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    Modified MODFLOW-based model for simulating the agglomeration and transport of polymer-modified Fe0 nanoparticles in saturated porous media

    , Article Environmental Science and Pollution Research ; 2015 ; 09441344 (ISSN) Babakhani, P ; Fagerlund, F ; Shamsai, A ; Lowry, G. V ; Phenrat, T ; Sharif University of Technology
    Springer Verlag  2015
    Abstract
    The solute transport model MODFLOW has become a standard tool in risk assessment and remediation design. However, particle transport models that take into account both particle agglomeration and deposition phenomena are far less developed. The main objective of the present study was to evaluate the feasibility of adapting the standard code MODFLOW/MT3D to simulate the agglomeration and transport of three different types of polymer-modified nanoscale zerovalent iron (NZVI) in one-dimensional (1-D) and two-dimensional (2-D) saturated porous media. A first-order decay of the particle population was used to account for the agglomeration of particles. An iterative technique was used to optimize... 

    An irregular lattice pore network model construction algorithm

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 29, Issue 1 , 2010 , Pages 61-70 ; 10219986 (ISSN) Jamshidi, S ; Bozorghmehry Boozarjomehry, R ; Pishvaie, S. M. R ; Sharif University of Technology
    2010
    Abstract
    Pore network modeling uses a network of pores connected by throats to model the void space of a porous medium and tries to predict its various characteristics during multiphase flow of various fluids. In most cases, a non-realistic regular lattice of pores is used to model the characteristics of a porous medium. Although some methodologies for extracting geologically realistic irregular networks from pore space images have been presented, these methods require some experimental data which are either unavailable or costly to obtain. 3-dimensional image or 2-dimensional SEM images are among these types of data. In this paper a new irregular lattice algorithm for the construction of these... 

    Experimental study of internal forced convection of ferrofluid flow in non-magnetizable/magnetizable porous media

    , Article Experimental Thermal and Fluid Science ; Volume 96 , 2018 , Pages 441-450 ; 08941777 (ISSN) Shafii, M. B ; Keshavarz, M ; Sharif University of Technology
    Elsevier Inc  2018
    Abstract
    In this work, the thermal and hydrodynamic performance of ferromagnetic fluid, which flows through a copper tube in thermal entrance region, has been studied. The flow in the tube is laminar and subjected to constant heat flux. A part of the tube contains a porous medium with paramagnetic properties and porosity of 0.46. Ferrofluid is composed of Fe3o4 and water with (CH3)4NOH as a surfactant that is prepared in three different volume fractions. The effects of constant and oscillating magnetic fields on convective heat transfer coefficient were examined for various Reynolds numbers, frequencies and volume fractions. The results show that the maximum enhancements of average heat transfer... 

    Modified MODFLOW-based model for simulating the agglomeration and transport of polymer-modified Fe0 nanoparticles in saturated porous media

    , Article Environmental Science and Pollution Research ; Volume 25, Issue 8 , 2018 , Pages 7180-7199 ; 09441344 (ISSN) Babakhani, P ; Fagerlund, F ; Shamsai, A ; Lowry, G. V ; Phenrat, T ; Sharif University of Technology
    Springer Verlag  2018
    Abstract
    The solute transport model MODFLOW has become a standard tool in risk assessment and remediation design. However, particle transport models that take into account both particle agglomeration and deposition phenomena are far less developed. The main objective of the present study was to evaluate the feasibility of adapting the standard code MODFLOW/MT3D to simulate the agglomeration and transport of three different types of polymer-modified nanoscale zerovalent iron (NZVI) in one-dimensional (1-D) and two-dimensional (2-D) saturated porous media. A first-order decay of the particle population was used to account for the agglomeration of particles. An iterative technique was used to optimize... 

    Unstable density-driven flow in fractured porous media: The fractured elder problem

    , Article Fluids ; Volume 4, Issue 3 , 2019 ; 23115521 (ISSN) Shafabakhsh, P ; Fahs, M ; Ataie Ashtiani, B ; Simmons, C. T ; Sharif University of Technology
    MDPI AG  2019
    Abstract
    The Elder problem is one of the well-known examples of an unstable density-driven flow (DDF) and solute transport in porous media. The goal of this research is to investigate the influence of fracture networks on this benchmark problem due to the great importance of the fractured heterogeneity effect on unstable DDF. For this aim, the fractured Elder problem is solved using COMSOL Multiphysics, which is a finite element method simulator. Uniform and orthogonal fracture networks are embedded to analyze free convective flow and development of unstable salt plumes. The results indicate that the mesh sensitivity of the fractured Elder problem is greater than the homogeneous case. Furthermore, it... 

