• Proceedings of the KSME Conference
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• 2001.06e
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• pp.162-168
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• 2001

In the present study, flow visualizations, hot-wire velocity measurements and computational fluid dynamics were performed in order to determine complicated air flow characteristics in a neonate incubator. In this study, following conclusions can be made: (1) The flow visualization technique developed in the present study revealed an enough qualitative information for the flow field in the neonate incubator. Flow structures in a neonate incubator with a realistic three-dimensional shape was successfully visualized the present study. (2) Results from the flow visualization were relatively in good agreements with those obtained from the computational fluid dynamics. (3) Velocities very near the neonate measured by the hot-wire anemometer were relevant to those obtained from the computational fluid dynamics. (4) Temperatures were higher at the neck region and the medial aspect of both thighs, but lower in both extremities. (5) Small vortices between the neonate and the mattress might interfere with convective and evaporative heat transfers on the neonate's surface. In the fluid dynamic aspect, it is important to eliminate the formation of these small vortices for the design of incubator chamber.

• 한국전산유체공학회:학술대회논문집
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• 2008.08a
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• pp.67.1-67.1
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• 2008

• 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.

• 한국전산유체공학회:학술대회논문집
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• 2008.08a
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• pp.34.3-34.3
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• 2008

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.256-259
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• 2003

Artificial heart is divided pulsation style and nonpulsation style greatly according to flowing of blood. nonpulsation pump is advantage of miniaturization avaliable because it is simple and non-volumic-pump than pulsation pump. Non pulsation pump is derided axial flow style and centrifugal style accordig to rotating style. An axial flow blood pump can be made smaller than a centrifugal blood pump because of its higher specific speed. A hemolysis is an important factor for the development of an axial flow blood pump. It is difficult to identify the areas where hemolysis nun. Evaluation of hemolysis both in in vitro and in vivo require a long time and are costly. Computational fluid dynamics(CFD) analysis enables the engineer to predict hemolysis on a computer. The aims of this study is Computational fluid dynamics in the whole axial flow pump and to verify the accuracy of prediction results of CFD analysis compare with in vitro experimental results.

• International Journal of Vascular Biomedical Engineering
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• v.1 no.2
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• pp.36-41
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• 2003

Both flow visualizations and computational fluid dynamics were performed to determine hemodynamics in a total cavopulmonary connection (TCPC) model for surgically correcting congenital heart defects. From magnetic resonance images, an anatomically correct glass model was fabricated to visualize steady flow. The total flow rates were 4, 6 and 8L/min and flow rates from SVC and IVC were 40:60. The flow split ratio between LPA and RPA was varied by 70:30, 60:40 and 50:50. A pressure-based finite-volume software was used to solve steady flow dynamics in TCPC models. Results showed that superior vena cava(SVC) and inferior vena cava(IVC) flow merged directly to the intra-atrial conduit, creating two large vortices. Significant swirl motions were observed in the intra-atrial conduit and pulmonary arteries. Flow collision or swirling flow resulted in energy loss in TCPC models. In addition, a large intra-atrial channel or a sharp bend in TCPC geometries could influence on energy losses. Energy conservation was efficient when flow rates in pulmonary branches were balanced. In order to increase energy efficiency in Fontan operations, it is necessary to remove a flow collision in the intra-atrial channel and a sharp bend in the pulmonary bifurcation.

• Korea-Australia Rheology Journal
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• v.20 no.2
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• pp.89-94
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• 2008

To satisfy good mechanical and optical properties of polymer-coated film products, it will be indispensable to elucidate the molecular orientation of polymer chains within coating liquids in coating flows. Using hybridized numerical method between computational fluid dynamics (CFD) and Brownian dynamics (BD) simulations can provide the useful information for the better quality control of coated films. Flexible polymer chains, e.g., ${\lambda}$-DNA molecules here, change their conformation according to the flow strength and the flow type. The molecular conformation within the coated film on the web or substrate is quite different, because the polymer chains experience the complicated flow strength and flow types in flow field. Especially in the slot coating flow, these chains are more extended by the extension-like flow field generated in the free surface curvature just beyond the downstream die region. Also, the polymer chain extension beneath the free surface can be affected by the die geometry, e.g., the coating gap, changing flow field.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.9 s.240
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• pp.1042-1048
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• 2005

Numerical investigation has been made on the stent design to minimize the neointimal hyperplasia. Computational fluid dynamics is applied to investigate the flow distributions in the immediate vicinity of the given idealized stent implanted in the blood vessel. Parametric study on the variations of the number of stouts, stent diameters, stent spacings and Reynolds numbers has been conducted using axi-symmetric Navier-Stokes equations. An initial difficulty in the study is to determine the optimal stent design to understand the flow physics of the flow disturbance induced by stent. The size of recirculation zone around stent is depend on the stent diameter, number of stent wire and Reynolds number but is insensitive to the stent wire spacing. It is also found that when the flow is in acceleration, the flow sees a more favorable pressure gradient, and the separation zones are smaller than the steady flow case. When the flow is in deceleration and the flow sees a more adverse pressure gradient so that the separation zones are larger.

• 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.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.28-33
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• 2023

In this study, computational fluid dynamics was used to analyze the flow bias generated as air supplied by a fan passes through ducts, piping, and a coal separation screen. The flow bias of the air flow is mostly caused by the spatial characteristics of the fan volute and duct, and the internal baffle and the coal separation screen at the outlet cause strong pressure losses that dampen the flow bias. ANSYS CFX was used for computational fluid dynamics, and since the baffle and the coal separation screen are shaped like perforated plates with many small holes uniformly distributed, actual modeling for analysis was not possible. Therefore, the Porous Loss Model was applied. The evaluation of the flow bias was analyzed based on the velocity distribution of the Porous Loss Model at the outlet surface of the coal separation screen obtained from the computational fluid dynamics results.