the FLUENT package. Based on numerical simulation, the required capacity of exhaust system is assessed. The effects of the presence of cover on the flow characteristics are examined. A computational trouble shooting is attempted to resolve the problem of panel rising which occurred in real experiments.

• 한국전산유체공학회지
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• 제16권3호
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• pp.15-21
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• 2011

Aerothermodynamic flowfields of aircraft engine nozzles are computationally investigated at various flight conditions for infrared signature analysis. A mission profile of subsonic unmanned combat aerial vehicle is considered for the case study and associated engine and nozzles are selected through a performance analysis. Computational results of nozzle and plume flowfields using a density-based CFD code are analyzed in terms of thrust, maximum temperature, length and optical thickness of plume. It is shown that maximum temperature, length, and optical thickness of nozzle plume increase for lower altitude and higher Mach number.

• 한국전산유체공학회지
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• 제16권3호
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• pp.82-87
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• 2011

The battery pack, a main component of NEV(Neighborhood Electric Vehicle), needs cooling system when it is charging or discharging to prevent the degradation of the battery charging efficiency. The purpose of this study is to analyse the effects of cooling methods, changing positions of inlet and outlet and changing area ratios of inlet and outlet. It has been observed that in the point of uniform cooling, suction from the exit side is more efficient than blowing from the inlet. And there is a suitable inlet/outlet area ratio in maximizing the mass flow rate. A commercial code, STAR-CCM+(ver. 4.02), was used for the numerical study.

• 한국전산유체공학회지
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• 제12권1호
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• pp.22-27
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• 2007

Automobile underhood thermal and airflow simulation h α s been performed by using a commercial CFD program, FLUENT. To implement the radiation heat transfer effect to the underhood thermal and flow field, Discrete Ordinates Method(DOM) was used. The cooling fan was modeled by using the Multiple Reference Frame(MRF) technique. For the implementation of the heat exchangers, such as radiator and condenser, which are located in the front side of vehicle, the effectiveness-NTU model was used. The pressure drop throughout the heat exchangers was modeled as Porous media. For the validation of the current computational method, the coolant temperature at the inlet port of the radiator was compared with experimental data, and less than 3% error was observed. Finally, the composed model was used for the cooling fan spec determination process in the development of a new vehicle, and the results showed that the current CFD method could be successfully applied to the vehicle development process.

• 한국전산유체공학회지
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• 제17권2호
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• pp.11-20
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• 2012

In this paper, the authors test various open codes and commercial codes based on CFD technology on the wind field around the complex terrain, which is a very important transport physics in the event of forrest fire. To study the physical mechanism inside the transition from surface fire to crown fire, the wake flow behind a parallel array of trees is studied numerically to show the flow separation in the turbulent boundary layer. Two sites near to Kunsan National University are chosen for the measurement of real wind field, and obtained data are compared with those from various computational codes such as Wind-Ninja, NIST-FDS, ANSYS-CFX, and ANSYS-FlUENT, etc. Through this research, feasibility and accuracy of the present CFD codes are investigated quantitatively, compared with the measured data with AWS.

• 한국전산유체공학회지
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• 제16권3호
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• pp.95-103
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• 2011

In the block type VHTR core, there are inevitable gaps among core blocks for the installation and refueling of the fuel blocks. These gaps are called bypass gap and the bypass flow is defined as a coolant flows through the bypass gap. Distribution of core bypass flow varies according to the reactor operation since the graphite core blocks are deformed by the fast neutron irradiation and thermal expansion. Furthermore, the cross-flow through an interfacial gap between the stacked blocks causes flow mixing between the coolant holes and bypass gap, so that complicated flow distribution occurs in the core. Since the bypass flow affects core thermal margin and reactor efficiency, accurate prediction and evaluation of the core bypass flow are very important. In this regard, experimental and computational studies were carried out to evaluate the core bypass flow distribution. A multi-block experimental apparatus was constructed to measure flow and pressure distribution. Multi-block effect such as cross flow phenomenon was investigated in the experiment. The experimental data were used to validate a CFD model foranalysis of bypass flow characteristics in detail.

• 한국전산유체공학회지
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• 제14권2호
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• pp.59-67
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• 2009

An accurate prediction of the bypass flow is of great importance in the VHTR core design concerning the fuel thermal margin. Nevertheless, there has not been much effort in evaluating the amount and the distribution of the core bypass flow. In order to evaluate the behavior and the distribution of the coolant flow, a unit-cell experiment was carried out. Unit-cell is the regular triangular section which is formed by connecting the centers of three hexagonal blocks. Various conditions such as the inlet mass flow rate, block combinations and the size of bypass gap were examined in the experiment. CFD analysis was carried out to analyze detailed characteristics of the flow distribution. Commercial CFD code FLUENT 6.3 was validated by comparing with the experimental results. In addition, SST model and standard k-$\varepsilon$ model were validated. The results of CFD simulation show good agreements with the experimental results. SST model shows better agreement than standard k-$\varepsilon$ model. Results showed that block combinations and the size of the bypass gap have an influence on the bypass flow ratio but the inlet mass flow rate does not.