The investigation of bubble mobility in channel flow with wavy porous media walls

Gangloff Jr., John J.,Hwang Jr., Wook R.,Advani Jr., Suresh G. Elsevier 2015 International journal of multiphase flow Vol.70 No.-

<P><B>Abstract</B></P> <P>During composites processing, thermoset polymer resin is injected into network of densely packed continuous fibers with the goal of complete saturation. The formation and entrapment of gas bubbles, due to the presence of air or volatiles during processing, will create voids in the cured composite. Voids can degrade the mechanical properties and increase design risks and costs. Thus, there is a need to understand the two phase flow of resin and bubbles through channels within fibrous porous media. A two-phase flow model of a channel containing resin and gas bubbles is presented. The boundaries of the channel are porous media with sinusoidal wavy or corrugated walls, which represents the wavy nature of the porous media. This causes the change in bubble movement dynamics, due to the non-uniform pressure gradient induced by non-rectilinear walls. Parameters such as porous media permeability, channel waviness, and channel width are studied to investigate the influence of wavy porous wall effects on the two-phase flow and how these parameters may influence the likelihood of bubble entrapment. By maximizing the bubble mobility, which is the ratio of average bubble velocity to average resin velocity, one can remove the bubbles from the system before the resin cures.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A 2D resin flow through a wavy or corrugated channel+porous media is modeled. </LI> <LI> Wavy channel+porous media flow is compared to wavy channel+slip velocity model. </LI> <LI> 2D resin flow shows good matching of slip velocity model versus porous media solution. </LI> <LI> Two-phase bubble flow through a cylindrical wavy channel+porous media is modeled. </LI> <LI> Results show the ideal waviness and channel width for maximized bubble mobility. </LI> </UL> </P>

An enhanced incompressible SPH method for simulation of fluid flow interactions with saturated/unsaturated porous media of variable porosity

Shimizu, Yuma,Khayyer, Abbas,Gotoh, Hitoshi Techno-Press 2022 Ocean systems engineering Vol.12 No.1

A refined projection-based purely Lagrangian meshfree method is presented towards reliable numerical analysis of fluid flow interactions with saturated/unsaturated porous media of uniform/spatially-varying porosities. The governing equations are reformulated on the basis of two-phase mixture theory with incorporation of volume fraction. These principal equations of mixture are discretized in the context of Incompressible SPH (Smoothed Particle Hydrodynamics) method. Associated with the consideration of governing equations of mixture, a new term arises in the source term of PPE (Poisson Pressure Equation), resulting in modified source term. The linear and nonlinear force terms are included in momentum equation to represent the resistance from porous media. Volume increase of fluid particles are taken into consideration on account of the presence of porous media, and hence multi-resolution ISPH framework is also incorporated. The stability and accuracy of the proposed method are thoroughly examined by reproducing several numerical examples including the interactions between fluid flow and saturated/unsaturated porous media of uniform/spatially-varying porosities. The method shows continuous pressure field, smooth variations of particle volumes and regular distributions of particles at the interface between fluid and porous media.

Flow resistance of viscoelastic flows in fibrous porous media

Liu, H.L.,Wang, J.,Hwang, W.R. Elsevier Scientific Pub. Co 2017 Journal of non-Newtonian fluid mechanics Vol.246 No.-

<P>In this work, we present flow simulations of viscoelastic (Oldroyd-B and Leonov) fluids in the unidirectional fibrous porous media to investigate effects of the elasticity on the flow resistance. Extensive numerical simulations were carried out for the Oldroyd-B and Leonov fluids to investigate the flow resistance in some typical geometries of unidirectional fibrous porous media: square, hexagonal, as well as randomly aligned arrays of unidirectional fibers. To the best knowledge of the authors, we report for the first time the stiff increase of flow resistance through numerical simulations above a certain Weissenberg number. Considerable growth in the flow resistance has turned out to be closely associated with microstructure of porous media through the extensional stretch of polymers. For the hexagonal and randomly aligned fibers, where there are enough spaces behind fibers, significant amount of polymer stretch is observed along with substantial growth of the corresponding flow resistance. On the other hand, only minor change in flow resistance and negligible polymer stretch are observed in case of square-packing porous media. (C) 2017 Elsevier B.V. All rights reserved.</P>

