• 제목, 요약, 키워드: Porous Media

검색결과 554건 처리시간 0.04초

다공성 매질의 건조 해석 (COMPUTATIONAL ANALYSIS ON DRYING OF POROUS MEDIA)

  • 이주석;이창환;배영민;문영준
    • 한국전산유체공학회:학술대회논문집
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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.

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CH4/O2 혼합기의 2단 다공체 내 부분산화 개질에 관한 실험적 연구 (Experimental Study on the Partial Oxidation Reforming of CH4/O2 Mixture in Two-Section Porous Media)

  • 곽영태;이대근;고창복
    • 한국연소학회:학술대회논문집
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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.

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Meshfree consolidation analysis of saturated porous media with stabilized conforming nodal integration formulation

  • Wang, Dongdong;Xie, Pinkang;Lu, Hongsheng
    • Interaction and multiscale mechanics
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    • v.6 no.2
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    • pp.107-125
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    • 2013
  • A strain smoothing meshfree formulation with stabilized conforming nodal integration is presented for modeling the consolidation process in saturated porous media. In the present method, nodal strain smoothing is consistently introduced into the meshfree approximation of strain and pore pressure gradient variables associated with the saturated porous media. Meanwhile, in order to achieve a consistent numerical implementation, a smoothing approximation of the meshfree shape function within a nodal representative domain is also proposed in the stiffness construction. The resulting discrete system of equations is all expressed in smoothed nodal measures that are very efficient for numerical evaluation. Subsequently the space-time fully discrete equations are further established by the generalized trapezoidal rule for time integration. The effectiveness of the proposed meshfree consolidation analysis method is systematically illustrated by several benchmark problems.

불포화 다공성 매질체의 공기-물 경계면 비표면적 계산모델 분석 (Analysis of Calculation Model for Specific Air-water Interface Area in Unsaturated Porous Media)

  • 김민규;김성배;박성직
    • 한국농공학회논문집
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    • v.48 no.5
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    • pp.83-93
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    • 2006
  • In unsaturated porous media, the air-water interface (AWI) plays an important role in removing of biocolloids such as bacteria, viruses, and protozoan (oo)cysts. In this study, four models related to calculation of specific AWI area are analyzed to determine the appropriate model, and the selected models are verified using the previously reported experimental data. The results indicate that the modified model from Niemet et al. (2002) is the most appropriate tool for calculating the specific AWI area using the van Genuchten (1980) parameters obtained from the water retention curve. Hence, it is expected that this model could be used to quantitatively determine the attachment of biocolloids to AWI in the transport modeling of biocolloids in unsaturated porous media.

Cryogenic flow behavior in porous media with experimental approach

  • Choi, Sung-Woong;Kwon, Jae-Sung;Kim, Bum-Soo;Yang, Jeong-Hyeon
    • 한국마린엔지니어링학회지
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    • pp.818-822
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    • 2018
  • When applied to transportation, cryogenic technology uses the efficiency of volume reduction due to gas liquefaction. Much research is underway with the technology expanding to applications for defense and medicine. To use cryogenic technology, an understanding of the entire system, including that of the behavior of cryogenic fluids and the related heat transfer, is essential. In this study, experiments were conducted to investigate the behavior of a cryogenic fluid in a porous medium, which is widely used in cryogenic systems. Results showed that the pressure distribution in the porous medium was nonlinear with a positive curvature. By introducing a mass sink term in the mass conservation equation, this pressure distribution could be explained. In contrast, the pressure distribution in porous media under saturated flow conditions is constant.

사용후핵연료 저장용기 유로입출구의 다공성매질 모델링 및 열해석 검증평가 (Porous Media Modelling and Verification of Thermal Analysis for Inlet and Outlet Ducts of Spent Fuel Storage Cask)

  • 이주찬;방경식;최우석;서기석;고성호
    • 방사성폐기물학회지
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    • v.16 no.2
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    • pp.223-232
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    • 2018
  • 사용후핵연료 저장용기의 공기 흡입구 및 배기구에는 외부환경으로부터 이물질의 유입을 방지하기 위하여 bird screen이 설치되며, bird screen에서는 공기의 유동 저항이 발생하게 된다. 본 연구에서는 Bird screen mesh의 단순화 모델을 이용한 열해석을 수행하기 위하여 다공성매질 해석모델을 개발하였다. CFD 해석을 이용하여 다공성매질에 대한 유동저항계수를 산출하고 이에 대한 신뢰성을 입증하였다. 다공성매질 해석모델을 이용하여 콘크리트 저장용기의 열해석을 수행하고 bird screen을 갖는 콘크리트 저장용기의 열시험을 수행하였다. Bird screen mesh를 고려한 열시험 결과와 다공성매질을 고려한 열해석 결과를 비교하였으며, 해석 및 시험결과가 서로 잘 일치하였다. 해석결과는 시험결과에 비하여 다소 높은 온도분포를 보여 다공성매질을 사용한 콘크리트 저장용기의 열해석 결과에 대한 신뢰성 및 보수성이 입증되었다.

