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    Simulation of multi-component multi-phase fluid flow in two-dimensional anisotropic heterogeneous porous media using high-order control volume distributed methods

    , Article Computers and Mathematics with Applications ; Volume 78, Issue 10 , 2019 , Pages 3303-3328 ; 08981221 (ISSN) Moshiri, M ; Taghizadeh Manzari, M ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    In this paper, flow of multi-component two-phase fluids in highly heterogeneous anisotropic two-dimensional porous media is studied using computational methods suitable for unstructured triangular and/or quadrilateral grids. The physical model accounts for miscibility and compressibility of fluids while gravity and capillary effects are neglected. The governing equations consist of a pressure equation together with a system of mass conservation equations. For solving pressure equation, a new method called Control Volume Distributed Finite Element Method (CVDFEM) is introduced which uses Control Volume Distributed (CVD) vertex-centered grids. It is shown that the proposed method is able to... 

    An experimental study of the matrix-fracture interaction during miscible displacement in fractured porous media: A micromodel study

    , Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, issue. 3 , Oct , 2010 , p. 259-266 ; ISSN: 15567036 Saidian, M ; Masihi, M ; Ghazanfari, M. H ; Kharrat, R ; Mohammadi, S ; Sharif University of Technology
    Abstract
    During miscible displacements in fractured porous media, one of the most important factors that plays a significant role in oil production is the matrix-fracture interaction. In this work, a series of hydrocarbon injection experiments have been performed on a fractured glass micromodel that was designed specifically to study matrix-fracture interaction. A high quality image analysis method was used to determine the fluid flow behavior, solvent front movement, and viscous fingering associated with solvent movement in matrix and fractures. Observations showed that in the case of unit viscosity ratio, the injection rate increased the slope of recovery curve and consequently improved the final... 

    Investigation of diffusion and deposition of TiO2 nanoparticles in sandstone rocks for EOR application

    , Article 76th European Association of Geoscientists and Engineers Conference and Exhibition 2014: Experience the Energy - Incorporating SPE EUROPEC 2014 ; 19 June , 2014 , pp. 1031-1035 Ehtesabi, H ; Ahadian, M. M ; Taghikhani, V ; Sharif University of Technology
    Abstract
    The diffusion and deposition of TiO2 nanoparticles in EOR application was investigated in this paper. TEM image of nanoparticles showed that the particles are elongated with average long and short axis sizes of 54 and 15 nm. Water flooding tests showed that the recovery factor can be improved from 49% to 80% using TiO2 nanoparticles. Viscosity and interfacial tension measurements showed that by using TiO2 nanoparticles the viscosity of injected fluid and interfacial tension do not change significantly and can not explain the change in recovery factor. Contact angle measurements showed that nanoparticles deposition changed the wettability of the rock surface from oil-wet to water-wet. SEM... 

    Properties of Nafion Under Uniaxial Loading at Different Temperatures: A Molecular Dynamics Study

    , Article Polymer - Plastics Technology and Engineering ; Volume 54, Issue 8 , 2015 , Pages 806-813 ; 03602559 (ISSN) Ozmaian, M ; Naghdabadi, R ; Sharif University of Technology
    Taylor and Francis Inc  2015
    Abstract
    Nafion membrane encounters many different thermal conditions and mechanical loadings because of its wide range of applications as a proton exchange membrane (PEM). Molecular dynamics simulation of hydrated Nafion at different temperatures is carried out to investigate the alteration of the physical properties of Nafion under uniaxial loading over a wide range of temperatures. According to the simulation results, increase of the temperature reduces the yield stress. The results also show that the polymer chains ordering increases the glass transition temperature and enhances the self-diffusion coefficient of water in hydrated Nafion. Comparisons show that the elastic modulus and viscosity... 

    3D modeling of reaction-diffusion dynamics in an electrokinetic Y-shaped microreactor

    , Article Sensors and Actuators, B: Chemical ; Volume 235 , 2016 , Pages 343-355 ; 09254005 (ISSN) Helisaz, H ; Saidi, M. H ; Sadeghi, A ; Sharif University of Technology
    Elsevier  2016
    Abstract
    We perform a 3D numerical modeling of reaction-diffusion dynamics in a Y-shaped microreactor, considering a fully developed combined electroosmotic and pressure-driven flow. The governing equations, based on a second-order irreversible reaction, are solved invoking a finite-volume approach for a non-uniform grid system. We demonstrate that the reaction is highly position dependent: more production is observed adjacent to the horizontal walls for a favorable pressure gradient, whereas both the wall and centerline are the regions of highest production when a back pressure is applied. We further show that, to achieve the maximum production rate, the EDL should be thick enough, the pressure... 