소결다공체를 적용한 Closed Type 모사바이오파일시스템의 TPH 분해 특성

정현규,최상일,김상국,김혜진,김유범 한국토양비료학회 2011 한국토양비료학회지 Vol.44 No.3

This research was conducted to verified the effectiveness of a sintered porous media coated with organic matter as nutrient source and microorganisms as decomposer effective in TPH decomposition for a closed-typed biopole system. The organic matter content in the sintered porous media which was developed with bentonite increased with increasing dilution ratio of pig slurry and the sintered porous media as well as decrease in the particle size of sintered porous media. The decomposition rate of TPH was significantly increased with increasing aeration than that under atmospheric condition. Also the sintered porous media containing organic matter and microorganisms proved that the decomposition was enhanced with addition of nutrients sources in addition to aeration periodically.

Coupled Discrete Crack and Porous Media Model for Hydraulic Fractures using the XFEM

Bo He,Xiaoying Zhuang 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.3

A hydromechanical model for investigating fluid flow in the fractured porous media is presented in this study. The hydromechanical coupling equations are derived from the mass and momentum balance equation for the saturated porous media. The extended finite element method is employed to model the discontinuity for fluid flow and cracks inside the porous media. The Newton-Raphson method is utilized for solving the nonlinear coupling equation with an implicit time integration scheme. Finally, examples are presented to demonstrate the effectiveness of the presented model. Fracture propagation in the porous media under the influence of the preexisted pressurized zone is also studied. It is found that the cracks and preexisted pressurized region have a significant impact on the fluid flow and deformation patterns.

Physical and CFD Simulated Models to Analyze the Contaminant Transport through Porous Media under Hydraulic Structures

Sadiq S. Muhsun,May Samir Saleh,Ali R. Qassim 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.12

In this paper the efforts were made in the laboratory to construct a physical model and a simulated model with the help of computational fluid dynamic (CFD) techniques to provide the solutions of contaminant transport within the saturated porous media under a hydraulic structure. Brinkman equations with Forchheimer correction and species flow through porous media were considered together to describe the problem. Three categories factors were considered to be analyzed in this study. The first one is the hydraulic factors represented in the upstream water head (H). While, the second factor is the geometry of the hydraulic structures represented in the length of the base and the length of the sheet pile. The physical properties and chemical properties were the third investigated factors, in which the physical properties of the porous media include porosity and intrinsic permeability, while the chemical properties represented by the rate of generation and retardation caused by the adsorption. The physical properties have a slight effect on the concentrations because of the low flow velocity through the porous media. On the other hand, a considerable decrement on the concentrations were noticed when the rate of generation and retardation caused by adsorption was increased. Also, it was observed that the diffusion coefficient has no dramatic effect on the concentrations and contaminant moving. The results of the CFD simulated model and that of the physical model were verified with two cases for pressure head and one case for the contaminates transport. For the first case of pressure head, the maximum percentage error at five selected points was about 15% at worst point with average error of 10%. While, for the case two, the maximum percentage error is about 9% at worst one with an average error of 8%. For the simulation of the contaminates transport, reliable statistical indexes error indicted that the CFD simulated model gives a good agreement with all experimental results.

Biocolloid transport and deposition in porous media: A review

Hongjuan Bai,Junhang Chen,Yumu Hu,Gang Wang,Wenju Liu,Edvina Lamy 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.1

In an effort to protect surface and groundwater supplies from contamination, to assess the risk of microbial groundwater contamination and for the purpose of soil bioremediation, considerable efforts have been made to investigate biocolloid transport and retention in porous media. The current work provides an introductory overview of biocolloid transport and deposition in porous media so as to have a better understanding of the environmental behavior of biocolloids. In this review, biocolloid transport and deposition in porous media are discussed with an emphasis on transport and deposition mechanisms, numerical modeling and influencing factors. Moreover, major findings with respect to the forces acting on biocolloid transport and deposition are addressed, and research methods used to study biocolloid transport and deposition in porous media are also presented. Finally, based on the reported results, future research perspectives considering the microscopic pore scale study for biocolloid transport and deposition in porous media are also suggested.

