• Geomechanics and Engineering
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• 제9권1호
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• pp.15-24
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• 2015

The porosity is often regarded as a linear function of fluid pressure in porous media and permeability is approximately looked as constants. However, for some scenarios such as unconsolidated sand beds, abnormal high pressured oil formation or large deformation of porous media for pore pressure dropped greatly, the change in porosity is not a linear function of fluid pressure in porous media, and permeability can't keep a constant yet. This paper mainly deals with the relationship between the damage variable and permeability properties of a deforming media, which can be considered as an exploratory attempt in this field.

• 대한기계학회논문집A
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• 제28권7호
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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.

• 상하수도학회지
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• 제21권6호
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• pp.755-761
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• 2007

Disinfection performance in clearwell is generally measured by CT, which is expressed by $C{\times}T$. C is represented by disinfection concentration, and T is represented by $T_{10}$ which means 90% contact time in clearwell. In order to improve Disinfection performance, augmentation of $T_{10}$ is required. Guide wall has been generally used to improve $T_{10}$ because $T_{10}$ changes according to flow field. In this study, porous media is proposed instead of guide wall, and disinfection performance between guide wall and porous media wall are compared. Flow field and $T_{10}$ in each clearwell are investigated as well. Improved Disinfection performance appear in case of porous media wall compare to guide wall, and best performance occur in porosity factor ${\beta}$ 1e+4.

• 대한환경공학회지
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• 제27권5호
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• pp.542-548
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• 2005

부착 미생물을 이용한 다공성 담체 유동상 반응기는 하폐수중의 유기물 및 질소제거에 많이 적용되어져 왔다. 특히 생물막이 형성된 담체에서는 호기, 무산소 그리고 혐기영역이 공존하여 동시적 질산화/탈질 반응에 의한 질소제거에 유리한 환경이 제공된다고 알려져 있다. 이러한 반응을 활성화시키기 위해서는 담체표면과 내부에서 산소와 유기물등의 적절한 기질확산이 이루어져야 한다. 그러나 하폐수중의 유기물농도나 생물막의 마찰조건등 운전조건에 따라서는 표면에서의 종속영양균의 과잉성장에 의해 질소 제거 반응이 저해되기도 한다. 다공성 담체 유동상 반응기에 막모듈을 결합시킨 하이브리드 반응기는 단일조내에서 활성화된 동시적 질산화/탈질 반응으로 종래의 유동상 반응기에 비해 30% 이상 질소제거 효율이 증가하였다. 미소전극 연구를 통해 담체내부의 탈질율을 조사할 수 있으며 유동상 반응기에 비하여 하이브리드 반응기내 담체내부에서는 탈질반응에 대한 유기물의 확산에 대한 제한인자가 작으며 따라서 보다 높은 탈질율을 유지할 수 있음을 보였다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.661-668
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• 2003

This paper presents Lattice-Boltzmann simulation techniques for single-phase and two-phase fluid flow in porous media. Numerical experiments were performed in a digital rock sample from X-ray microtomography. Computed results showed very good agreement with laboratory measurements of permeability and relative permeability. Two applications using these simulation techniques show the potential of the Lattice-Boltzmann flow simulation to solve many difficult problems coupled with fluid flow in porous media.

• 한국전산구조공학회논문집
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• 제23권6호
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• pp.693-702
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• 2010

In this paper, FETI(Finite Element Tearing and Interconnecting) method is introduced in order to improve numerical efficiency of Staggered method. The porous media theory, the Staggered method and the FETI method are briefly introduced in this paper. In addition, we account for the MPI(Message Passing Interface) library for parallel analysis, and the proposed combined Staggered method with FETI method. Finally Lagrange multipliers and CG(Conjugate Gradient) algorithm to solve decomposed domain are proposed, and then the proposed method is verified to be numerically efficient by MPI library.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.447-450
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• 1997

Temperature distribution measurements in the mockup apparatus of reactor vessel were performed to determine the effective thermal conductivity of Al powder porous media where stainless steel tubes were installed with different geometry. The temperature distributions at four separated sections with different arrangements of porous media have different slopes according to the geometrical configuration. From the measured temperature distribution, effective thermal conductivity have been derived using the least square fitting method.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.249-251
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• 2014

Synthesis gas such as hydrogen and carbon monoxide was produced from $CH_4//oxygen$ mixture using two-section porous media combustor. Heat recirculation through the inner foam structure could extend the flow velocity of stable region over the laminar burning velocity. $H_2/CO$ ratio and module M from concentration of flue gas measured by Gas Chromatography was similar to those calculated by equilibrium. But it was made sure that the heat loss effect becomes more influential than heat recirculation effect as the mixture gets richer. To generate synthesis gas appropriate for methanol production, insulated pressurized porous media combustor will be designed and built in the future.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 추계학술대회논문집
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• pp.145-150
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• 2009

In this study, characteristics of microwave and convective drying are studied by using a multiphase porous media model. Temperature and moisture profiles for hot-air convective heating and microwave heating of 1-D porous media with varying time and space are numerically investigated. This result shows the microwave drying method is more effective than the convective drying method. Comparing to convective drying, microwave drying can increase temperature and evaporation rate significantly since microwave generates internal heat and increases internal pressure, which results in moisture movement toward the surface on which moisture is vaporized.

• 설비공학논문집
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• 제3권5호
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• pp.386-394
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• 1991

Freezing of saturated porous media contained in a rectangular cavity has been studied experimentally. Water and different diameter glass beads consitituted the liquid and porous media. Solidification front shape, the effects of bead diameter and initial liquid temperature was investigated. When the hot wall temperature was below $4^{\circ}C$, the freezing rate was higher at the top than at the bottom due to the density inversion, but with increasing the hot wall temperature the freezing rate at the top was effected by the liquid temperature and was lower than at the bottom. With increasing the bead diameter, the difference of freezing rate between top and bottom was increased and depends on thermal conductivity. When the liquid temperature was low in the beginning, the freezing rate was high, but with increasing the time almost the same with those of high temperature liquid.