    Metal foam and fin implementation into a triple concentric tube heat exchanger over melting evolution

    , Article Theoretical and Applied Mechanics Letters ; Volume 12, Issue 2 , 2022 ; 20950349 (ISSN) Moghaddam, M. A. E ; Hassani Soukht Abandani, M. R ; Hosseinzadeh, K ; Shafii, M. B ; Ganji, D. D ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    It is believed that it is going to be a sizeable mismatch between supply and demand when it comes to renewable resources. Lately, researchers are on course to compensate for the unpredictabilityof such resources by the employment of phase change materials (PCMs). Having multiple advantages, PCMs generally suffer from inadequate thermal conductivity which causes prolonged transition procedures. To tackle this issue, this study is fixated on two parameterswhich are linked to fins addition and porous media incorporation in a melting process within a triple concentric tube heat exchanger (TCTHX). The results provided by multiple cases underlined the significance of natural convection in the bare... 

    Modeling of Heat Transfer Mechanism in Porous Media Combustion Chamber

    , M.Sc. Thesis Sharif University of Technology Arzhangnia, Yousef (Author) ; Ghafourian Morshed Yazdi, Akbar (Supervisor) ; Saeedi, Mohammad Hassan (Supervisor)
    Abstract
    Combustion procedure in porous media is of great importance and also has numerous technical applications. Currently several usages of porous burners in thermodynamic engineering and thermal industries have been identified, in which they perform based on stabilized combustion in porous media. Among the advantages that porous burners have over conventional burners are pollution reduction, decrease in burner dimension, enhanced flame stabilization and also noise reduction.
    According to physical and chemical attributes of porous material, combustion can occur in one of the three main types of media including: inert, catalytic, combustible. The concepts mentioned in this proposal are... 

    A bridge between dual porosity and multiscale models of heterogeneous deformable porous media

    , Article International Journal for Numerical and Analytical Methods in Geomechanics ; 2018 ; 03639061 (ISSN) Hajiabadi, M. R ; Khoei, A. R ; Sharif University of Technology
    John Wiley and Sons Ltd  2018
    Abstract
    In this paper, a multiscale homogenization approach is developed for fully coupled saturated porous media to represent the idealized sugar cube model, which is generally employed in fractured porous media on the basis of dual porosity models. In this manner, an extended version of the Hill-Mandel theory that incorporates the microdynamic effects into the multiscale analysis is presented, and the concept of the deformable dual porosity model is demonstrated. Numerical simulations are performed employing the multiscale analysis and dual porosity model, and the results are compared with the direct numerical simulation through 2 numerical examples. Finally, a combined multiscale-dual porosity... 

    Investigation of Fouling In Clarification of Non-Alcoholic Beer with Crossflow Microfiltration Membranes

    , M.Sc. Thesis Sharif University of Technology Hajipour Shirazifard, Mastaneh (Author) ; Soltanieh, Mohammad (Supervisor)
    Abstract
    In the present work, numerical simulation of cross-flow microfiltration of non-alcoholic beer in a tubular membrane has been studied. Finite element analysis was used as a powerful tool for simulation. The feed stream, which flows mainly tangentially to the porous membrane surface, is modeled by the Navier-Stokes equations. Porous wall conditions are described by the Darcy equation that relates the pressure gradient within a flow stream to the flow rate through the permeable wall. A pilot-scale cross-flow membrane filter was developed to verify the model results. Ceramic tubular membranes were used in this study. The cross-flow velocity of the feed solution was controlled at the laminar... 

    Study on the Influence of Nanoparticle and Magnetic Field on Flow in Porous Media

    , M.Sc. Thesis Sharif University of Technology Jafari, Amin (Author) ; Molaei Dehkordi, Asghar (Supervisor)
    Abstract
    In this thesis, the momentum and heat transfer of a ferrofluid in a partially filled vertical porous channel under the influence of nonuniform magnetic field has been investigated. In this magneto-thermo-echanical problem, our objective was to enhance the heat transfer which is attributable to both ferrofluid and porous medium unique characteristics. Accordingly, this problem is twofold and their relevant aspects would be discussed respectively. The ferrofluid flows upward, in the channel and a gradient magnetic field is generated by a permanent magnet in the vicinity of the channel. To solve the system of govering equations,COMSOL Multiphysics software has been used. The results shows that... 

