• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.572-575
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• 2008

Flow-field design has much influence over the performance of proton exchange membrane fuel cell (PEMFC) because it affects the pressure magnitude and distribution of the reactant gases. To obtain the pressure magnitude and distribution of reactant gases in four kinds of flow-field designs without additional measurement equipment, computational fluid dynamics (CFD) analysis was performed. After the CFD analysis, the performance values of PEMFC according to the flow-field configurations were measured via a single cell test. As expected, the pressure differences due to different flow-field configurations were related to the PEMFC performance because the actual performance results showed the same tendency as the results of the CFD analysis. A large pressure drop resulted in high PEMFC performance. So, the single serpentine configuration gave the highest performance. On the other hand, the parallel flow-field configuration gave the lowest performance because the pressure difference between inlet and outlet was the lowest.

• Membrane and Water Treatment
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• v.7 no.2
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• pp.115-126
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• 2016

In this study, computational fluid dynamics (CFD) analysis was conducted to investigate the flow pattern and to find the occurrence of dead zones in an existing capacitive deionization (CDI) cell. Newly designed cells-specifically designed to avoid dead zones-were analyzed by CFD in accordance with the flow rates of 15, 25 and 35 ml/min. Next, the separation performances between the existing and newly designed cell were compared by conducting CDI experiments in terms of salt removal efficiency at the same flow rates. Then, the computational and experimental results were compared to each other. The salt removal efficiencies of the hexagon flow channel 1 (HFC1) and hexagon flow channel 2 (HFC2) were increased 88-124% at 15 ml/min and 49-50% at 25 ml/min, respectively. There was no difference between the existing cell and the foursquare flow cell (FFC) at 35 ml/min.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.517-523
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• 2010

Recently, the rapid evolution of computational fluid dynamics (CFD) has enabled its key role in industries and predictive sciences. From diverse research disciplines, however, are there strong needs for integrated analytical tools for multi-phenomena beyond simple flow simulation. Based on the concurrent simulation of multi-dynamics, multi-phenomena beyond simple flow simulation. Based on the concurrent simulation of multi-dynamics, multi-physics and multi-scale phenomena, the multi-phenomena CFD technology enables us to perform the flow simulation for integrated and complex systems. From the multi-phenomena CFD analysis, the high-precision analytical and predictive capacity can enhance the fast development of industrial technologies. It is also expected to further enhance the applicability of the simulation technique to medical and bio technology, new and renewable energy, nanotechnology, and scientific computing, among others.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.1
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• pp.10-20
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• 2017

This study presents the feasibility of CFD(computational fluid dynamic) analysis using the flow angularity wind tunnel test technique. The CFD analyzed data by the flow angularity technique has been constructed as the database to get store trajectories by 6-DOF simulation. The database has been checked out store aerodynamic coefficients by the analyses at each position under wing. After that process, the simulated trajectories by database have been compared with the store trajectories by CTS(Captive Trajectory Simulation) of CFD. The trajectories provided by the database of flow angularity have a good agreement with the store trajectories by CFD.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1687-1697
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• 2024

This study presents the Supporting platform for reactor fine flow characteristics calculation and analysis (Cilian platform), a user-friendly tool that supports the analysis and optimization of pressurized water reactor (PWR) cores with mixing vanes using computational fluid dynamics (CFD) computing. The Cilian platform allows for easy creation and optimization of PWR's main CFD calculation schemes and autonomously manages CFD calculation and analysis of PWR cores, reducing the need for human and computational resources. The platform's key features enable efficient simulation, rapid solution design, automatic calculation of core scheme options, and streamlined data extraction and processing techniques. The Cilian platform's capability to call external CFD software reduces the development time and cost while improving the accuracy and reliability of the results. In conclusion, the Cilian platform exemplifies an innovative solution for efficient computational fluid dynamics analysis of pressurized water reactor (PWR) cores. It holds great promise for driving advancements in nuclear power technology, enhancing the safety, efficiency, and cost-effectiveness of nuclear reactors. The platform adopts a modular design methodology, enabling the swift and accurate computation and analysis of diverse flow regions within core components. This design approach facilitates the seamless integration of multiple computational modules across various reactor types, providing a high degree of flexibility and reusability.

