• Title/Summary/Keyword: Darcy′s law

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A Study on the Coating Thickness Prediction of a Piston Skirt (피스톤 스커트의 코팅두께 예측에 관한 연구)

  • Chun, Sang-Myung
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.2
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    • pp.84-91
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    • 2011
  • The purpose of this study is to find how to be formed the wet film thickness during the low friction coating process for a piston skirt with application to the theory of screen printing. In other words, the general expressions predicting the pressure under a blade and the volume of coating fluid passing through the blade edge are derived. Using these expressions, the coating thickness on a piston skirt during a sample blade coating process can be quantitatively assessed.

Compression and Dewatering of Chinese Cabbage (배추의 압축탈수특성에 관한 연구)

  • Kim, Y.J.;Lee, D.H.;Lee, Y.B.
    • Journal of Biosystems Engineering
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    • v.19 no.1
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    • pp.3-8
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    • 1994
  • An experiment on the expression and dewatering of chinese cabbage was conducted in order to investigate its dewatering behavior. Chopped cabbage was packed into cylinder and pressed by piston upto the predetermined pressure on Instron-1000. The rates of dewatering were affected domintantly by the applied pressure, but not significantly by the packed amount of cabbage in the cylinder. The pressure effect was increased very abruptly at first, but the increase rate was very low at high pressure greater than 20 MPa, showing great deviation from linear dependence of flow rate on pressure in Darcy's Law. Therefore, water expression from cabbage was not Newtonian flow of water through cell wall. In fact, the squeezed water contained a lot of solid particles, about 3% of solid cabbage particles, showing destruction of cell wall. It appeared that compression and dewatering of vegetable wastes in the low pressure. under 20 MPa, is more desirable for later treatment of the dewater. More researches are needed in order to develop a treatment method for the solid particles in the expressed water before an expeller treatment system can be applied to vegetable wastes.

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A Basic Study on Blade Coating Process of Piston Skirt by Applying the Technology of Screen Printing - Parametric Study (스크린 프린팅 기술을 적용한 피스톤 스커트의 브레이드 코팅공정에 관한 기초연구 - 매개변수 연구)

  • Chun, Sang-Myung
    • Tribology and Lubricants
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    • v.25 no.6
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    • pp.414-420
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    • 2009
  • In this study, using the general expressions predicting the pressure under a blade and the volume of coating fluid passing through the blade edge, it is predicted the change of the coating wet film thickness related with various parameters determining the characteristics of this blade coating process. Using the results of this research, it can be found the optimized coating wet film thickness taking into account the parameters related with various coating process on various metal surfaces will be able to be predicted.

Modeling of the filling process during resin injection/compression molding

  • Chang, Chih-Yuan
    • Advanced Composite Materials
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    • v.16 no.3
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    • pp.207-221
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    • 2007
  • The filling process of resin injection/compression molding (I/CM) can be divided into injection and compression phases. During the resin injection the mold is kept only partially closed and thus a gap is present between the reinforcements and the upper mold. The gap results in preferential flow path. After the gap is filled with the resin, the compression action initiates and forces the resin to penetrate into the fiber preform. In the present study, the resin flow in the gap is simplified by using the Stokes approximation, while Darcy's law is used to calculate the flow field in the fiber mats. Results show that most of the injected resins enter into the gap during the injection phase. The resin injection time is extremely short so the duration of the filling process is determined by the final closing action of the mold cavity. Compared with resin transfer molding (RTM), I/CM process can reduce the mold filling time or injection pressure significantly.

Prediction of Water Penetration and Diffusion in Concrete Through FEM Analysis (FEM해석을 통한 콘크리트내 수분침투 및 확산 예측)

  • Yoo, Jo-Hyeong;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2010.05a
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    • pp.87-88
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    • 2010
  • A permeability of concrete is a very important factors evaluating durability. So, we are carrying out a lot of relational data bases and experiment regarding a permeability. In order to evaluate a permeability of concrete, we are proceeding study on the water penetration and diffusion in concrete by water pressure. Because a way to evaluate a permeability of concrete has a limit. We will present a good method of evaluating durability of concrete using the water penetration depth of concrete by water pressure. To carry this out, we executed experiment with penetration depth of concrete by water pressure and verified it though FEM analysis.