    Numerical Study of Effective Factors in Polyurethane Injection in Porous Media

    , M.Sc. Thesis Sharif University of Technology Bazkhane, Saed (Author) ; Sadr Hosseini, Hani (Supervisor) ; Afshin, Hossein (Supervisor)
    Abstract
    Porous medium is a material consisting of a solid matrix with an interconnected void. A polymer is a large molecule composed of many repeated subunits, known as monomers; Polyurethane is a type of polymer which has many uses. The aim of this research project is to investigate the effective factors in polyurethane polymer injection and the behavior of this material during the foaming in cavities with different soil porosities (0.15 < φ < 0.4). Parameters such as thermal boundary conditions and the soil material that could be effective in solidification of polyurethane are analyzed, numerically using FLUENT software. A simplified model for foaming is presented in this study which can be used... 

    Investigation on Wettability Alteration of Reservoir Rock During Adsorption of Organic Component of Crude Oil

    , M.Sc. Thesis Sharif University of Technology Monjezi, Reza (Author) ; Ghotbi, Siroos (Supervisor) ; Jafari Behbahani, Taraneh (Supervisor) ; Baghalha, Morteza (Supervisor)
    Abstract
    This study investigates the dynamic adsorption of asphaltene-in-toluene solutions on pack of wet calcite. All experiments were performed on mineral packs in sand-pack with mesh sizes between 100 to 140 (105 to 150 micron) and porosities between 40 to 46 percent. A UV–vis spectrophotometer was used to monitor the outlet concentration of asphaltenes. Experiments were performed for seven ionic strength of sodium chloride (6 to 1500 mM), five ionic strength of sodium sulfate (6 to 2400 mM) and four ionic strength of these salts mixture (12 to 3300 mM). In previous experiments the asphaltene concentration is 500 mg/l. Also two experments were performed with asphaltene concentration of 2000... 

    Simulation of Fluid Flow in Porous Media with Pipe Flow Model

    , M.Sc. Thesis Sharif University of Technology Mostafanezhad Asl Marand, Shahaboddin (Author) ; Rouhani, Shahin (Supervisor)
    Abstract
    Understanding of how fluid flow through porous media has many application in industry like Water filters technology and Gravel dams. also it’s very important in oil industry in areas like oil tank engineering. For doing this important thing many peoples tried to find out how fluid flows through the porous media they already invented the various kind of models, .the model used in this thesise is called pipe flow model which people use this model before but what I did have a little difference I used random lattice which people did not paid attention to it so the result of this model will be more trustable and close to what happens in nature. The result of this simulation showed us that the... 

    Experimental Study & Mathematical Modeling of Asphaltene Deposition in Porous Media

    , Ph.D. Dissertation Sharif University of Technology Bagheri, Mohammad Bagher (Author) ; Kharrat, Riyaz (Supervisor) ; Ghotbi, Siroos (Supervisor)
    Abstract
    Asphaltene precipitation and deposition may cause severe problems during different stages of oil recovery. All proposed remediation techniques have proven costly and not highly effective, so prevention becomes the most beneficial way to counteract the problem. Revelation of the deposition mechanism and determination of the parameters are necessary in order to devise reliable prevention strategies.This work presents results of the effect of lean gas and CO2 injection process as well as natural depletion on dynamic asphaltene precipitation and deposition. In addition sets of experiments were performed in the same porous media using STO and solvent (with different volume ratios) to investigate... 

    Convective stability of carbon sequestration in anisotropic porous media

    , Article Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences ; Vol. 470, Issue. 2170 , 2014 ; ISSN: 13645021 Hill, A. A ; Morad, M. R ; Sharif University of Technology
    Abstract
    The stability of convection in an anisotropic porous medium, where the solute concentration is assumed to decay via a first-order chemical reaction, is studied. This is a simplified model for the interactions between carbon dioxide and brine in underground aquifers; the instability of which is essential in reducing reservoir mixing times. The key purpose of this paper is to explore the role porous media anisotropy plays in convective instabilities. It is shown that varying the ratio of horizontal to vertical solutal diffusivites does not significantly affect the behaviour of the instability. This is also the case for changes of permeability when the diffusion rate dominates the solute... 