    A finite-volume ELLAM for non-linear flux convection-diffusion problems

    , Article International Journal of Non-Linear Mechanics ; Volume 44, Issue 2 , 2009 , Pages 129-136 ; 00207462 (ISSN) Fatehi, R ; Taghizadeh Manzari, M ; Kazemzadeh Hannani, S ; Sharif University of Technology
    2009
    Abstract
    In this paper, a modified finite-volume Eulerian-Lagrangian localized adjoint method (FVELLAM) extended for convection-diffusion problems with a non-linear flux function is introduced. Tracking schemes are discussed using viscous Burgers' equation. It is shown that in order to have smooth results, only the new time level values should be used in tracking process. Then, the proposed method is employed to study immiscible incompressible two-phase flows in porous media. Various one- and two-dimensional test cases involving internal sources and sinks are solved and accuracy of solution and performance of the method are investigated by comparing the results obtained using FVELLAM with those of... 

    Nanofluid flooding for enhanced oil recovery in a heterogeneous two-dimensional anticline geometry

    , Article International Communications in Heat and Mass Transfer ; Volume 118 , November , 2020 Hemmat Esfe, M ; Esfandeh, S ; Hosseinizadeh, E ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    In the present study, we try to numerically simulate the nanofluid flooding method, which is one of the newest methods in this field. For this purpose, the nanofluid is considered as a single phase fluid that enters the porous petroleum reservoir containing oil. Since all porous petroleum reservoirs are heterogeneous, the porous grid is also considered heterogeneous and is solved using the finite element numerical method. The geometry considered in this study is a two-dimensional anticline medium that is heterogeneous. In this study, the effect of using different volume fractions of nanoparticles in nanofluid is studied. Capillary pressure or diffusion are considered in simulation and their... 

    An analytical model for molecular communication over a non-linear reaction-diffusion medium

    , Article IEEE Transactions on Communications ; Volume 69, Issue 12 , 2021 , Pages 8042-8054 ; 00906778 (ISSN) Abin, H ; Gohari, A ; Nasiri Kenari, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Abstract
    One of the main challenges in diffusion-based molecular communication is dealing with the non-linearity of reaction-diffusion chemical equations. While numerical methods can be used to solve these equations, a change in the input signals or the parameters of the medium requires one to redo the simulations. This makes it difficult to design modulation schemes and practically impossible to prove the optimality of a given transmission strategy. In this paper, we provide an analytical technique for modeling the non-linearity of chemical reaction equations based on the perturbation method. The perturbation method expresses the solution in terms of an infinite power series. An approximate solution... 

    An Analytical model for molecular communication over a Non-Linear reaction-diffusion medium

    , Article IEEE Transactions on Communications ; Volume 69, Issue 12 , 2021 , Pages 8042-8054 ; 00906778 (ISSN) Abin, H ; Gohari, A ; Nasiri Kenari, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Abstract
    One of the main challenges in diffusion-based molecular communication is dealing with the non-linearity of reaction-diffusion chemical equations. While numerical methods can be used to solve these equations, a change in the input signals or the parameters of the medium requires one to redo the simulations. This makes it difficult to design modulation schemes and practically impossible to prove the optimality of a given transmission strategy. In this paper, we provide an analytical technique for modeling the non-linearity of chemical reaction equations based on the perturbation method. The perturbation method expresses the solution in terms of an infinite power series. An approximate solution... 

    Interfacial instabilities in sediment suspension flows

    , Article Journal of Fluid Mechanics ; Vol. 758, issue , November , 2014 , p. 312-326 Abedi, M ; Jalali, M. A ; Maleki, M ; Sharif University of Technology
    Abstract
    We report the existence of interfacial instability in the two-dimensional channel flow of a sediment suspension whose particles diffuse in the carrier fluid due to shear-induced collisions. We derive partial differential equations that govern the deformations of the interface between the sediment suspension and the clear fluid, and devise a perturbation method that preserves the positivity of the particle volume fraction. We solve perturbed momentum, particle transport and deforming interface equations to show that a Kelvin-Helmholtz-type unstable wave develops at the interface for wavelengths longer than a critical value. Short-wavelength oscillations of the interface are damped due to... 

