• Journal of the Korea Convergence Society
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• v.5 no.2
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• pp.19-23
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• 2014

In this study, the air resistance is studied by using flow analysis near automotive body due to the its shape. Flow velocities of airs entering into inlet plane are two kinds of 70 km/h and 100 km/h. Air resistance in case of high speed driving(100 km/h) becomes higher than regular speed driving(70 km/h) and the resistance in case of the car with wider cross section at front side becomes higher than narrower cross section. By using this analysis result, the shape of automotive body can be effectively designed in order to reduce the air resistance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.7
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• pp.877-884
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• 2004

In this paper, structural analysis is performed to investigate the deformation of porous media in a proton exchange membrane fuel cell (PEMFC). Structural deformation of air plate of the fuel cell causes the change in configuration and cross sectional area of the channel. The distributions of mass flow rate and pressure are major factors to decide the performance of a PEMFC. These factors are affected by channel configuration of air plate. Two kinds of numerical air plate models are suggested for flow analyses. Deformed porous media and undeformed porous media are considered for the two models. The Numerical flow analysis results between deformed porous media and undeformed porous media have some discrepancy in pressure distribution. The pressure and velocity distribution under a working condition are numerically calculated to predict the performance of the air plates. Pressure and velocity distributions are compared for two models. It is shown that structural deformation makes difference in flow analysis results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.461-462
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• 2009

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.3
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• pp.8-17
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• 2015

In this research, low fidelity air/heat load analysis was conducted for the intake of high speed vehicle. For air/heat load calculations, aerodynamic properties at the surface and the boundary layer edge were estimated using Taylor-Maccoll equation for conical flow, shockwave relation and Prandtl-Meyer expansion equation for internal and external flow. Couette flow assumption and Reynolds analogy were used in order to calculate convective heat transfer coefficient. In order to calculate skin friction coefficient for heat transfer coefficient analysis, Van Driest method II and Reference Enthalpy method were considered. An axis symmetric SCRAMJET model was selected as a reference configuration for verifying the proper implementation of the present method. Comparison of the results using the present method and Computational Fluid Dynamic analysis showed that the present method is valuable for efficiently providing pressure and heat loads for air-intake structure design of the high speed air vehicle.

• Journal of the Korea Convergence Society
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• v.11 no.5
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• pp.159-164
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• 2020

In this study, the flow analysis of air in the inner side of vehicle due to the position on inlet port of air at car was carried out. Under the comfortable condition as the inlet port in which the air flows, it was possible to confirm that the inlets became the upper and middle sides or the forward side of the vehicle. If the air flow is not evenly distributed within the vehicle, the lower position of the vehicle is the lowest condition among all conditions. The results of this study will help to keep the inner state of the vehicle pleasant by adjusting the location of the inlet to suit the passenger's taste or situation. The design and analysis results of this study can be effectively applied at adjusting the location of the inlet at car. By applying the flow analysis according to the inlet port of air at car, this paper is seen as the convergence study that conforms to aesthetic design.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.2
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• pp.252-258
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• 1999

As an effective means to convey crushed materials from seabed to on board ship and to raise hazardous or abrasive liquids air-lift pump provides a reliable mechanism due to its simple config-uration and easy-to-operate principle. The present study is focused on fundamental investigation of related performance by the analysis program based on the gas-liquid two-phase flow in circular pipes. The program covers pump operating in isothermal and vertical two-phase flow with Newto-nian liquids. it is summarized as important result that an optimum air mass flow rate exists for the maximum lifted liquid mass flow rate in terms of a given submergence rates and furthermore attachment of downcomer gives little effects on riser performance the conveyed liquid flow rate increases with larger submergence rate.

• Journal of the Korean Society of Visualization
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• v.9 no.4
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• pp.47-53
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• 2011

A water driven ejector loop was designed and constructed for air absorption. The used ejector was horizontally installed in the loop and annular water jet at the throat entrained air through the circular pipe placed at the center of the ejector. Wide range of water flow rate was provided using two kinds of pumps in the loop. The tested range of water flow rate was 100${\ell}$ /min to 1,000 ${\ell}$/min. Two-phase flow inside the ejector loop was simulated by CFD analysis. Homogeneous particle model was used for void fraction prediction. Water and air flow rates and pressure drop through the ejector were automatically recorded by using the LabView based data acquisition system. Flow characteristics and air bubble velocity field downstream of the ejector were investigated by two-phase flow visualization and PIV measurement based on bubble shadow images. Overall performance of the two-phase ejector predicted by the CFD simulation agrees well with that of the experiment.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.572-577
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• 2006

Numerical simulation has been made on the performance of an oil free air compressor for automotive electronic air suspension system. Calculation results on the flow rate at various air supply pressures were reasonably well compared to the experimental data. With the aid of the computer simulation program, parametric study on the compressor design parameters has also been carried out for the compressor performance improvement: Increase in the discharge port diameter or discharge valve stiffness was found to be effective to increase the flow rate per unit compressor input for the present compressor model.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.515-516
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• 2008

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.9 s.180
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• pp.2159-2166
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• 2000

Recently, high performance machining center requires special type of sealing mechanism that prevent a leakage of oil jet or oil mist lubrication system. Sealing of oil-air mixture plays important r oles to have an enhanced lubrication for performance machining center. Current work emphasizes on investigations of the air jet effect on the protective collar type labyrinth seal. To improve sealing capabilities of conventional labyrinth seals, air jet is injected against the leakage flow. In this study, an adapted model is introduced to improve sealing capability of conventional non-contact type seals. It has a combined geometry of a protective collar type and an air jet type. Both of a numerical analysis by CFD (Computational Fluid Dynamics) and experimental measurements are carried out to verify sealing improvement. The sealing effects of the leakage clearance and the air jet magnitude aic studied in various parameters. Gas or liquid has been used as a working fluid for most of nori-contact types seals including the labyrinth seal. However, it is more reasonable to regard two-phase flows because oil mist or oil jet are used for high performance spindle's lubrication. In this study, working fluid is regarded as two phases that are mixed flow of oil and air phase. Both of turbulence and compressible flow model are also introduced in a CFD analysis to represent an isentropic process. Estimation of non-leaking property is determined by amount of pressure drop in the leakage path. Results of pressure drop in the experiment match reasonably to those of the simulation by introducing a flow coefficient. Effect of the sealing improvement is explained as decreasing of leakage clearance by air jetting. Thus, sealing effect is improved by amount of air jetting even though clearance becomes larger