Solution verification procedures for modeling and simulation of fully coupled porous media: static and dynamic behavior

Tasiopoulou, Panagiota,Taiebat, Mahdi,Tafazzoli, Nima,Jeremic, Boris Techno-Press 2015 Coupled systems mechanics Vol.4 No.1

Numerical prediction of dynamic behavior of fully coupled saturated porous media is of great importance in many engineering problems. Specifically, static and dynamic response of soils - porous media with pores filled with fluid, such as air, water, etc. - can only be modeled properly using fully coupled approaches. Modeling and simulation of static and dynamic behavior of soils require significant Verification and Validation (V&V) procedures in order to build credibility and increase confidence in numerical results. By definition, Verification is essentially a mathematics issue and it provides evidence that the model is solved correctly, while Validation, being a physics issue, provides evidence that the right model is solved. This paper focuses on Verification procedure for fully coupled modeling and simulation of porous media. Therefore, a complete Solution Verification suite has been developed consisting of analytical solutions for both static and dynamic problems of porous media, in time domain. Verification for fully coupled modeling and simulation of porous media has been performed through comparison of the numerical solutions with the analytical ones. Modeling and simulation is based on the so called, u-p-U formulation. Of particular interest are numerical dispersion effects which determine the level of numerical accuracy. These effects are investigated in detail, in an effort to suggest a compromise between numerical error and computational cost.

Adoption of Homotopy Perturbation Method (HPM) for non-Darcy Flow in Porous Media

Amirhossein Arvin,Mohammad Hadi Fattahi,Mohammad Sedghi-Asl,Seyyed Abbas Mohammadi 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.4

For non-Darcy flow in coarse porous media, an analytical solution based on the Homotopy Perturbation Method (HPM) is proposed. Subsurface water profile data of a laboratory model are used for six different inlet discharges in both rounded and crushed coarse porous media types. The model slope is S = 0.00001 close to the horizon. Different upstream and downstreamwater level boundary conditions are considered. The results of the analytical solution of non-Darcy flow by the HPM method are compared with experimental data. The normal objective function (NOF) is used for better comparison between the results of analytical solutions and experimental data. Results depict that the HPM method provides acceptable solutions in both rounded and crushed media types. The analytical results of flow rates q = 26.25 lit/s with NOF of 0.000294586 percent in rounded porous media and q = 30 lit/s with NOF of 0.00028660 percent in crushed one are the most consistent with the experimental data. The proposed HPM solution performs very well, particularly at higher flow rates, in both rounded and crushed porous media.

Two-phase flow friction at high void fraction in porous media with small particles and its impact on dryout heat flux evaluation

Lee, M.,Park, H.S.,Park, J.H.,Moriyama, K.,Kim, M.H. Elsevier 2019 International journal of multiphase flow Vol.118 No.-

<P><B>Abstract</B></P> <P>The effect of interfacial friction at a high void fraction on the estimation of the dryout heat flux (DHF) of particle beds under co-current two-phase flow conditions is investigated. The objective is to reduce uncertainties in the assessment of debris bed coolability during a severe accident in a light water reactor (LWR).</P> <P>A review of porous media air/water pressure drop experiments and friction models in the literature revealed that the existing models cannot adequately predict the interfacial friction at high void fraction. In this study, interfacial friction at high void fraction is suggested and corresponding modifications to the flow pattern map and other friction terms are presented. The proposed model shows an acceptable agreement with the experimental data of both the air/water two-phase pressure drop and DHF experimental results within the particle size range of 2–4 mm, similar to the average diameter of debris particles (2.5–3.5 mm, Hong and An, 2018) obtained from fuel coolant interaction tests.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Improvement of two-phase friction model for high void fraction range in porous media. </LI> <LI> Modified flow pattern map for channel and annular flow in porous media. </LI> <LI> Model validation with air-water two-phase pressure drop and dryout experimental data in porous media. </LI> </UL> </P>