    A new scheme for improving the mixing efficiency in micro scale

    , Article ASME 2011 9th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM 2011 ; Volume 1 , 2011 , Pages 183-191 ; 9780791844632 (ISBN) Anbari, A. M ; Haroutunian, A ; Saidi, M. S ; Shafii, M. B ; Sharif University of Technology
    2011
    Abstract
    Generally speaking, most micro-fluidic mixing systems are limited to the low Reynolds number regime in which diffusion dominates convection, and consequently the mixing process tends to be slow and it takes a relatively long time to have two fluids completely mixed. Therefore, rapid mixing is essential in micro-fluidic systems. In order to hasten the mixing process in micro scale, in this study we come up with a novel scheme for a two dimensional micro-fluidic mixer which encompasses three pairs of electrodes, one pair embedded in the mixing chamber and two pairs located in the micro-channels before and after the mixing chamber. The width of the middle pair is assumed to be twice of the... 

    Experimental investigation of gas-heavy oil molecular diffusion coefficient in porous media: Experimental results for CO2 in Iranian Crudes

    , Article Defect and Diffusion Forum ; Volume 312-315 , 2011 , Pages 1049-1054 ; 10120386 (ISSN) ; 9783037851173 (ISBN) Mirjordavi, N ; Kazemeini, M ; Kharrat, R ; Ghazanfari, M. H ; Salehi, A ; Sharif University of Technology
    Abstract
    Molecular diffusion of gases in crude oils plays a crucial role in several oil recovery processes especially in cold-based production process. However, experimental data concerning CO2 diffusivity in heavy oils due to the tedious nature of diffusivity measurements are relatively rare in the open literature. In this work, a comprehensive experimental investigation of the effective molecular diffusion determination of CO2-heavy oil systems in homogeneous porous media was studied. The so-called pressure decay method was applied to measure the molecular diffusivity of carbon dioxide in heavy oil. Furthermore, effect of various parameters such as initial pressure, temperature and porous media on... 

    A depthwise averaging solution for cross-stream diffusion in a Y-micromixer by considering thick electrical double layers and nonlinear rheology

    , Article Microfluidics and Nanofluidics ; Volume 19, Issue 6 , 2015 , Pages 1297-1308 ; 16134982 (ISSN) Ahmadian Yazdi, A ; Sadeghi, A ; Saidi, M. H ; Sharif University of Technology
    Springer Verlag  2015
    Abstract
    Both nonlinear rheology and finite EDL thickness effects on the mixing process in an electroosmotically actuated Y-sensor are being investigated in this paper, utilizing a depthwise averaging method based on the Taylor dispersion theory. The fluid rheological behavior is assumed to obey the power-law viscosity model. Analytical solutions are obtained assuming a large channel width to depth ratio for which a 1-D profile can efficiently describe the velocity distribution. Full numerical simulations are also performed to determine the applicability range of the analytical model, revealing that it is able to provide accurate results for channel aspect ratios of ten and higher and quite... 

    Influence of butyl side chain elimination, tail amine functional addition, and c2 methylation on the dynamics and transport properties of imidazolium-based [Tf2N-] ionic liquids from molecular dynamics simulations

    , Article Journal of Chemical and Engineering Data ; Volume 60, Issue 3 , January , 2015 , Pages 551-560 ; 00219568 (ISSN) Kowsari, M. H ; Fakhraee, M ; Sharif University of Technology
    American Chemical Society  2015
    Abstract
    Molecular dynamics simulations of four ionic liquids (ILs) based on the [Tf2N] bis(trifluoromethanesulfonyl)imide anion, and imidazolium cations with different alkyl side chains have been performed. These simulations investigate the influence of butyl side chain elimination, tail amine functional addition, and C2 methylation on the dynamics and transport properties of this family of ionic liquids at 400 K. In our earlier work (J. Chem. Eng. Data, 2014, 59, 2834-2849), a suite of thermodynamic quantities and microscopic structures of these ILs were studied by classical molecular dynamics simulations and ab initio calculations. In this work, the dynamics of the ILs are studied by calculating... 

    Mass transport analysis of non-Newtonian fluids under combined electroosmotically and pressure driven flow in rectangular microreactors

    , Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 508 , 2016 , Pages 345-359 ; 09277757 (ISSN) Yousefian, Z ; Saidi, M. H ; Sharif University of Technology
    Elsevier 
    Abstract
    Hydrodynamically fully developed flow of power-law fluids under combined action of electroosmotic and pressure gradient forces in rectangular microreactors is analyzed considering heterogeneous catalytic reactions. The Poisson-Boltzmann, Cauchy momentum, and concentration equations are considered in two dimensions and after being dimensionless are numerically solved applying a finite difference algorithm. Variation of axial concentration gradient, and axial and horizontal mass diffusions are taken into account as well. To accomplish a more general analysis, the velocity distribution is obtained by solving continuity and Cauchy momentum equations and is not considered as an average axial... 