An experimental study on positioning conformance control of starch gelant in the heterogeneous porous media by using CT technology

  • Zhang, Lei;Xu, Hongming;Pu, Chunsheng;Yuan, Guangyu;Leng, Guangyao;Zhang, Chunlei
    • Journal of Industrial and Engineering Chemistry
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    • v.54
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    • pp.107-116
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    • 2017
  • In order to increase the economic efficiency of conformance control in the time of low oil price, a gelant should be injected into the specified location (positioning conformance control) to improve the swept volume in the maximum extent in the heterogeneous oil reservoir. For this purpose, an in-situ cross-linking polymer gelant (it is consisting of modified starch, acrylamide, N, N'- methylene diacrylamide, and potassium persulfate) is taken as the object of study by CT scan. Based on the dynamic and visible images of fluids distribution in the porous media, the gelant can be used to achieve the positioning conformance control because it can almost maintain a whole slug during transportation in porous media. According to the relationship of transportation distance and injection volume of the gelant in porous media, the gelant can be displaced to the specified location in porous media. In addition, the characteristics of water flooding of heterogeneous porous media before and after positioning conformance control are studied by CT scan, which can investigate the function of positioning conformance control and the extent of improving the swept volume in the heterogeneous reservoirs. The experimental results in this paper can provide theoretical guidance for the practical application of positioning conformance control in the heterogeneous oil reservoirs.

다공성 연소기 모델로서의 다중 채널 연소기 내부 화염의 안정화 특성 기초 연구 (Basic Study on Flame-Stabilization Characteristics in a Multi-Channel Combustor via a Model of a Porous-Media Combustor)

  • 박승일;이민정;김남일
    • 대한기계학회논문집B
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    • v.35 no.8
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    • pp.815-823
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    • 2011
  • 다공성 물질 내부의 연소 현상은 저발열량 연료의 연소 및 연소열의 재생을 위한 수단으로 다양한 형태로 산업현장에 응용되고 있다. 하지만 다공성 물질 내부에서의 연소 현상은 직접적인 관찰이 힘들다는 점과 다공성 물질의 복잡한 내부 구조로 인해 매우 제한적인 연구가 진행되어 왔다. 본 연구에서는 복잡한 다공성 물질의 구조 내부에서의 화염의 안정화 특성에 관한 이해를 위해 내부 관찰이 가능하도록 다수의 석영판으로 구성된 다중채널 형태의 모형 연소기를 제안하고 이를 이용한 간단한 실험 결과를 제시한다. 그리고 이러한 다중채널내부 화염의 안정화에 관한 간단한 기초해석 모델을 제안한다. 다수의 채널 내부에 형성된 화염은 채널간의 열전달에 의해 화염의 공간 분포가 변화하고 그 결과로 연소기 내부의 가연한계에 변화가 발생한다. 채널의 재료 특성 및 당량비에 따른 가연한계의 변화를 제시하였으며, 이 결과는 다공성 연소기 내부화염의 이해에 도움될 것이다.

다공성 미디어를 충진한 혐기-호기 반응조를 이용한 하수고도처리에 관한 연구 (Advanced Wastewater Treatment Using Anoxic-Aerobic Reactor Filled with Porous Media)

  • 김동하
    • 상하수도학회지
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    • v.21 no.1
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    • pp.83-89
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    • 2007
  • A biological anoxic-aerobic reactor filled with porous media was operated in lab scale for the advanced wastewater treatment. The experiments were conducted for 6 months with three HRTs (4, 6, 8hr) and temperature of $23{\sim}25^{\circ}C$. Some other experimental conditions were as follows; nitrification reactor (MLSS 4,500mg/L, DO 3.3mg/L, $23{\sim}28^{\circ}C$), denitrification reactor(MLSS 8,000mg/L, ORP -100mV, Temp.$19{\sim}23^{\circ}C$). Average removal efficiencies of SS, $BOD_5$, $COD_{Cr}$, T-N, and T-P were 97.8%, 95.5%, 94.5%, 80.2%, and 60.6%, respectively. The reactor filled with porosity media showed stable removal capacity for organics and nutrients. Fast and complete nitrification and denitrification were accomplished. Maintaining high MLSS with porous media in the nitrification and denitrification reactor appears to enhance the nitrogen removal process. For the higher T-P removal, some coagulant addition process will be needed.

사각 기둥 실린더 내부 다공성 매질에서의 액화질소의 거동에 대한 연구 (Study on Flow behavior of Liquid Nitrogen for Porous Media in Square-section Cylinder)

  • 최성웅;이우일
    • 한국가스학회지
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    • v.17 no.1
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    • pp.26-34
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    • 2013
  • 상 변화(phase change)를 수반한 다상 유동 연구(multiphase flow analysis)는 증발, 응축과 같은 많은 분야에 적용, 응용될 수 있고 현상의 복잡성 때문에 많은 연구의 관심을 받고 있는 분야이다. 본 연구에서는 극저온 유체인 액화질소가 다양한 밀도의 글라스 울 내부 다공성 매질속으로 스며들면서 나타나는 거동을 살펴보았다. 유동에 영향을 미치는 투과성 계수에 대해서, 외부 압력의 영향성에 대한 실험을 진행하였고 논의하였다. 극저온 유체인 액화질소를 실험유체로 사용하여 사각 기둥 실린더 내부의 유체의 유동에 대한 실험으로 유체의 유동을 살펴보았다. 그 결과 벌크 밀도가 커짐에 따라 투과성 계수가 작아지고, 거리에 따른 압력변화의 비선형성이 커짐을 보였다. 마지막으로 CFD 전산유동 프로그램으로 실험결과와 동일한 상황을 모사하였으며, 이를 실험결과와 비교 분석하였다. 이에 대한 검증결과, 시뮬레이션 결과가 실험결과와 유사한 경향과 결과를 보여주었다.