• The KSFM Journal of Fluid Machinery
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• v.17 no.5
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• pp.72-77
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• 2014

Because of overload working condition of sintering cooler, the cooler fan often suffers the break or damage of rotor blade and fixing shaft. Therefore, internal flow characteristics of a steelworks sintering cooler fan by the duct shape of the cooler fan outlet, such as duct outlet opening ratio, duct height and dividing wall shape on the duct outlet flow pattern are examined in detail. The results show that relatively short duct wall height and attachment of dividing wall shape improves flow patterns considerably.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.702-707
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• 2001

The characteristics of flow in dividing regions are precise, therefore their classification is very important not only in industry but also in hydrodynamics. By now, many studies of flow in dividing regions have been performed, but flow characteristics that use visualization in dividing regions have not been studied. The present study of the PIV and the CFD exhibit average velocity distributions, kinetic energy distributions and total pressure distributions etc of the total flow field due to the development of the accurate visualization optical laser and of optical equipment. Also, PIV is accurate with the flows characteristics of the dividing region as continuous analysis is done using input equipment. The study analyzes average velocity vector field, average kinetic energy, x-axis stress distributions, average and total pressure distributions of dividing regions with flow for visualization of the PIV and the CFD measurement in a dividing rectangular duct.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.35-39
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• 2002

The flow characteristics in a bifurcated duct are investigated experimentally. Physical properties such as mean velocity vectors, mean vorticity and total pressure distributions are obtained for three different Reynolds numbers(578, 620, 688) using PIV measurements and CFD analysis. Also, dividing duct $90^{\circ}$ were selected for study. The results of this study would be useful to the engineer in designing the flow systems for heating, ventilation, air conditioning and wastewater purification plants.

• The KSFM Journal of Fluid Machinery
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• v.5 no.4 s.17
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• pp.19-25
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• 2002

The flow characteristics in a bifurcated duct are investigated experimentally. Physical properties such as mean velocity vectors, mean vorticity, and total pressure distributions are obtained for three different Reynolds numbers (578, 620, 688) using PIV measurements and CFD analysis. Also, two different dividing ducts ($90^{\circ},\;60^{\circ}$) were selected for study. The results of this study would be useful to the engineers designing flow systems for heating, ventilation, air conditioning and waste-water purification plants.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1195-1202
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• 2001

The flow characteristics in a bifurcated duct are investigated experimentally. Physical properties such as mean velocity vectors, mean x-y stress distributions, mean vorticity and total pressure distributions are Obtained for three different Reynolds numbers(578, 620, 688) Using PIV measurements and CFD analysis. Also, three different rates of discharge Q=26.11 l/min, Q=28.11 $\ell$/min, Q=31.17 $\ell$/min) were selected foy experimental conditions. The results of this study would be useful to the engineer in designing the flow systems for heating, ventilation, air conditioning and wastewater purification plants.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.5 s.236
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• pp.545-553
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• 2005

In the present study, The characteristics of developing steady laminar flows of a straight duct connected to a $180^{\circ}$ curved duct were examined In the entrance region through experimental measurement. Flow characteristics such as shear stress distributions, pressure distributions and friction coefficient experimentally in a square cross-sectional straight duct by using the PIV system. For the PIV measurement by particles produced from mosquito coils particles. The experimental data were obtained at 9 points dividing the test sections by 400mm. Experimental results can be summarized as follows. Critical Reynolds number, $Re_{cr}$ which indicates transition from laminar steady flow to transition steady flow was 2,150. Shear stress per unit length on the wall was stronger than that in the fully developed flow region. This was attributed to the fact that shear stress and pressure loss in the curvature of a duct were increased. Pressure distributions were gradually decreased irrespective of Reynolds number In the whole test section. This trends were in a good agreement with the reference results. Pipe friction coefficient in the steady state flow region was calculate from method of least squares. The co-relationship between fiction coefficient and Reynolds number was established as follow; ${\lambda}=56/Re$.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.9
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• pp.1058-1065
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• 2004