    Study of self-diffusion in two binary solutions, glycerol-water and methanol-water using diffusion-ordered spectroscopy

    , Article Scientia Iranica ; Volume 23, Issue 3 , 2016 , Pages 1175-1183 ; 10263098 (ISSN) Fadaei, E ; Tafazzoli, M ; Sharif University of Technology
    Sharif University of Technology 
    Abstract
    The concentration and temperature behaviors of the self-diffusion coefficient were analyzed in glycerol-water and methanol-water solutions using Diffusion-Ordered Spectroscopy (DOSY) experiment. Our results indicate that the self-diffusion coefficient dips with increasing concentration and decreasing temperature. The concentration behavior shows that there is hydrogen bond interaction between water and alcohol, which declines the self-diffusion coefficients of both in the aqueous binary mixtures. The self-diffusion activation energies were estimated 13.6, 29.4, and 32.8 (kJ/mol) for methanol and 24.8, 25.5, and 27.6 (kJ/mol) for water in the methanol-water solutions with 0.03, 0.10, and 0.20... 

    Reduction of production rate in y-shaped microreactors in the presence of viscoelasticity

    , Article Analytica Chimica Acta ; Volume 990 , 2017 , Pages 121-134 ; 00032670 (ISSN) Helisaz, H ; Saidi, M. H ; Sadeghi, A ; Sharif University of Technology
    Abstract
    The viscoelasticity effects on the reaction-diffusion rates in a Y-shaped microreactor are studied utilizing the PTT rheological model. The flow is assumed to be fully developed and considered to be created under a combined action of electroosmotic and pressure forces. In general, finite-volume-based numerical simulations are conducted to handle the problem; however, analytical solutions based on the depthwise averaging approach are also obtained for the case for which there is no reaction between the inlet components. The analytical solutions are found to predict accurate results when the width to height ratio is at least 10 and acceptable results for lower aspect ratios. An investigation... 

    Numerical study of n-heptane/benzene separation by thermal diffusion column

    , Article Chinese Journal of Chemical Engineering ; Volume 27, Issue 8 , 2019 , Pages 1745-1755 ; 10049541 (ISSN) Hashemipour, N ; Karimi Sabet, J ; Motahari, K ; Mahruz Monfared, S ; Amini, Y ; Moosavian, M. A ; Sharif University of Technology
    Chemical Industry Press  2019
    Abstract
    In this article, numerical simulations are performed to investigate the performance of the thermal diffusion column for the separation of n-heptane/benzene mixture. The present work tried to optimize column by analyzing significant parameters such as feed flow rate, temperature and cut. In order to obtain the hydrodynamic and temperature and mass distribution inside thermal diffusion column, computational fluid dynamic (CFD) method is applied to solve the Navier–Stocks equations. Numerical simulations are conducted to study the main parameters in both stationary and time-dependent conditions. By using the separation work unit as a function of cut, the optimal cut for maximum SWU occurs... 

    Investigation on nanofluid flooding effect on enhancement oil recovery process in a random pore distribution incomplete cone

    , Article International Communications in Heat and Mass Transfer ; Volume 117 , October , 2020 Hemmat Esfe, M ; Hosseinizadeh, E ; Mosaferi, M ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    By reducing the exploration of new oil reservoirs, enhanced oil recovery from previous oil reservoirs is a solution to supply energy demand. In order to develop the production, various technologies and methods have been proposed such as steaming, direct heating, flooding by nano-fluid, chemical injection, polymer injection and etc. In the present study, nanofluid flooding has been attempted on a rock reservoir with incomplete cone geometry and its performance has been evaluated on oil recovery. The porous media is considered heterogeneous in simulation in accordance with oil reservoirs. The heterogeneous geometry considered in this study is incomplete cone that is heterogeneous in a random... 

    Numerical modeling of density-driven solute transport in fractured porous media with the extended finite element method

    , Article Advances in Water Resources ; Volume 136 , 2020 Hosseini, N ; Bajalan, Z ; Khoei, A. R ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    In this paper, a numerical model is developed based on the X-FEM technique to simulate the transport of dense solute in a single fluid phase through the fractured porous media. The governing equation is based on the mass conservation law which is applied to the fluid phase and the solute in both matrix and fracture domain. The integral governing equations of the mass exchange between the fracture and the surrounding matrix is derived. The extended finite element method (X-FEM) is applied by employing appropriate enrichment functions to model the fractured porous domain. The superiority of the X-FEM is that the FE mesh is not necessary to be conformed to the fracture geometry, so the regular...