• Transactions of The Korea Fluid Power Systems Society
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• v.5 no.1
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• pp.20-26
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• 2008

Various types of hydraulic shock absorbers are widely used in many fields because of its numerous advantages. However, in order to design adequate damping characteristics, accurate flow data near the orifices are required essentially. In this paper, a commercial computational fluid dynamics(CFD) code, FLUENT is adopted to investigate the flow characteristics near orifices of a shock absorber. Static pressure and velocity vector distributions, fluid path lines are presented for compression/tension strokes and various piston speeds. In order to validate the result of analysis, the numerically obtained damping forces are compared with those of analytical estimations obtained by modified Bernoulli equation. The results reported herein will provide better understanding of the detailed flow fields within shock absorber, and the CFD analysis method proposed in this paper can be used in the design of other types of hydraulic shock absorber.

• Journal of computational fluids engineering
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• v.15 no.4
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• pp.109-114
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• 2010

In a fan design, CFD analysis, which is very useful for mechanical design relating to the heat and fluid dynamics, is one of the most popular tools. However, since the CFD analysis is conventionally carried out with the constant fan speed condition, the speed change, induced by the air flow rate and motor characteristics, is hardly modeled. And, consequently, the remarkable difference exist between analysis and experimental results. In this paper, we has proposed a method of setting the varying fan speed as a boundary condition considering air flow rate and motor torque-speed characteristics. The effectiveness of the proposed method is verified by comparison with experimental results.

• Journal of the Korean Society for Heat Treatment
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• v.35 no.1
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• pp.27-32
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• 2022

Microbubble technology has been widely applied in various industrial fields. Recently, research on many types of microbubble application technology has been conducted experimentally, but there is a limit in deriving the optimal design and operating conditions. Therefore, if the computational fluid dynamics (CFD) analysis of multiphase flow is used to supplement these experimental studies, it is expected that the time and cost required for prototype production and evaluation tests will be minimized and optimal results will be derived. However, few studies have been conducted on multiphase flow CFD analysis to interpret fluid flow in microbubble generators using swirl flow. In this study, CFD simulation of multiphase flow was performed to analyze the air-water mixing process and fluid flow characteristics in a microbubble generator with a dual-chamber structure. Based on the simulation results, it was confirmed that a negative pressure was formed on the central axis of rotation due to the strong swirling flow. And it could be seen that the air inside the suction tube was introduced into the inner chamber of the microbubble generator. In addition, as the high-speed mixed fluid collided with external water sucked by the negative pressure near the outlet, a large amount of microbubbles was ejected due to the shear force between the two flows flowing in opposite directions.

• Nuclear Engineering and Technology
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• v.33 no.3
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• pp.327-338
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• 2001

A computational fluid dynamics (CFD) analysis was performed to propose the optimum design of flow mixing vane on the space grid in a PWR fuel assembly. The flow mixing vanes considered in this study for optimum design are swirl-vane and twisted-vane. A single subchannel of one grid span was modeled using flow symmetry to minimize the computational effort. The CFD predictions are in good agreement with the experimental results for the split- vane, which shows the applicability of the CFD method. The mixing effect by swirling flow and crossflow, and the pressure drop were estimated and compared for the various vane angles. The optimum vane angle is proposed to be 40。 and 35。 from the direction of axial flow for the swirl-vane and the twisted-vane, respectively.

• Journal of the Korean Society of Tobacco Science
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• v.32 no.2
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• pp.63-69
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• 2010

In the chemical, mineral and electronics, mechanically stirred tanks are widely used for complex liquid mixing processes. The paper present results from a computational fluid dynamics (CFD) model for the mixing tank in casing process. We used CFD software, FLUENT(Fluent, Inc, Lebanon, NH, version 6.2). A species transport model was used to model the problem. The flow patterns in a mixing tank, 1.6 m in diameter and 2.0 m in height, were studied using CFD. Numerical analysis results show that improved mixing tank was reduced low speed flow region and turbulent region in internal flow of mixing tank.