In the present study, characteristics of steady state laminar flows of a straight duct connected to a 180$^{\circ}$ curved duct were examined in the entrance region through experimental and numerical analyses. For the analysis, the governing equations of laminar flows in the Cartesian coordinate system were applied. Flow characteristics such as velocity profiles, and secondary flows were investigated numerically and experimentally in a square cross-sectional straight duct by the PIV system and a CFD code(STAR CD). For the PIV measurement, working fluid produced from mosquito coils smoke. The experimental data were obtained at 9 points dividing the test sections by 400 mm. Experimental and numerical results can be summarized as follows. Critical Reynolds number, Recr which indicates transition from laminar steady flow to transition steady flow was 2,150. As Reynolds number, Re, was increased, dimensionless velocity profiles at the outer wall were increased due to the effect of the centrifugal force and the secondary flows. The intensity of a secondary flow became stronger at the inner wall rather than the outer wall regardless of Reynolds number.

• 한국전산유체공학회:학술대회논문집
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• 2003.08a
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• pp.200-205
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• 2003

The Canard rotor/wing (CRW) aircraft concepts offer great potential for application by allowing the use of a common propulsion system for high-speed cruise and low-speed powered lift. Using the rotor for lift in both flight modes increases its utility. In the hovering mode, the exhausted gas from an gas turbine engine is accelerated through the duct system and it provides the tipjet power for rotor system enough to lift the aircraft. In the cruise mode, the rotor is fixed and the exhausted gas is extracted through the main nozzle, such that the aircraft is able to flight with high speed. The duct system was designed using 1-D fanno line flow theory and empirical data. However, the empirical data of the pressure loss coefficient for various bending and dividing ducts were not enough to design our duct system adaptively. Therefore, using 3-D CFD analysis we obtained the pressure loss coefficient for our duct models and chose the appropriate bending or diving duct type. In this paper, we used the CFD-ACE+ software package for the CFD analysis and the modeling of duct system. Through the 3-D CFD analysis, we investigated also the pressure loss and the velocity distributions of the designed whole duct system as well as the blade duct. Comparing the 3-D CFD result with 1-D analysis result, we lessened the uncertainty of the designed duct system and speculated the problem that was not concerned in design state.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.10 s.241
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• pp.1092-1100
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• 2005

In the present study, characteristics of steady state laminar flows of a straight duct connected to a 180$^{o}$ curved duct were examined in the entrance region through experimental and numerical analyses. For the analysis, the governing equations of laminar flows in the Cartesian coordinate system were applied. Flow characteristics such as velocity profiles and secondary flows were investigated numerically and experimentally in a square cross-sectional straight duct by the PIV system and a CFD code(STAR CD). For the PIV measurement, smoke particles produced from mosquito coils. The experimental data were obtained at 9 points dividing the test sections by 400 3m. Experimental and numerical results can be summarized as follows. 1) Reynolds number, Re was increased, dimensionless velocity profiles at the outer wall were increased due to the effect of the centrifugal force and secondary flows. 2) The intensity of a secondary flow became stronger at the inner wall rather than the outer wall regardless of Reynolds number. Especially, fluid dynamic phenomenon called conner impact were observed at dimensionless axial position, x/D$_{h}$=50.

• Journal of computational fluids engineering
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• v.20 no.2
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• pp.1-6
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• 2015

In this study, a numerical prediction on propulsive performance of a ducted propeller in open water condition was carried out by solving Reynolds averaged Navier-Stokes(RANS) equation using computational fluid dynamics(CFD). A configuration of propeller Ka-470 inside duct 19A was considered. Hexahedral grid system was generated by dividing whole computational domain into three separate regions; propeller, duct and outer flow region. A commercial CFD software, ANSYS-CFX was used for numerical simulations. Results were compared with experimental data and showed considerable improvement in accuracy, in comparison to those from surface panel method which is based on potential flow assumption. The results also exhibited the importance of grid system within the gap between the inner surface of duct and blade tip for accurate prediction of propulsive performance of ducted propeller.