• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.606-609
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• 2009

Development of renewable energy is very important because of environmental problems caused by greenhouse effect. This is due to the use of fossil fuels which has serious consequences. Therefore, development of small hydropower can be a good countermeasure for the problems. The small hydropower is clean energy because the small hydropower generates few $CO_2$. Moreover, as the energy density by the small hydropower is high, it is economical for a society which wants to introduce the system. The purpose of this study is to improve the turbine performance. This study is about tubular-type hydro turbine among renewable energy that is based using the different water pressure level in pipe lines. The analysis was performed using the commercial CFD code ANSYS-CFX.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.5
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• pp.63-69
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• 2004

This study contains the CFD analysis to predict the flow in engine room and utilize the results as a reference for arranging smoke detectors. FLUENT, a commercial CFD code is adopted because of its good application experience in DSME(Daewoo Shipbuilding & Marine Engineering Co.. Ltd.). The target is the engine room of VLCC. which was delivered in 2002. The model for analysis includes main structure elements, ventilation ducts, main engine and other big size equipment. From the analysis results, the internal flow pattern can be observed and some guidelines for the position of smoke detectors cane be presented.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.1
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• pp.86-91
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• 2013

It is important to understand the fuel injection characteristics, particularly the atomization, penetration, and breakup, for reducing the emissions in Diesel engines because those characteristics are related to the formation of the emissions. 3-dimensional CFD code can provide a fundamental understanding of those characteristics. In this study, two different breakup models (the Reitz-Diwakar model and the Kelvin-Helmholts Rayleigh Taylor model) were validated with the experimental data in a constant volume vessel. Then, the effect of the breakup model on the characteristics of the engine combustion and emission was studied.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.456-461
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• 2004

In this study, the characteristics of the cavitation behavior around hydrofoil are investigated with the commercial CFD code CFX-5. Calculations are performed for NACA 64108 hydrofoil by solving the time-averaged turbulent Navier-Stokes equations and discretized by finite volume method. We classify the different cavitating regimes in which appear at the hydrofoil according to the values of cavitation number, surface roughness and angle of attack. Special attention is paid to the following topics: cavity length, void fraction and lift breakdown.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.5
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• pp.795-804
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• 2015

Tip clearance loss is a limitation of the improvement of turbomachine performance. Previous studies show the Tip clearance loss is generated by the leakage flow through the tip clearance, and is roughly linearly proportional to the gap size. This study investigates the tip clearance effects on the performance of ducted propeller. The investigation was carried out by solving the Navier-Stokes equations with the commercial Computational Fluid Dynamic (CFD) code CFX14.5. These simulations were carried out to determine the underlying mechanisms of the tip clearance effects. The calculations were performed at three different chosen advance ratios. Simulation results showed that the tip loss slope was not linearly at high advance due to the reversed pressure at the leading edge. Three type of vortical structures were observed in the tip clearance at different clearance size.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.558-563
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• 2005

In this paper, the effect of volute area distribution on the performance characteristic curve of a centrifugal pump were numerically studied using a commercial CFD code. To reduce the shutoff head, maintaining head and efficiency at a design flow rate, the flat head-capacity characteristic curves in which the head varies only slightly with capacity from shutoff to design capacity are frequency required. In order to control the shutoff head of a pump, several volute area distributions were proposed as a main parameter with the same impeller geometry. The calculation results show that the characteristic curve of a centrifugal pump can be controlled by modifying the area distribution with the same volute outlet area.

• The KSFM Journal of Fluid Machinery
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• v.15 no.5
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• pp.54-59
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• 2012

In order to have the high efficiency of aircraft wing and to improve the energy efficiency in field of eco-friendly transportation, the performance characteristics of the aircraft wing were studied with the change of lift to drag ratio through the CFD analysis. The design process was focused on generating the high lift force and low drag force as the lift to drag ratio was increased. In this paper, various dimple patterns were numerically designed to investigate the flow characteristics. Hexagon-and circle-shaped dimples, dimple distance and position were changed as the artificial conditions. The numerical analyses were conducted by using the commercial code, ANSYS CFX. Numerical results dependent on the turbulence intensity and lift to drag ratio distribution were graphically depicted for various dimple patterns.

• Journal of Drive and Control
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• v.9 no.4
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• pp.26-31
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• 2012

Friction reduction between sliding hydraulic machine components is required to improve efficiency and reliability of hydraulic machineries. It is recently reported that surface texturing on sliding bearing surfaces can reduce the friction force highly. In this paper, numerical analysis is carried out to investigate the effect of dimple numbers and inlet boundary pressures on the lubrication characteristics of a parallel sliding bearing using a commercial computational fluid dynamics (CFD) code, FLUENT. The results show that the pressure distribution, load capacity, dimensionless friction force and leakage with dimple number and their locations, and inlet pressures. The overall lubrication characteristics are highly affected by dimple numbers and boundary pressure. The numerical method adopted and results can be used in design of efficient hydraulic machine components.

• The KSFM Journal of Fluid Machinery
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• v.9 no.4 s.37
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• pp.43-48
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• 2006

In this study, the effect of flow settling means on the performance of fan tester were numerically investigated by using a computational fluid dynamics(CFD). The airflow rate was calculated from the pressure differential across a flow nozzle in the measuring plane and the flow settling means were generally installed in the chamber of the fan tester to provide proper airflow patterns ahead of the measuring plane. The predicted nozzle differential pressures with uniform inlet velocities were compared with the values of the ANSI/AMCA 210-99 to verify the performance of the commercial CFD code CFX 5.6. The influence of flow settling means on the measurement of airflow rate in a fan tester were discussed with various porosities and inlet jet velocities. The results obtained show that the proper band of porosities exist to meet the AMCA standard in a specified inlet jet velocity.

• Journal of computational fluids engineering
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• v.12 no.4
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• pp.85-89
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• 2007

In the present work, flow analysis has been performed for side channel type double stage ring blower by solving three-dimensional Reynolds-averaged Navier-Stokes equation. Shear stress transport model is used as turbulent closure. The commercial CFD code CFX 11.0 is used for the calculations. Each of two stage is calculated separately and the second stage inlet flow is same as the first stage outlet flow so that consecutive calculation is possible. Velocity and pressure fields have been analyzed at the mid-plane between blades. The numerical results are validated with experimental data for head coefficients at different flow coefficients.