    A multi-resolution multiscale finite volume method for simulation of fluid flows in heterogeneous porous media

    , Article Journal of Computational Physics ; Volume 248 , September , 2013 , Pages 339-362 ; 00219991 (ISSN) Mosharaf Dehkordi, M ; Taghizadeh Manzari, M ; Sharif University of Technology
    2013
    Abstract
    This paper presents an extension of the multiscale finite volume (MsFV) method to multi-resolution coarse grid solvers for single phase incompressible flows. To achieve this, a grid one level coarser than the coarse grids used in the MsFV method is constructed and the local problems are redefined to compute the basis and correction functions associated with this new grid. To construct the coarse-scale pressure equations, the coarse-scale transmissibility coefficients are calculated using a new multi-point flux approximation (MPFA) method. The estimated coarse-scale pressures are utilized to compute the multiscale pressure solution. Finally a reconstruction step is performed to produce a... 

    New lifting relations for estimating LBM distribution functions from corresponding macroscopic quantities, based on equilibrium and non-equilibrium moments

    , Article Journal of Computational Physics ; Volume 302 , 2015 , Pages 155-175 ; 00219991 (ISSN) Salimi, M. R ; Taeibi Rahni, M ; Sharif University of Technology
    Abstract
    Due to superior accuracy and stability of multiple relaxation time (MRT) collision operator over its single relaxation time (SRT) counterpart, new lifting relations are proposed here to construct single particle distribution functions for MRT-LBM from macroscopic variables. Using these lifting relations, a new hybrid FVM-LB method is presented (called Finite type-LB hybrid method), which is consistent with MRT-LBM. In this new hybrid method, single-particle distribution functions in MRT-LBM sub-domain boundaries are computed, using equilibrium and non-equilibrium moments. These moments are computed in Navier-Stokes/FVM sub-domain boundaries, using macroscopic variables and their derivatives.... 

    Numerical modeling of two-phase fluid flow in deformable fractured porous media using the extended finite element method and an equivalent continuum model

    , Article Advances in Water Resources ; Volume 94 , August , 2016 , Pages 510–528 ; 03091708 (ISSN) Khoei, A. R ; Hosseini, N ; Mohammadnejad, T ; Sharif University of Technology
    Elsevier Ltd  2016
    Abstract
    In the present paper, a numerical model is developed based on a combination of the extended finite element method and an equivalent continuum model to simulate the two-phase fluid flow through fractured porous media containing fractures with multiple length scales. The governing equations involve the linear momentum balance equation and the flow continuity equation for each fluid phase. The extended finite element method allows for an explicit and accurate representation of cracks by enriching the standard finite element approximation of the field variables with appropriate enrichment functions, and captures the mass transfer between the fracture and the matrix. Due to the high computational... 

    XFEM, strong discontinuities and second-order work in shear band modeling of saturated porous media

    , Article Acta Geotechnica ; Volume 13, Issue 6 , 2018 , Pages 1249-1264 ; 18611125 (ISSN) Mikaeili, E ; Schrefler, B ; Sharif University of Technology
    Abstract
    We investigate shear band initiation and propagation in fully saturated porous media by means of a combination of strong discontinuities (discontinuities in the displacement field) and XFEM. As a constitutive behavior of the solid phase, a Drucker–Prager model is used within a framework of non-associated plasticity to account for dilation of the sample. Strong discontinuities circumvent the difficulties which appear when trying to model shear band formation in the context of classical nonlinear continuum mechanics and when trying to resolve them with classical numerical methods like the finite element method. XFEM, on the other hand, is well suited to deal with problems where a discontinuity... 

    Numerical modelling of two-phase flow in a geocentrifuge

    , Article Environmental Modelling and Software ; Volume 18, Issue 3 , 2003 , Pages 231-241 ; 13648152 (ISSN) Ataie Ashtiani, B ; Hassanizadeh, S. M ; Oung, O ; Weststrate, F. A ; Bezuijen, A ; Sharif University of Technology
    Elsevier BV  2003
    Abstract
    In this paper, results of DNAPL spreading experiments carried out in a geocentrifuge are analysed. The experiments are performed in the GeoDelft geocentrifuge. The experiments investigate the intrusion of a known amount of PCE into a water-saturated soil sample. They are carried out under 12, 15, and 30g conditions. The objectives of these experiments were to assess the potential of geocentrifuge tests for the study of environmental problems, to investigate the effect of acceleration on the spreading of DNAPL, and to determine whether capillary pressure-saturation (Pc-S) curves of soils measured in a geocentrifuge are applicable under 1g conditions. In the present paper, numerical simulation...