• Title/Summary/Keyword: Porous medium

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Theoretical Formulation of Porous Medium Behavior Depending on Degree of Saturation (포화도에 따른 다공질 매체 거동의 이론적 정식화)

  • Park, Tae Hyo;Jung, So Chan;Kim, Won Cheul
    • Journal of the Korean GEO-environmental Society
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    • v.2 no.3
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    • pp.81-88
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    • 2001
  • The behavior of porous medium is modeled by linear thermoporoelastic behavior, linear poroviscoelastic behavior, poroplastic behavior, and poroviscoplastic behavior, etc. The behavior has, in general, a complicated aspect which makes a mechanical description of the problem with time. Constitutive modeling for deformation behavior of porous medium with coupling effects is needed since there is interaction between the constituents in pores with a relative velocity to each other. In this work, it is explained 3-dimensional behavior depending on degree of saturation for porous medium composed of homogeneous, isotropic materials. It is obtained the governing equations based on continuum porous mechanics. In addition, it is developed constitutive model which can be understood of behavior for porous medium which can be understood, analysed behavior of porous medium. It can be accomplished exact analysis and prediction of behavior in porous medium. The behavior for porous medium is analysed exactly, and the prediction of deformation behavior is accomplished. Consequently, it will be basis to analyze 3-dimensional behavior in municipal solid waste landfill, and the practical using of porous medium ground which are composed of nonhomogeneous, anisotropic materials can be done widely.

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The Premixed Flame in a Radiatively Active Porous Medium (복사열전달을 동반하는 다공성 매질내의 예혼합 화염)

  • 김정수;백승욱
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.13 no.2
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    • pp.265-270
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    • 1989
  • The present study considers the thermal structure variation in a porous medium caused by changing the most important radiative property of porous medium, absorption coefficient, as well as altering the physical dimension of porous medium and the equivalence ratio of premixed gas mixture. The radiation model was introduced as an unsteady differential form using the two-flux gray radiation model. The role of the conductive heat transfer through both gas phase and porous medium was found to be almost insignificant compared with that of the radiative heat transfer. The reaction zone shifted upstream and the flame thickness decreased as either the geometrical length of porous medium increased or the absorption coefficient decreased.

Forced Convection in a Circular Pipe with a Partially Filled Porous Medium

  • Kim, Woo-Tae;Hong, Ki-Hyuek;Myung S. Jhon;John G. VanOsdo;Duane H. Smith
    • Journal of Mechanical Science and Technology
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    • v.17 no.10
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    • pp.1583-1596
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    • 2003
  • A study of forced convection in a circular pipe with a partially filled porous medium was numerically investigated. The Brinkman-Forchheimer extension of the Darcy model was used to analyze the and temperature distribution in the porous medium. Our study includes two types of porous layer configurations: (1) a layer attached at the tube wall extending inward towards the centerline and (2) a layer at the centerline extending outward. The effect of several parameters, such as Darcy number, effective viscosity, effective thermal conductivity, and inertia parameter, as well as the effect of geometric parameters, were investigated.

RADIATION EFFECTS ON MHD BOUNDARY LAYER FLOW OF LIQUID METAL OVER A POROUS STRETCHING SURFACE IN POROUS MEDIUM WITH HEAT GENERATION

  • Venkateswarlu, M.;Reddy, G. Venkata Ramana;Lakshmi, D. Venkata
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.19 no.1
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    • pp.83-102
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    • 2015
  • The present paper analyses the radiation effects of mass transfer on steady nonlinear MHD boundary layer flow of a viscous incompressible fluid over a nonlinear porous stretching surface in a porous medium in presence of heat generation. The liquid metal is assumed to be gray, emitting, and absorbing but non-scattering medium. Governing nonlinear partial differential equations are transformed to nonlinear ordinary differential equations by utilizing suitable similarity transformation. The resulting nonlinear ordinary differential equations are solved numerically using Runge-Kutta fourth order method along with shooting technique. Comparison with previously published work is obtained and good agreement is found. The effects of various governing parameters on the liquid metal fluid dimensionless velocity, dimensionless temperature, dimensionless concentration, skin-friction coefficient, Nusselt number and Sherwood number are discussed with the aid of graphs.

Investigation on the heat transfer of MHD nanofluids in channel containing porous medium using lattice Boltzmann method

  • Xiangyang Liu;Jimin Xu;Tianwang Lai ;Maogang He
    • Advances in nano research
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    • v.15 no.3
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    • pp.191-201
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    • 2023
  • In order to develop better method to enhance and control the flow and heat transfer inside the radiator of electronic device, the synergistic effect of MHD nanofluids and porous medium on the flow and heat transfer in rectangular opened channel is simulated using Lattice Boltzmann method. Three nanofluids of CuO-water, Al2O3-water and Fe3O4-water are studied to analyze the influence of the type of nanofluid on the synergistic effect. The simulation results show that the porous medium can increase the flow velocity in fluid zone adjacent to the porous medium and enhance the heat transfer on the surface of the channel. Under no magnetic field, when the porosity of porous medium is 0.8, the Nusselt number is 4.46% higher than when the porosity is 0.9. Al2O3-water has the best heat transfer effect among the three nanofluids. At Ф=0.06, Ha=100, θ=90°, ε=0.9, Nu of Al2O3-water is 6.51% larger than that of CuO-water and 5.05% larger than that of Fe3O4-water. Magnetic field enhances seepage in porous medium and inhibits heat transfer in the bottom wall. When Ha=30 and 60, the inhibiting effect is the most significant as the magnetic field angle is 90°. And when Ha=100, the inhibiting effect is the most significant as the magnetic field angle is 120°.