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Wave-blocking Efficiency of a Horizontal Porous Flexible Membrane

  • Cho, Il-Hyoung
    • International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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    • v.6 no.1
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    • pp.7-14
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    • 2003
  • The interaction of monochromatic incident waves with a submerged horizontal porous membrane is investigated in the context of two-dimensional linear hydro-elastic theory. It is assumed that the membrane is made of material with very fine pores so that the normal velocity of the fluid passing through the porous membrane is linearly proportional to the pressure difference between two sides of the membrane (e.g. Darcy's law). Using the Eigen-function expansion method, the wave-blocking performance of a submerged horizontal porous membrane is tested with various membrane tensions, porosities, lengths, and submerged depths. It is found that an optimal combination of design parameters exists for given water depth and wave characteristics.

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Flow Analysis of the Tube Type Marine Auto-Backwashing Fuel Oil Filter (튜브형 박용 자동역세 연료유 필터 내부의 유동해석)

  • Yang, Jang-Sik;Kim, Bong-Hwan;Park, Young-Bum
    • Journal of Advanced Marine Engineering and Technology
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    • v.33 no.4
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    • pp.578-587
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    • 2009
  • In this paper, the characteristics of incompressible flow in a tube type marine fuel oil filter have been investigated. Fluent program has been used to obtain the solutions for the problems of three-dimensional, turbulent fuel oil flow in a filtering system. The inlet flow field is assumed to be uniform. The velocity and pressure distributions were obtained using Darcy's law. The increase of inlet velocity for cleaning fuel oil may cause some problems like vibration of the filter element. It was also required to consider the distribution of cleaning velocity because the worst distribution of cleaning velocity may cause the local insufficient cleaning effect and furthermore the effective filtration area can be reduced. The simulated results show that the computer code can be successfully applied for simulation of the complex base oil flow through the porous media. This paper could be applied to the design of auto-backwashing filtering system as design factor.

CONVECTION IN A HORIZONTAL POROUS LAYER UNDERLYING A FLUID LAYER IN THE PRESENCE OF NON LINEAR MAGNETIC FIELD ON BOTH LAYERS

  • Bukhari, Abdul-Fattah K.;Abdullah, Abdullah A.
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.11 no.1
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    • pp.1-11
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    • 2007
  • A linear stability analysis applied to a system consist of a horizontal fluid layer overlying a layer of a porous medium affected by a vertical magnetic field on both layers. Flow in porous medium is assumed to be governed by Darcy's law. The Beavers-Joseph condition is applied at the interface between the two layers. Numerical solutions are obtained for stationary convection case using the method of expansion of Chebyshev polynomials. It is found that the spectral method has a strong ability to solve the multilayered problem and that the magnetic field has a strong effect in his model.

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A Basic Study on Blade Coating Process of Piston Skirt by Applying the Technology of Screen Printing - Case Study (스크린 프린팅 기술을 적용한 피스톤 스커트의 브레이드 코팅공정에 관한 기초연구 - 사례연구)

  • Chun, Sang-Myung
    • Tribology and Lubricants
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    • v.26 no.2
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    • pp.142-148
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    • 2010
  • The purpose of this study is to find how to be formed the wet film thickness during the low friction coating process for a piston skirt with application to the theory of screen printing. In other words, in this research, it is to derive the general expressions predicting the pressure under a blade and the volume of coating fluid passing through the blade edge. Using these expressions, it is to be approved that the current operation characteristics of a screen printing system to a sample blade coating process for low friction coating on a piston skirt can be quantitatively assessed.

Deformation Analysis of Semi-Solid Aluminum Material Considering Seperation Phenomena of Solid Particles (고상입자의 분리현상을 고려한 Semi-Solid 알루미늄재료의 변형해석)

  • 최진석;강충길;김기훈
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.03a
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    • pp.98-105
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    • 1997
  • The behaviour of alloys in the semi-solid state strongly depends on the imposed stress state and on the morphology of the phase which can very from dendritic to globular. The estimation of behaviour characteristic in the compression simulation with seim-solid materials are calculated by finite element method with proposed algorithm. The proposed theoretical model and a various boundary conditions for compression process is investigated with the coupling calculation between the liquid phase flow and the solid phase deformation. The simulation process considering soldification phenomena is performed to the isothermal conditions of two dimensional problems. To analysis of compression process by using semi-solid materials, a new stress-strain relationship is described, and compression analysis is performed by viscoelastic model for the solid phase and the Darcy's law for the liquid flow. The calculated results for compression force and ram displacement will be compared to experimental data.

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