Numerical Study on Flow Characteristics of Hollow Fiber Membrane Module for Water Recovery Cooling Tower (수분회수 냉각탑에 적용되는 중공사막 모듈의 유동특성에 관한 수치해석적 연구)

  • Park, Sang Cheol;Park, Hyun Seol;Lee, Hyung Keun;Shin, Weon Gyu
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.8
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    • pp.537-544
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    • 2017
  • The purpose of this study is to analyze the flow characteristics when a staggered hollow fiber membrane module is modeled as a porous medium. The pressure-velocity equation was used for modeling the porous medium, using pressure drop data. In terms of flow characteristics, we compared the case of the "porous medium" when the membrane module was modeled as a porous medium with the case of the "membrane module" when considering the original shape of the membrane module. The difference in pressure drop between the "porous medium" and "membrane module" was less than 0.6%. However, the maximum flow velocity and mean turbulent kinetic energy of the "porous medium" were 2.5 and 95 times larger than those of the "membrane module," respectively. Our results indicate that modeling the hollow fiber module as a porous medium is useful for predicting pressure drop, but not sufficient for predicting the maximum flow velocity and mean turbulent kinetic energy.

On the Thermal Boundary Conditions at the Interface Between the Porous Medium and the Impermeable Wall (다공성 매질과 비투과성 벽면 사이의 경계면에 대한 열적 경계 조건)

  • Kim, Deok-Jong;Kim, Seong-Jin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.12
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    • pp.1635-1643
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    • 2000
  • The present work investigates a heat transfer phenomenon at the interface between a porous medium and an impermeable wall. In an effort to appropriately describe the heat transfer phenomenon at the interface, the heat transfer at the interface between the microchannel heat sink, which is an ideally organized porous medium, and the finite-thickness substrate is examined. From the examination, it is clarified that the he heat flux distribution at the interface is not uniform for the impermeable wall with finite thickness. On the other hand, the first approach, based on the energy balance for the representative elementary volume in the porous medium, is physically reason able. When the first approach is applied to the thermal boundary condition, and additional boundary condition based on the local thermal equilibrium assumption at the interface is used. This additional boundary condition is applicable except for the very th in impermeable wall. Hence, for practical situations, the first approach in combination with the local thermal equilibrium assumption at the interface is suggested as an appropriate thermal boundary condition. In order to confirm our suggestion, convective flows both in a microchannel heat sink and in a sintered porous channel subject to a constant heat flux condition are analyzed. The analytically obtained thermal resistance of the microchannel heat sink and the numerically obtained overall Nusselt number for the sintered porous channel are shown to be in close agreement with available experimental results when our suggestion for the thermal boundary conditions is applied.

HYDROMAGNETIC FLUCTUATING FLOW OF A COUPLE STRESS FLUID THROUGH A POROUS MEDIUM

  • Zakaria, M.
    • Journal of applied mathematics & informatics
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    • v.10 no.1_2
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    • pp.175-191
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    • 2002
  • The equations of a polar fluid of hydromagnetic fluctuating through a porous medium axe cast into matrix form using the state space and Laplace transform techniques the resulting formulation is applied to a variety of problems. The solution to a problem of an electrically conducting polar fluid in the presence of a transverse magnetic field and to a problem for the flow between two parallel fixed plates is obtained. The inversion of the Laplace transforms is carried out using a numerical approach. Numerical results for the velocity, angular velocity distribution and the induced magnetic field are given and illustrated graphically for each problems.

ANALYTICAL SOLUTION OF COUPLED RADIATION-CONVECTION DISSIPATIVE NON-GRAY GAS FLOW IN A NON-DARCY POROUS MEDIUM

  • Darvishi, Mohammad Taghi;Khani, Farzad;Aziz, Abdul
    • Journal of applied mathematics & informatics
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    • v.28 no.5_6
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    • pp.1203-1216
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    • 2010
  • The homotopy analysis method (HAM) has been applied to develop an analytic solution for the coupled radiation-convection dissipative non-gray gas flow in a non-Darcy porous medium. Results are presented for the surface shear and temperature profiles are presented to illustrate the effect of various parameters appearing in the analytical formulation. The accuracy and convergence of the method is also discussed.

Porous Medium Theory in Consolidation (다공체 이론과 입밀해석)

  • Seo, Young-Kyo
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2002.10a
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    • pp.108-112
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    • 2002
  • 다공체 이론은 간극수압 및 토질입자 및 간극수의 상호 작용을 포함하는 여러 가지 지반관련 문제의 이해에 있어 매우 중요하다. 이러한 상호작용은 토질강도 및 변형에 중요한 영향을 미친다. 본 논문은 다공체 이론(porous medium theory)의 일반식 및 구성모델을 제시하고 그에 따른 유한요소 공식을 유도하였다. 압밀 예제로서 이러한 모델의 정확도를 검증하였다.

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